xref: /openbmc/linux/drivers/gpu/drm/drm_connector.c (revision 465191d6)
1 /*
2  * Copyright (c) 2016 Intel Corporation
3  *
4  * Permission to use, copy, modify, distribute, and sell this software and its
5  * documentation for any purpose is hereby granted without fee, provided that
6  * the above copyright notice appear in all copies and that both that copyright
7  * notice and this permission notice appear in supporting documentation, and
8  * that the name of the copyright holders not be used in advertising or
9  * publicity pertaining to distribution of the software without specific,
10  * written prior permission.  The copyright holders make no representations
11  * about the suitability of this software for any purpose.  It is provided "as
12  * is" without express or implied warranty.
13  *
14  * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
15  * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
16  * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
17  * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
18  * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
19  * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
20  * OF THIS SOFTWARE.
21  */
22 
23 #include <drm/drm_auth.h>
24 #include <drm/drm_connector.h>
25 #include <drm/drm_edid.h>
26 #include <drm/drm_encoder.h>
27 #include <drm/drm_utils.h>
28 #include <drm/drm_print.h>
29 #include <drm/drm_drv.h>
30 #include <drm/drm_file.h>
31 #include <drm/drm_privacy_screen_consumer.h>
32 #include <drm/drm_sysfs.h>
33 
34 #include <linux/uaccess.h>
35 
36 #include "drm_crtc_internal.h"
37 #include "drm_internal.h"
38 
39 /**
40  * DOC: overview
41  *
42  * In DRM connectors are the general abstraction for display sinks, and include
43  * also fixed panels or anything else that can display pixels in some form. As
44  * opposed to all other KMS objects representing hardware (like CRTC, encoder or
45  * plane abstractions) connectors can be hotplugged and unplugged at runtime.
46  * Hence they are reference-counted using drm_connector_get() and
47  * drm_connector_put().
48  *
49  * KMS driver must create, initialize, register and attach at a &struct
50  * drm_connector for each such sink. The instance is created as other KMS
51  * objects and initialized by setting the following fields. The connector is
52  * initialized with a call to drm_connector_init() with a pointer to the
53  * &struct drm_connector_funcs and a connector type, and then exposed to
54  * userspace with a call to drm_connector_register().
55  *
56  * Connectors must be attached to an encoder to be used. For devices that map
57  * connectors to encoders 1:1, the connector should be attached at
58  * initialization time with a call to drm_connector_attach_encoder(). The
59  * driver must also set the &drm_connector.encoder field to point to the
60  * attached encoder.
61  *
62  * For connectors which are not fixed (like built-in panels) the driver needs to
63  * support hotplug notifications. The simplest way to do that is by using the
64  * probe helpers, see drm_kms_helper_poll_init() for connectors which don't have
65  * hardware support for hotplug interrupts. Connectors with hardware hotplug
66  * support can instead use e.g. drm_helper_hpd_irq_event().
67  */
68 
69 /*
70  * Global connector list for drm_connector_find_by_fwnode().
71  * Note drm_connector_[un]register() first take connector->lock and then
72  * take the connector_list_lock.
73  */
74 static DEFINE_MUTEX(connector_list_lock);
75 static LIST_HEAD(connector_list);
76 
77 struct drm_conn_prop_enum_list {
78 	int type;
79 	const char *name;
80 	struct ida ida;
81 };
82 
83 /*
84  * Connector and encoder types.
85  */
86 static struct drm_conn_prop_enum_list drm_connector_enum_list[] = {
87 	{ DRM_MODE_CONNECTOR_Unknown, "Unknown" },
88 	{ DRM_MODE_CONNECTOR_VGA, "VGA" },
89 	{ DRM_MODE_CONNECTOR_DVII, "DVI-I" },
90 	{ DRM_MODE_CONNECTOR_DVID, "DVI-D" },
91 	{ DRM_MODE_CONNECTOR_DVIA, "DVI-A" },
92 	{ DRM_MODE_CONNECTOR_Composite, "Composite" },
93 	{ DRM_MODE_CONNECTOR_SVIDEO, "SVIDEO" },
94 	{ DRM_MODE_CONNECTOR_LVDS, "LVDS" },
95 	{ DRM_MODE_CONNECTOR_Component, "Component" },
96 	{ DRM_MODE_CONNECTOR_9PinDIN, "DIN" },
97 	{ DRM_MODE_CONNECTOR_DisplayPort, "DP" },
98 	{ DRM_MODE_CONNECTOR_HDMIA, "HDMI-A" },
99 	{ DRM_MODE_CONNECTOR_HDMIB, "HDMI-B" },
100 	{ DRM_MODE_CONNECTOR_TV, "TV" },
101 	{ DRM_MODE_CONNECTOR_eDP, "eDP" },
102 	{ DRM_MODE_CONNECTOR_VIRTUAL, "Virtual" },
103 	{ DRM_MODE_CONNECTOR_DSI, "DSI" },
104 	{ DRM_MODE_CONNECTOR_DPI, "DPI" },
105 	{ DRM_MODE_CONNECTOR_WRITEBACK, "Writeback" },
106 	{ DRM_MODE_CONNECTOR_SPI, "SPI" },
107 	{ DRM_MODE_CONNECTOR_USB, "USB" },
108 };
109 
110 void drm_connector_ida_init(void)
111 {
112 	int i;
113 
114 	for (i = 0; i < ARRAY_SIZE(drm_connector_enum_list); i++)
115 		ida_init(&drm_connector_enum_list[i].ida);
116 }
117 
118 void drm_connector_ida_destroy(void)
119 {
120 	int i;
121 
122 	for (i = 0; i < ARRAY_SIZE(drm_connector_enum_list); i++)
123 		ida_destroy(&drm_connector_enum_list[i].ida);
124 }
125 
126 /**
127  * drm_get_connector_type_name - return a string for connector type
128  * @type: The connector type (DRM_MODE_CONNECTOR_*)
129  *
130  * Returns: the name of the connector type, or NULL if the type is not valid.
131  */
132 const char *drm_get_connector_type_name(unsigned int type)
133 {
134 	if (type < ARRAY_SIZE(drm_connector_enum_list))
135 		return drm_connector_enum_list[type].name;
136 
137 	return NULL;
138 }
139 EXPORT_SYMBOL(drm_get_connector_type_name);
140 
141 /**
142  * drm_connector_get_cmdline_mode - reads the user's cmdline mode
143  * @connector: connector to query
144  *
145  * The kernel supports per-connector configuration of its consoles through
146  * use of the video= parameter. This function parses that option and
147  * extracts the user's specified mode (or enable/disable status) for a
148  * particular connector. This is typically only used during the early fbdev
149  * setup.
150  */
151 static void drm_connector_get_cmdline_mode(struct drm_connector *connector)
152 {
153 	struct drm_cmdline_mode *mode = &connector->cmdline_mode;
154 	char *option = NULL;
155 
156 	if (fb_get_options(connector->name, &option))
157 		return;
158 
159 	if (!drm_mode_parse_command_line_for_connector(option,
160 						       connector,
161 						       mode))
162 		return;
163 
164 	if (mode->force) {
165 		DRM_INFO("forcing %s connector %s\n", connector->name,
166 			 drm_get_connector_force_name(mode->force));
167 		connector->force = mode->force;
168 	}
169 
170 	if (mode->panel_orientation != DRM_MODE_PANEL_ORIENTATION_UNKNOWN) {
171 		DRM_INFO("cmdline forces connector %s panel_orientation to %d\n",
172 			 connector->name, mode->panel_orientation);
173 		drm_connector_set_panel_orientation(connector,
174 						    mode->panel_orientation);
175 	}
176 
177 	DRM_DEBUG_KMS("cmdline mode for connector %s %s %dx%d@%dHz%s%s%s\n",
178 		      connector->name, mode->name,
179 		      mode->xres, mode->yres,
180 		      mode->refresh_specified ? mode->refresh : 60,
181 		      mode->rb ? " reduced blanking" : "",
182 		      mode->margins ? " with margins" : "",
183 		      mode->interlace ?  " interlaced" : "");
184 }
185 
186 static void drm_connector_free(struct kref *kref)
187 {
188 	struct drm_connector *connector =
189 		container_of(kref, struct drm_connector, base.refcount);
190 	struct drm_device *dev = connector->dev;
191 
192 	drm_mode_object_unregister(dev, &connector->base);
193 	connector->funcs->destroy(connector);
194 }
195 
196 void drm_connector_free_work_fn(struct work_struct *work)
197 {
198 	struct drm_connector *connector, *n;
199 	struct drm_device *dev =
200 		container_of(work, struct drm_device, mode_config.connector_free_work);
201 	struct drm_mode_config *config = &dev->mode_config;
202 	unsigned long flags;
203 	struct llist_node *freed;
204 
205 	spin_lock_irqsave(&config->connector_list_lock, flags);
206 	freed = llist_del_all(&config->connector_free_list);
207 	spin_unlock_irqrestore(&config->connector_list_lock, flags);
208 
209 	llist_for_each_entry_safe(connector, n, freed, free_node) {
210 		drm_mode_object_unregister(dev, &connector->base);
211 		connector->funcs->destroy(connector);
212 	}
213 }
214 
215 /**
216  * drm_connector_init - Init a preallocated connector
217  * @dev: DRM device
218  * @connector: the connector to init
219  * @funcs: callbacks for this connector
220  * @connector_type: user visible type of the connector
221  *
222  * Initialises a preallocated connector. Connectors should be
223  * subclassed as part of driver connector objects.
224  *
225  * Returns:
226  * Zero on success, error code on failure.
227  */
228 int drm_connector_init(struct drm_device *dev,
229 		       struct drm_connector *connector,
230 		       const struct drm_connector_funcs *funcs,
231 		       int connector_type)
232 {
233 	struct drm_mode_config *config = &dev->mode_config;
234 	int ret;
235 	struct ida *connector_ida =
236 		&drm_connector_enum_list[connector_type].ida;
237 
238 	WARN_ON(drm_drv_uses_atomic_modeset(dev) &&
239 		(!funcs->atomic_destroy_state ||
240 		 !funcs->atomic_duplicate_state));
241 
242 	ret = __drm_mode_object_add(dev, &connector->base,
243 				    DRM_MODE_OBJECT_CONNECTOR,
244 				    false, drm_connector_free);
245 	if (ret)
246 		return ret;
247 
248 	connector->base.properties = &connector->properties;
249 	connector->dev = dev;
250 	connector->funcs = funcs;
251 
252 	/* connector index is used with 32bit bitmasks */
253 	ret = ida_simple_get(&config->connector_ida, 0, 32, GFP_KERNEL);
254 	if (ret < 0) {
255 		DRM_DEBUG_KMS("Failed to allocate %s connector index: %d\n",
256 			      drm_connector_enum_list[connector_type].name,
257 			      ret);
258 		goto out_put;
259 	}
260 	connector->index = ret;
261 	ret = 0;
262 
263 	connector->connector_type = connector_type;
264 	connector->connector_type_id =
265 		ida_simple_get(connector_ida, 1, 0, GFP_KERNEL);
266 	if (connector->connector_type_id < 0) {
267 		ret = connector->connector_type_id;
268 		goto out_put_id;
269 	}
270 	connector->name =
271 		kasprintf(GFP_KERNEL, "%s-%d",
272 			  drm_connector_enum_list[connector_type].name,
273 			  connector->connector_type_id);
274 	if (!connector->name) {
275 		ret = -ENOMEM;
276 		goto out_put_type_id;
277 	}
278 
279 	INIT_LIST_HEAD(&connector->global_connector_list_entry);
280 	INIT_LIST_HEAD(&connector->probed_modes);
281 	INIT_LIST_HEAD(&connector->modes);
282 	mutex_init(&connector->mutex);
283 	connector->edid_blob_ptr = NULL;
284 	connector->epoch_counter = 0;
285 	connector->tile_blob_ptr = NULL;
286 	connector->status = connector_status_unknown;
287 	connector->display_info.panel_orientation =
288 		DRM_MODE_PANEL_ORIENTATION_UNKNOWN;
289 
290 	drm_connector_get_cmdline_mode(connector);
291 
292 	/* We should add connectors at the end to avoid upsetting the connector
293 	 * index too much.
294 	 */
295 	spin_lock_irq(&config->connector_list_lock);
296 	list_add_tail(&connector->head, &config->connector_list);
297 	config->num_connector++;
298 	spin_unlock_irq(&config->connector_list_lock);
299 
300 	if (connector_type != DRM_MODE_CONNECTOR_VIRTUAL &&
301 	    connector_type != DRM_MODE_CONNECTOR_WRITEBACK)
302 		drm_connector_attach_edid_property(connector);
303 
304 	drm_object_attach_property(&connector->base,
305 				      config->dpms_property, 0);
306 
307 	drm_object_attach_property(&connector->base,
308 				   config->link_status_property,
309 				   0);
310 
311 	drm_object_attach_property(&connector->base,
312 				   config->non_desktop_property,
313 				   0);
314 	drm_object_attach_property(&connector->base,
315 				   config->tile_property,
316 				   0);
317 
318 	if (drm_core_check_feature(dev, DRIVER_ATOMIC)) {
319 		drm_object_attach_property(&connector->base, config->prop_crtc_id, 0);
320 	}
321 
322 	connector->debugfs_entry = NULL;
323 out_put_type_id:
324 	if (ret)
325 		ida_simple_remove(connector_ida, connector->connector_type_id);
326 out_put_id:
327 	if (ret)
328 		ida_simple_remove(&config->connector_ida, connector->index);
329 out_put:
330 	if (ret)
331 		drm_mode_object_unregister(dev, &connector->base);
332 
333 	return ret;
334 }
335 EXPORT_SYMBOL(drm_connector_init);
336 
337 /**
338  * drm_connector_init_with_ddc - Init a preallocated connector
339  * @dev: DRM device
340  * @connector: the connector to init
341  * @funcs: callbacks for this connector
342  * @connector_type: user visible type of the connector
343  * @ddc: pointer to the associated ddc adapter
344  *
345  * Initialises a preallocated connector. Connectors should be
346  * subclassed as part of driver connector objects.
347  *
348  * Ensures that the ddc field of the connector is correctly set.
349  *
350  * Returns:
351  * Zero on success, error code on failure.
352  */
353 int drm_connector_init_with_ddc(struct drm_device *dev,
354 				struct drm_connector *connector,
355 				const struct drm_connector_funcs *funcs,
356 				int connector_type,
357 				struct i2c_adapter *ddc)
358 {
359 	int ret;
360 
361 	ret = drm_connector_init(dev, connector, funcs, connector_type);
362 	if (ret)
363 		return ret;
364 
365 	/* provide ddc symlink in sysfs */
366 	connector->ddc = ddc;
367 
368 	return ret;
369 }
370 EXPORT_SYMBOL(drm_connector_init_with_ddc);
371 
372 /**
373  * drm_connector_attach_edid_property - attach edid property.
374  * @connector: the connector
375  *
376  * Some connector types like DRM_MODE_CONNECTOR_VIRTUAL do not get a
377  * edid property attached by default.  This function can be used to
378  * explicitly enable the edid property in these cases.
379  */
380 void drm_connector_attach_edid_property(struct drm_connector *connector)
381 {
382 	struct drm_mode_config *config = &connector->dev->mode_config;
383 
384 	drm_object_attach_property(&connector->base,
385 				   config->edid_property,
386 				   0);
387 }
388 EXPORT_SYMBOL(drm_connector_attach_edid_property);
389 
390 /**
391  * drm_connector_attach_encoder - attach a connector to an encoder
392  * @connector: connector to attach
393  * @encoder: encoder to attach @connector to
394  *
395  * This function links up a connector to an encoder. Note that the routing
396  * restrictions between encoders and crtcs are exposed to userspace through the
397  * possible_clones and possible_crtcs bitmasks.
398  *
399  * Returns:
400  * Zero on success, negative errno on failure.
401  */
402 int drm_connector_attach_encoder(struct drm_connector *connector,
403 				 struct drm_encoder *encoder)
404 {
405 	/*
406 	 * In the past, drivers have attempted to model the static association
407 	 * of connector to encoder in simple connector/encoder devices using a
408 	 * direct assignment of connector->encoder = encoder. This connection
409 	 * is a logical one and the responsibility of the core, so drivers are
410 	 * expected not to mess with this.
411 	 *
412 	 * Note that the error return should've been enough here, but a large
413 	 * majority of drivers ignores the return value, so add in a big WARN
414 	 * to get people's attention.
415 	 */
416 	if (WARN_ON(connector->encoder))
417 		return -EINVAL;
418 
419 	connector->possible_encoders |= drm_encoder_mask(encoder);
420 
421 	return 0;
422 }
423 EXPORT_SYMBOL(drm_connector_attach_encoder);
424 
425 /**
426  * drm_connector_has_possible_encoder - check if the connector and encoder are
427  * associated with each other
428  * @connector: the connector
429  * @encoder: the encoder
430  *
431  * Returns:
432  * True if @encoder is one of the possible encoders for @connector.
433  */
434 bool drm_connector_has_possible_encoder(struct drm_connector *connector,
435 					struct drm_encoder *encoder)
436 {
437 	return connector->possible_encoders & drm_encoder_mask(encoder);
438 }
439 EXPORT_SYMBOL(drm_connector_has_possible_encoder);
440 
441 static void drm_mode_remove(struct drm_connector *connector,
442 			    struct drm_display_mode *mode)
443 {
444 	list_del(&mode->head);
445 	drm_mode_destroy(connector->dev, mode);
446 }
447 
448 /**
449  * drm_connector_cleanup - cleans up an initialised connector
450  * @connector: connector to cleanup
451  *
452  * Cleans up the connector but doesn't free the object.
453  */
454 void drm_connector_cleanup(struct drm_connector *connector)
455 {
456 	struct drm_device *dev = connector->dev;
457 	struct drm_display_mode *mode, *t;
458 
459 	/* The connector should have been removed from userspace long before
460 	 * it is finally destroyed.
461 	 */
462 	if (WARN_ON(connector->registration_state ==
463 		    DRM_CONNECTOR_REGISTERED))
464 		drm_connector_unregister(connector);
465 
466 	if (connector->privacy_screen) {
467 		drm_privacy_screen_put(connector->privacy_screen);
468 		connector->privacy_screen = NULL;
469 	}
470 
471 	if (connector->tile_group) {
472 		drm_mode_put_tile_group(dev, connector->tile_group);
473 		connector->tile_group = NULL;
474 	}
475 
476 	list_for_each_entry_safe(mode, t, &connector->probed_modes, head)
477 		drm_mode_remove(connector, mode);
478 
479 	list_for_each_entry_safe(mode, t, &connector->modes, head)
480 		drm_mode_remove(connector, mode);
481 
482 	ida_simple_remove(&drm_connector_enum_list[connector->connector_type].ida,
483 			  connector->connector_type_id);
484 
485 	ida_simple_remove(&dev->mode_config.connector_ida,
486 			  connector->index);
487 
488 	kfree(connector->display_info.bus_formats);
489 	drm_mode_object_unregister(dev, &connector->base);
490 	kfree(connector->name);
491 	connector->name = NULL;
492 	fwnode_handle_put(connector->fwnode);
493 	connector->fwnode = NULL;
494 	spin_lock_irq(&dev->mode_config.connector_list_lock);
495 	list_del(&connector->head);
496 	dev->mode_config.num_connector--;
497 	spin_unlock_irq(&dev->mode_config.connector_list_lock);
498 
499 	WARN_ON(connector->state && !connector->funcs->atomic_destroy_state);
500 	if (connector->state && connector->funcs->atomic_destroy_state)
501 		connector->funcs->atomic_destroy_state(connector,
502 						       connector->state);
503 
504 	mutex_destroy(&connector->mutex);
505 
506 	memset(connector, 0, sizeof(*connector));
507 }
508 EXPORT_SYMBOL(drm_connector_cleanup);
509 
510 /**
511  * drm_connector_register - register a connector
512  * @connector: the connector to register
513  *
514  * Register userspace interfaces for a connector. Only call this for connectors
515  * which can be hotplugged after drm_dev_register() has been called already,
516  * e.g. DP MST connectors. All other connectors will be registered automatically
517  * when calling drm_dev_register().
518  *
519  * Returns:
520  * Zero on success, error code on failure.
521  */
522 int drm_connector_register(struct drm_connector *connector)
523 {
524 	int ret = 0;
525 
526 	if (!connector->dev->registered)
527 		return 0;
528 
529 	mutex_lock(&connector->mutex);
530 	if (connector->registration_state != DRM_CONNECTOR_INITIALIZING)
531 		goto unlock;
532 
533 	ret = drm_sysfs_connector_add(connector);
534 	if (ret)
535 		goto unlock;
536 
537 	drm_debugfs_connector_add(connector);
538 
539 	if (connector->funcs->late_register) {
540 		ret = connector->funcs->late_register(connector);
541 		if (ret)
542 			goto err_debugfs;
543 	}
544 
545 	drm_mode_object_register(connector->dev, &connector->base);
546 
547 	connector->registration_state = DRM_CONNECTOR_REGISTERED;
548 
549 	/* Let userspace know we have a new connector */
550 	drm_sysfs_connector_hotplug_event(connector);
551 
552 	if (connector->privacy_screen)
553 		drm_privacy_screen_register_notifier(connector->privacy_screen,
554 					   &connector->privacy_screen_notifier);
555 
556 	mutex_lock(&connector_list_lock);
557 	list_add_tail(&connector->global_connector_list_entry, &connector_list);
558 	mutex_unlock(&connector_list_lock);
559 	goto unlock;
560 
561 err_debugfs:
562 	drm_debugfs_connector_remove(connector);
563 	drm_sysfs_connector_remove(connector);
564 unlock:
565 	mutex_unlock(&connector->mutex);
566 	return ret;
567 }
568 EXPORT_SYMBOL(drm_connector_register);
569 
570 /**
571  * drm_connector_unregister - unregister a connector
572  * @connector: the connector to unregister
573  *
574  * Unregister userspace interfaces for a connector. Only call this for
575  * connectors which have registered explicitly by calling drm_dev_register(),
576  * since connectors are unregistered automatically when drm_dev_unregister() is
577  * called.
578  */
579 void drm_connector_unregister(struct drm_connector *connector)
580 {
581 	mutex_lock(&connector->mutex);
582 	if (connector->registration_state != DRM_CONNECTOR_REGISTERED) {
583 		mutex_unlock(&connector->mutex);
584 		return;
585 	}
586 
587 	mutex_lock(&connector_list_lock);
588 	list_del_init(&connector->global_connector_list_entry);
589 	mutex_unlock(&connector_list_lock);
590 
591 	if (connector->privacy_screen)
592 		drm_privacy_screen_unregister_notifier(
593 					connector->privacy_screen,
594 					&connector->privacy_screen_notifier);
595 
596 	if (connector->funcs->early_unregister)
597 		connector->funcs->early_unregister(connector);
598 
599 	drm_sysfs_connector_remove(connector);
600 	drm_debugfs_connector_remove(connector);
601 
602 	connector->registration_state = DRM_CONNECTOR_UNREGISTERED;
603 	mutex_unlock(&connector->mutex);
604 }
605 EXPORT_SYMBOL(drm_connector_unregister);
606 
607 void drm_connector_unregister_all(struct drm_device *dev)
608 {
609 	struct drm_connector *connector;
610 	struct drm_connector_list_iter conn_iter;
611 
612 	drm_connector_list_iter_begin(dev, &conn_iter);
613 	drm_for_each_connector_iter(connector, &conn_iter)
614 		drm_connector_unregister(connector);
615 	drm_connector_list_iter_end(&conn_iter);
616 }
617 
618 int drm_connector_register_all(struct drm_device *dev)
619 {
620 	struct drm_connector *connector;
621 	struct drm_connector_list_iter conn_iter;
622 	int ret = 0;
623 
624 	drm_connector_list_iter_begin(dev, &conn_iter);
625 	drm_for_each_connector_iter(connector, &conn_iter) {
626 		ret = drm_connector_register(connector);
627 		if (ret)
628 			break;
629 	}
630 	drm_connector_list_iter_end(&conn_iter);
631 
632 	if (ret)
633 		drm_connector_unregister_all(dev);
634 	return ret;
635 }
636 
637 /**
638  * drm_get_connector_status_name - return a string for connector status
639  * @status: connector status to compute name of
640  *
641  * In contrast to the other drm_get_*_name functions this one here returns a
642  * const pointer and hence is threadsafe.
643  *
644  * Returns: connector status string
645  */
646 const char *drm_get_connector_status_name(enum drm_connector_status status)
647 {
648 	if (status == connector_status_connected)
649 		return "connected";
650 	else if (status == connector_status_disconnected)
651 		return "disconnected";
652 	else
653 		return "unknown";
654 }
655 EXPORT_SYMBOL(drm_get_connector_status_name);
656 
657 /**
658  * drm_get_connector_force_name - return a string for connector force
659  * @force: connector force to get name of
660  *
661  * Returns: const pointer to name.
662  */
663 const char *drm_get_connector_force_name(enum drm_connector_force force)
664 {
665 	switch (force) {
666 	case DRM_FORCE_UNSPECIFIED:
667 		return "unspecified";
668 	case DRM_FORCE_OFF:
669 		return "off";
670 	case DRM_FORCE_ON:
671 		return "on";
672 	case DRM_FORCE_ON_DIGITAL:
673 		return "digital";
674 	default:
675 		return "unknown";
676 	}
677 }
678 
679 #ifdef CONFIG_LOCKDEP
680 static struct lockdep_map connector_list_iter_dep_map = {
681 	.name = "drm_connector_list_iter"
682 };
683 #endif
684 
685 /**
686  * drm_connector_list_iter_begin - initialize a connector_list iterator
687  * @dev: DRM device
688  * @iter: connector_list iterator
689  *
690  * Sets @iter up to walk the &drm_mode_config.connector_list of @dev. @iter
691  * must always be cleaned up again by calling drm_connector_list_iter_end().
692  * Iteration itself happens using drm_connector_list_iter_next() or
693  * drm_for_each_connector_iter().
694  */
695 void drm_connector_list_iter_begin(struct drm_device *dev,
696 				   struct drm_connector_list_iter *iter)
697 {
698 	iter->dev = dev;
699 	iter->conn = NULL;
700 	lock_acquire_shared_recursive(&connector_list_iter_dep_map, 0, 1, NULL, _RET_IP_);
701 }
702 EXPORT_SYMBOL(drm_connector_list_iter_begin);
703 
704 /*
705  * Extra-safe connector put function that works in any context. Should only be
706  * used from the connector_iter functions, where we never really expect to
707  * actually release the connector when dropping our final reference.
708  */
709 static void
710 __drm_connector_put_safe(struct drm_connector *conn)
711 {
712 	struct drm_mode_config *config = &conn->dev->mode_config;
713 
714 	lockdep_assert_held(&config->connector_list_lock);
715 
716 	if (!refcount_dec_and_test(&conn->base.refcount.refcount))
717 		return;
718 
719 	llist_add(&conn->free_node, &config->connector_free_list);
720 	schedule_work(&config->connector_free_work);
721 }
722 
723 /**
724  * drm_connector_list_iter_next - return next connector
725  * @iter: connector_list iterator
726  *
727  * Returns: the next connector for @iter, or NULL when the list walk has
728  * completed.
729  */
730 struct drm_connector *
731 drm_connector_list_iter_next(struct drm_connector_list_iter *iter)
732 {
733 	struct drm_connector *old_conn = iter->conn;
734 	struct drm_mode_config *config = &iter->dev->mode_config;
735 	struct list_head *lhead;
736 	unsigned long flags;
737 
738 	spin_lock_irqsave(&config->connector_list_lock, flags);
739 	lhead = old_conn ? &old_conn->head : &config->connector_list;
740 
741 	do {
742 		if (lhead->next == &config->connector_list) {
743 			iter->conn = NULL;
744 			break;
745 		}
746 
747 		lhead = lhead->next;
748 		iter->conn = list_entry(lhead, struct drm_connector, head);
749 
750 		/* loop until it's not a zombie connector */
751 	} while (!kref_get_unless_zero(&iter->conn->base.refcount));
752 
753 	if (old_conn)
754 		__drm_connector_put_safe(old_conn);
755 	spin_unlock_irqrestore(&config->connector_list_lock, flags);
756 
757 	return iter->conn;
758 }
759 EXPORT_SYMBOL(drm_connector_list_iter_next);
760 
761 /**
762  * drm_connector_list_iter_end - tear down a connector_list iterator
763  * @iter: connector_list iterator
764  *
765  * Tears down @iter and releases any resources (like &drm_connector references)
766  * acquired while walking the list. This must always be called, both when the
767  * iteration completes fully or when it was aborted without walking the entire
768  * list.
769  */
770 void drm_connector_list_iter_end(struct drm_connector_list_iter *iter)
771 {
772 	struct drm_mode_config *config = &iter->dev->mode_config;
773 	unsigned long flags;
774 
775 	iter->dev = NULL;
776 	if (iter->conn) {
777 		spin_lock_irqsave(&config->connector_list_lock, flags);
778 		__drm_connector_put_safe(iter->conn);
779 		spin_unlock_irqrestore(&config->connector_list_lock, flags);
780 	}
781 	lock_release(&connector_list_iter_dep_map, _RET_IP_);
782 }
783 EXPORT_SYMBOL(drm_connector_list_iter_end);
784 
785 static const struct drm_prop_enum_list drm_subpixel_enum_list[] = {
786 	{ SubPixelUnknown, "Unknown" },
787 	{ SubPixelHorizontalRGB, "Horizontal RGB" },
788 	{ SubPixelHorizontalBGR, "Horizontal BGR" },
789 	{ SubPixelVerticalRGB, "Vertical RGB" },
790 	{ SubPixelVerticalBGR, "Vertical BGR" },
791 	{ SubPixelNone, "None" },
792 };
793 
794 /**
795  * drm_get_subpixel_order_name - return a string for a given subpixel enum
796  * @order: enum of subpixel_order
797  *
798  * Note you could abuse this and return something out of bounds, but that
799  * would be a caller error.  No unscrubbed user data should make it here.
800  *
801  * Returns: string describing an enumerated subpixel property
802  */
803 const char *drm_get_subpixel_order_name(enum subpixel_order order)
804 {
805 	return drm_subpixel_enum_list[order].name;
806 }
807 EXPORT_SYMBOL(drm_get_subpixel_order_name);
808 
809 static const struct drm_prop_enum_list drm_dpms_enum_list[] = {
810 	{ DRM_MODE_DPMS_ON, "On" },
811 	{ DRM_MODE_DPMS_STANDBY, "Standby" },
812 	{ DRM_MODE_DPMS_SUSPEND, "Suspend" },
813 	{ DRM_MODE_DPMS_OFF, "Off" }
814 };
815 DRM_ENUM_NAME_FN(drm_get_dpms_name, drm_dpms_enum_list)
816 
817 static const struct drm_prop_enum_list drm_link_status_enum_list[] = {
818 	{ DRM_MODE_LINK_STATUS_GOOD, "Good" },
819 	{ DRM_MODE_LINK_STATUS_BAD, "Bad" },
820 };
821 
822 /**
823  * drm_display_info_set_bus_formats - set the supported bus formats
824  * @info: display info to store bus formats in
825  * @formats: array containing the supported bus formats
826  * @num_formats: the number of entries in the fmts array
827  *
828  * Store the supported bus formats in display info structure.
829  * See MEDIA_BUS_FMT_* definitions in include/uapi/linux/media-bus-format.h for
830  * a full list of available formats.
831  *
832  * Returns:
833  * 0 on success or a negative error code on failure.
834  */
835 int drm_display_info_set_bus_formats(struct drm_display_info *info,
836 				     const u32 *formats,
837 				     unsigned int num_formats)
838 {
839 	u32 *fmts = NULL;
840 
841 	if (!formats && num_formats)
842 		return -EINVAL;
843 
844 	if (formats && num_formats) {
845 		fmts = kmemdup(formats, sizeof(*formats) * num_formats,
846 			       GFP_KERNEL);
847 		if (!fmts)
848 			return -ENOMEM;
849 	}
850 
851 	kfree(info->bus_formats);
852 	info->bus_formats = fmts;
853 	info->num_bus_formats = num_formats;
854 
855 	return 0;
856 }
857 EXPORT_SYMBOL(drm_display_info_set_bus_formats);
858 
859 /* Optional connector properties. */
860 static const struct drm_prop_enum_list drm_scaling_mode_enum_list[] = {
861 	{ DRM_MODE_SCALE_NONE, "None" },
862 	{ DRM_MODE_SCALE_FULLSCREEN, "Full" },
863 	{ DRM_MODE_SCALE_CENTER, "Center" },
864 	{ DRM_MODE_SCALE_ASPECT, "Full aspect" },
865 };
866 
867 static const struct drm_prop_enum_list drm_aspect_ratio_enum_list[] = {
868 	{ DRM_MODE_PICTURE_ASPECT_NONE, "Automatic" },
869 	{ DRM_MODE_PICTURE_ASPECT_4_3, "4:3" },
870 	{ DRM_MODE_PICTURE_ASPECT_16_9, "16:9" },
871 };
872 
873 static const struct drm_prop_enum_list drm_content_type_enum_list[] = {
874 	{ DRM_MODE_CONTENT_TYPE_NO_DATA, "No Data" },
875 	{ DRM_MODE_CONTENT_TYPE_GRAPHICS, "Graphics" },
876 	{ DRM_MODE_CONTENT_TYPE_PHOTO, "Photo" },
877 	{ DRM_MODE_CONTENT_TYPE_CINEMA, "Cinema" },
878 	{ DRM_MODE_CONTENT_TYPE_GAME, "Game" },
879 };
880 
881 static const struct drm_prop_enum_list drm_panel_orientation_enum_list[] = {
882 	{ DRM_MODE_PANEL_ORIENTATION_NORMAL,	"Normal"	},
883 	{ DRM_MODE_PANEL_ORIENTATION_BOTTOM_UP,	"Upside Down"	},
884 	{ DRM_MODE_PANEL_ORIENTATION_LEFT_UP,	"Left Side Up"	},
885 	{ DRM_MODE_PANEL_ORIENTATION_RIGHT_UP,	"Right Side Up"	},
886 };
887 
888 static const struct drm_prop_enum_list drm_dvi_i_select_enum_list[] = {
889 	{ DRM_MODE_SUBCONNECTOR_Automatic, "Automatic" }, /* DVI-I and TV-out */
890 	{ DRM_MODE_SUBCONNECTOR_DVID,      "DVI-D"     }, /* DVI-I  */
891 	{ DRM_MODE_SUBCONNECTOR_DVIA,      "DVI-A"     }, /* DVI-I  */
892 };
893 DRM_ENUM_NAME_FN(drm_get_dvi_i_select_name, drm_dvi_i_select_enum_list)
894 
895 static const struct drm_prop_enum_list drm_dvi_i_subconnector_enum_list[] = {
896 	{ DRM_MODE_SUBCONNECTOR_Unknown,   "Unknown"   }, /* DVI-I, TV-out and DP */
897 	{ DRM_MODE_SUBCONNECTOR_DVID,      "DVI-D"     }, /* DVI-I  */
898 	{ DRM_MODE_SUBCONNECTOR_DVIA,      "DVI-A"     }, /* DVI-I  */
899 };
900 DRM_ENUM_NAME_FN(drm_get_dvi_i_subconnector_name,
901 		 drm_dvi_i_subconnector_enum_list)
902 
903 static const struct drm_prop_enum_list drm_tv_select_enum_list[] = {
904 	{ DRM_MODE_SUBCONNECTOR_Automatic, "Automatic" }, /* DVI-I and TV-out */
905 	{ DRM_MODE_SUBCONNECTOR_Composite, "Composite" }, /* TV-out */
906 	{ DRM_MODE_SUBCONNECTOR_SVIDEO,    "SVIDEO"    }, /* TV-out */
907 	{ DRM_MODE_SUBCONNECTOR_Component, "Component" }, /* TV-out */
908 	{ DRM_MODE_SUBCONNECTOR_SCART,     "SCART"     }, /* TV-out */
909 };
910 DRM_ENUM_NAME_FN(drm_get_tv_select_name, drm_tv_select_enum_list)
911 
912 static const struct drm_prop_enum_list drm_tv_subconnector_enum_list[] = {
913 	{ DRM_MODE_SUBCONNECTOR_Unknown,   "Unknown"   }, /* DVI-I, TV-out and DP */
914 	{ DRM_MODE_SUBCONNECTOR_Composite, "Composite" }, /* TV-out */
915 	{ DRM_MODE_SUBCONNECTOR_SVIDEO,    "SVIDEO"    }, /* TV-out */
916 	{ DRM_MODE_SUBCONNECTOR_Component, "Component" }, /* TV-out */
917 	{ DRM_MODE_SUBCONNECTOR_SCART,     "SCART"     }, /* TV-out */
918 };
919 DRM_ENUM_NAME_FN(drm_get_tv_subconnector_name,
920 		 drm_tv_subconnector_enum_list)
921 
922 static const struct drm_prop_enum_list drm_dp_subconnector_enum_list[] = {
923 	{ DRM_MODE_SUBCONNECTOR_Unknown,     "Unknown"   }, /* DVI-I, TV-out and DP */
924 	{ DRM_MODE_SUBCONNECTOR_VGA,	     "VGA"       }, /* DP */
925 	{ DRM_MODE_SUBCONNECTOR_DVID,	     "DVI-D"     }, /* DP */
926 	{ DRM_MODE_SUBCONNECTOR_HDMIA,	     "HDMI"      }, /* DP */
927 	{ DRM_MODE_SUBCONNECTOR_DisplayPort, "DP"        }, /* DP */
928 	{ DRM_MODE_SUBCONNECTOR_Wireless,    "Wireless"  }, /* DP */
929 	{ DRM_MODE_SUBCONNECTOR_Native,	     "Native"    }, /* DP */
930 };
931 
932 DRM_ENUM_NAME_FN(drm_get_dp_subconnector_name,
933 		 drm_dp_subconnector_enum_list)
934 
935 static const struct drm_prop_enum_list hdmi_colorspaces[] = {
936 	/* For Default case, driver will set the colorspace */
937 	{ DRM_MODE_COLORIMETRY_DEFAULT, "Default" },
938 	/* Standard Definition Colorimetry based on CEA 861 */
939 	{ DRM_MODE_COLORIMETRY_SMPTE_170M_YCC, "SMPTE_170M_YCC" },
940 	{ DRM_MODE_COLORIMETRY_BT709_YCC, "BT709_YCC" },
941 	/* Standard Definition Colorimetry based on IEC 61966-2-4 */
942 	{ DRM_MODE_COLORIMETRY_XVYCC_601, "XVYCC_601" },
943 	/* High Definition Colorimetry based on IEC 61966-2-4 */
944 	{ DRM_MODE_COLORIMETRY_XVYCC_709, "XVYCC_709" },
945 	/* Colorimetry based on IEC 61966-2-1/Amendment 1 */
946 	{ DRM_MODE_COLORIMETRY_SYCC_601, "SYCC_601" },
947 	/* Colorimetry based on IEC 61966-2-5 [33] */
948 	{ DRM_MODE_COLORIMETRY_OPYCC_601, "opYCC_601" },
949 	/* Colorimetry based on IEC 61966-2-5 */
950 	{ DRM_MODE_COLORIMETRY_OPRGB, "opRGB" },
951 	/* Colorimetry based on ITU-R BT.2020 */
952 	{ DRM_MODE_COLORIMETRY_BT2020_CYCC, "BT2020_CYCC" },
953 	/* Colorimetry based on ITU-R BT.2020 */
954 	{ DRM_MODE_COLORIMETRY_BT2020_RGB, "BT2020_RGB" },
955 	/* Colorimetry based on ITU-R BT.2020 */
956 	{ DRM_MODE_COLORIMETRY_BT2020_YCC, "BT2020_YCC" },
957 	/* Added as part of Additional Colorimetry Extension in 861.G */
958 	{ DRM_MODE_COLORIMETRY_DCI_P3_RGB_D65, "DCI-P3_RGB_D65" },
959 	{ DRM_MODE_COLORIMETRY_DCI_P3_RGB_THEATER, "DCI-P3_RGB_Theater" },
960 };
961 
962 /*
963  * As per DP 1.4a spec, 2.2.5.7.5 VSC SDP Payload for Pixel Encoding/Colorimetry
964  * Format Table 2-120
965  */
966 static const struct drm_prop_enum_list dp_colorspaces[] = {
967 	/* For Default case, driver will set the colorspace */
968 	{ DRM_MODE_COLORIMETRY_DEFAULT, "Default" },
969 	{ DRM_MODE_COLORIMETRY_RGB_WIDE_FIXED, "RGB_Wide_Gamut_Fixed_Point" },
970 	/* Colorimetry based on scRGB (IEC 61966-2-2) */
971 	{ DRM_MODE_COLORIMETRY_RGB_WIDE_FLOAT, "RGB_Wide_Gamut_Floating_Point" },
972 	/* Colorimetry based on IEC 61966-2-5 */
973 	{ DRM_MODE_COLORIMETRY_OPRGB, "opRGB" },
974 	/* Colorimetry based on SMPTE RP 431-2 */
975 	{ DRM_MODE_COLORIMETRY_DCI_P3_RGB_D65, "DCI-P3_RGB_D65" },
976 	/* Colorimetry based on ITU-R BT.2020 */
977 	{ DRM_MODE_COLORIMETRY_BT2020_RGB, "BT2020_RGB" },
978 	{ DRM_MODE_COLORIMETRY_BT601_YCC, "BT601_YCC" },
979 	{ DRM_MODE_COLORIMETRY_BT709_YCC, "BT709_YCC" },
980 	/* Standard Definition Colorimetry based on IEC 61966-2-4 */
981 	{ DRM_MODE_COLORIMETRY_XVYCC_601, "XVYCC_601" },
982 	/* High Definition Colorimetry based on IEC 61966-2-4 */
983 	{ DRM_MODE_COLORIMETRY_XVYCC_709, "XVYCC_709" },
984 	/* Colorimetry based on IEC 61966-2-1/Amendment 1 */
985 	{ DRM_MODE_COLORIMETRY_SYCC_601, "SYCC_601" },
986 	/* Colorimetry based on IEC 61966-2-5 [33] */
987 	{ DRM_MODE_COLORIMETRY_OPYCC_601, "opYCC_601" },
988 	/* Colorimetry based on ITU-R BT.2020 */
989 	{ DRM_MODE_COLORIMETRY_BT2020_CYCC, "BT2020_CYCC" },
990 	/* Colorimetry based on ITU-R BT.2020 */
991 	{ DRM_MODE_COLORIMETRY_BT2020_YCC, "BT2020_YCC" },
992 };
993 
994 /**
995  * DOC: standard connector properties
996  *
997  * DRM connectors have a few standardized properties:
998  *
999  * EDID:
1000  * 	Blob property which contains the current EDID read from the sink. This
1001  * 	is useful to parse sink identification information like vendor, model
1002  * 	and serial. Drivers should update this property by calling
1003  * 	drm_connector_update_edid_property(), usually after having parsed
1004  * 	the EDID using drm_add_edid_modes(). Userspace cannot change this
1005  * 	property.
1006  *
1007  * 	User-space should not parse the EDID to obtain information exposed via
1008  * 	other KMS properties (because the kernel might apply limits, quirks or
1009  * 	fixups to the EDID). For instance, user-space should not try to parse
1010  * 	mode lists from the EDID.
1011  * DPMS:
1012  * 	Legacy property for setting the power state of the connector. For atomic
1013  * 	drivers this is only provided for backwards compatibility with existing
1014  * 	drivers, it remaps to controlling the "ACTIVE" property on the CRTC the
1015  * 	connector is linked to. Drivers should never set this property directly,
1016  * 	it is handled by the DRM core by calling the &drm_connector_funcs.dpms
1017  * 	callback. For atomic drivers the remapping to the "ACTIVE" property is
1018  * 	implemented in the DRM core.
1019  *
1020  * 	Note that this property cannot be set through the MODE_ATOMIC ioctl,
1021  * 	userspace must use "ACTIVE" on the CRTC instead.
1022  *
1023  * 	WARNING:
1024  *
1025  * 	For userspace also running on legacy drivers the "DPMS" semantics are a
1026  * 	lot more complicated. First, userspace cannot rely on the "DPMS" value
1027  * 	returned by the GETCONNECTOR actually reflecting reality, because many
1028  * 	drivers fail to update it. For atomic drivers this is taken care of in
1029  * 	drm_atomic_helper_update_legacy_modeset_state().
1030  *
1031  * 	The second issue is that the DPMS state is only well-defined when the
1032  * 	connector is connected to a CRTC. In atomic the DRM core enforces that
1033  * 	"ACTIVE" is off in such a case, no such checks exists for "DPMS".
1034  *
1035  * 	Finally, when enabling an output using the legacy SETCONFIG ioctl then
1036  * 	"DPMS" is forced to ON. But see above, that might not be reflected in
1037  * 	the software value on legacy drivers.
1038  *
1039  * 	Summarizing: Only set "DPMS" when the connector is known to be enabled,
1040  * 	assume that a successful SETCONFIG call also sets "DPMS" to on, and
1041  * 	never read back the value of "DPMS" because it can be incorrect.
1042  * PATH:
1043  * 	Connector path property to identify how this sink is physically
1044  * 	connected. Used by DP MST. This should be set by calling
1045  * 	drm_connector_set_path_property(), in the case of DP MST with the
1046  * 	path property the MST manager created. Userspace cannot change this
1047  * 	property.
1048  * TILE:
1049  * 	Connector tile group property to indicate how a set of DRM connector
1050  * 	compose together into one logical screen. This is used by both high-res
1051  * 	external screens (often only using a single cable, but exposing multiple
1052  * 	DP MST sinks), or high-res integrated panels (like dual-link DSI) which
1053  * 	are not gen-locked. Note that for tiled panels which are genlocked, like
1054  * 	dual-link LVDS or dual-link DSI, the driver should try to not expose the
1055  * 	tiling and virtualise both &drm_crtc and &drm_plane if needed. Drivers
1056  * 	should update this value using drm_connector_set_tile_property().
1057  * 	Userspace cannot change this property.
1058  * link-status:
1059  *      Connector link-status property to indicate the status of link. The
1060  *      default value of link-status is "GOOD". If something fails during or
1061  *      after modeset, the kernel driver may set this to "BAD" and issue a
1062  *      hotplug uevent. Drivers should update this value using
1063  *      drm_connector_set_link_status_property().
1064  *
1065  *      When user-space receives the hotplug uevent and detects a "BAD"
1066  *      link-status, the sink doesn't receive pixels anymore (e.g. the screen
1067  *      becomes completely black). The list of available modes may have
1068  *      changed. User-space is expected to pick a new mode if the current one
1069  *      has disappeared and perform a new modeset with link-status set to
1070  *      "GOOD" to re-enable the connector.
1071  *
1072  *      If multiple connectors share the same CRTC and one of them gets a "BAD"
1073  *      link-status, the other are unaffected (ie. the sinks still continue to
1074  *      receive pixels).
1075  *
1076  *      When user-space performs an atomic commit on a connector with a "BAD"
1077  *      link-status without resetting the property to "GOOD", the sink may
1078  *      still not receive pixels. When user-space performs an atomic commit
1079  *      which resets the link-status property to "GOOD" without the
1080  *      ALLOW_MODESET flag set, it might fail because a modeset is required.
1081  *
1082  *      User-space can only change link-status to "GOOD", changing it to "BAD"
1083  *      is a no-op.
1084  *
1085  *      For backwards compatibility with non-atomic userspace the kernel
1086  *      tries to automatically set the link-status back to "GOOD" in the
1087  *      SETCRTC IOCTL. This might fail if the mode is no longer valid, similar
1088  *      to how it might fail if a different screen has been connected in the
1089  *      interim.
1090  * non_desktop:
1091  * 	Indicates the output should be ignored for purposes of displaying a
1092  * 	standard desktop environment or console. This is most likely because
1093  * 	the output device is not rectilinear.
1094  * Content Protection:
1095  *	This property is used by userspace to request the kernel protect future
1096  *	content communicated over the link. When requested, kernel will apply
1097  *	the appropriate means of protection (most often HDCP), and use the
1098  *	property to tell userspace the protection is active.
1099  *
1100  *	Drivers can set this up by calling
1101  *	drm_connector_attach_content_protection_property() on initialization.
1102  *
1103  *	The value of this property can be one of the following:
1104  *
1105  *	DRM_MODE_CONTENT_PROTECTION_UNDESIRED = 0
1106  *		The link is not protected, content is transmitted in the clear.
1107  *	DRM_MODE_CONTENT_PROTECTION_DESIRED = 1
1108  *		Userspace has requested content protection, but the link is not
1109  *		currently protected. When in this state, kernel should enable
1110  *		Content Protection as soon as possible.
1111  *	DRM_MODE_CONTENT_PROTECTION_ENABLED = 2
1112  *		Userspace has requested content protection, and the link is
1113  *		protected. Only the driver can set the property to this value.
1114  *		If userspace attempts to set to ENABLED, kernel will return
1115  *		-EINVAL.
1116  *
1117  *	A few guidelines:
1118  *
1119  *	- DESIRED state should be preserved until userspace de-asserts it by
1120  *	  setting the property to UNDESIRED. This means ENABLED should only
1121  *	  transition to UNDESIRED when the user explicitly requests it.
1122  *	- If the state is DESIRED, kernel should attempt to re-authenticate the
1123  *	  link whenever possible. This includes across disable/enable, dpms,
1124  *	  hotplug, downstream device changes, link status failures, etc..
1125  *	- Kernel sends uevent with the connector id and property id through
1126  *	  @drm_hdcp_update_content_protection, upon below kernel triggered
1127  *	  scenarios:
1128  *
1129  *		- DESIRED -> ENABLED (authentication success)
1130  *		- ENABLED -> DESIRED (termination of authentication)
1131  *	- Please note no uevents for userspace triggered property state changes,
1132  *	  which can't fail such as
1133  *
1134  *		- DESIRED/ENABLED -> UNDESIRED
1135  *		- UNDESIRED -> DESIRED
1136  *	- Userspace is responsible for polling the property or listen to uevents
1137  *	  to determine when the value transitions from ENABLED to DESIRED.
1138  *	  This signifies the link is no longer protected and userspace should
1139  *	  take appropriate action (whatever that might be).
1140  *
1141  * HDCP Content Type:
1142  *	This Enum property is used by the userspace to declare the content type
1143  *	of the display stream, to kernel. Here display stream stands for any
1144  *	display content that userspace intended to display through HDCP
1145  *	encryption.
1146  *
1147  *	Content Type of a stream is decided by the owner of the stream, as
1148  *	"HDCP Type0" or "HDCP Type1".
1149  *
1150  *	The value of the property can be one of the below:
1151  *	  - "HDCP Type0": DRM_MODE_HDCP_CONTENT_TYPE0 = 0
1152  *	  - "HDCP Type1": DRM_MODE_HDCP_CONTENT_TYPE1 = 1
1153  *
1154  *	When kernel starts the HDCP authentication (see "Content Protection"
1155  *	for details), it uses the content type in "HDCP Content Type"
1156  *	for performing the HDCP authentication with the display sink.
1157  *
1158  *	Please note in HDCP spec versions, a link can be authenticated with
1159  *	HDCP 2.2 for Content Type 0/Content Type 1. Where as a link can be
1160  *	authenticated with HDCP1.4 only for Content Type 0(though it is implicit
1161  *	in nature. As there is no reference for Content Type in HDCP1.4).
1162  *
1163  *	HDCP2.2 authentication protocol itself takes the "Content Type" as a
1164  *	parameter, which is a input for the DP HDCP2.2 encryption algo.
1165  *
1166  *	In case of Type 0 content protection request, kernel driver can choose
1167  *	either of HDCP spec versions 1.4 and 2.2. When HDCP2.2 is used for
1168  *	"HDCP Type 0", a HDCP 2.2 capable repeater in the downstream can send
1169  *	that content to a HDCP 1.4 authenticated HDCP sink (Type0 link).
1170  *	But if the content is classified as "HDCP Type 1", above mentioned
1171  *	HDCP 2.2 repeater wont send the content to the HDCP sink as it can't
1172  *	authenticate the HDCP1.4 capable sink for "HDCP Type 1".
1173  *
1174  *	Please note userspace can be ignorant of the HDCP versions used by the
1175  *	kernel driver to achieve the "HDCP Content Type".
1176  *
1177  *	At current scenario, classifying a content as Type 1 ensures that the
1178  *	content will be displayed only through the HDCP2.2 encrypted link.
1179  *
1180  *	Note that the HDCP Content Type property is introduced at HDCP 2.2, and
1181  *	defaults to type 0. It is only exposed by drivers supporting HDCP 2.2
1182  *	(hence supporting Type 0 and Type 1). Based on how next versions of
1183  *	HDCP specs are defined content Type could be used for higher versions
1184  *	too.
1185  *
1186  *	If content type is changed when "Content Protection" is not UNDESIRED,
1187  *	then kernel will disable the HDCP and re-enable with new type in the
1188  *	same atomic commit. And when "Content Protection" is ENABLED, it means
1189  *	that link is HDCP authenticated and encrypted, for the transmission of
1190  *	the Type of stream mentioned at "HDCP Content Type".
1191  *
1192  * HDR_OUTPUT_METADATA:
1193  *	Connector property to enable userspace to send HDR Metadata to
1194  *	driver. This metadata is based on the composition and blending
1195  *	policies decided by user, taking into account the hardware and
1196  *	sink capabilities. The driver gets this metadata and creates a
1197  *	Dynamic Range and Mastering Infoframe (DRM) in case of HDMI,
1198  *	SDP packet (Non-audio INFOFRAME SDP v1.3) for DP. This is then
1199  *	sent to sink. This notifies the sink of the upcoming frame's Color
1200  *	Encoding and Luminance parameters.
1201  *
1202  *	Userspace first need to detect the HDR capabilities of sink by
1203  *	reading and parsing the EDID. Details of HDR metadata for HDMI
1204  *	are added in CTA 861.G spec. For DP , its defined in VESA DP
1205  *	Standard v1.4. It needs to then get the metadata information
1206  *	of the video/game/app content which are encoded in HDR (basically
1207  *	using HDR transfer functions). With this information it needs to
1208  *	decide on a blending policy and compose the relevant
1209  *	layers/overlays into a common format. Once this blending is done,
1210  *	userspace will be aware of the metadata of the composed frame to
1211  *	be send to sink. It then uses this property to communicate this
1212  *	metadata to driver which then make a Infoframe packet and sends
1213  *	to sink based on the type of encoder connected.
1214  *
1215  *	Userspace will be responsible to do Tone mapping operation in case:
1216  *		- Some layers are HDR and others are SDR
1217  *		- HDR layers luminance is not same as sink
1218  *
1219  *	It will even need to do colorspace conversion and get all layers
1220  *	to one common colorspace for blending. It can use either GL, Media
1221  *	or display engine to get this done based on the capabilities of the
1222  *	associated hardware.
1223  *
1224  *	Driver expects metadata to be put in &struct hdr_output_metadata
1225  *	structure from userspace. This is received as blob and stored in
1226  *	&drm_connector_state.hdr_output_metadata. It parses EDID and saves the
1227  *	sink metadata in &struct hdr_sink_metadata, as
1228  *	&drm_connector.hdr_sink_metadata.  Driver uses
1229  *	drm_hdmi_infoframe_set_hdr_metadata() helper to set the HDR metadata,
1230  *	hdmi_drm_infoframe_pack() to pack the infoframe as per spec, in case of
1231  *	HDMI encoder.
1232  *
1233  * max bpc:
1234  *	This range property is used by userspace to limit the bit depth. When
1235  *	used the driver would limit the bpc in accordance with the valid range
1236  *	supported by the hardware and sink. Drivers to use the function
1237  *	drm_connector_attach_max_bpc_property() to create and attach the
1238  *	property to the connector during initialization.
1239  *
1240  * Connectors also have one standardized atomic property:
1241  *
1242  * CRTC_ID:
1243  * 	Mode object ID of the &drm_crtc this connector should be connected to.
1244  *
1245  * Connectors for LCD panels may also have one standardized property:
1246  *
1247  * panel orientation:
1248  *	On some devices the LCD panel is mounted in the casing in such a way
1249  *	that the up/top side of the panel does not match with the top side of
1250  *	the device. Userspace can use this property to check for this.
1251  *	Note that input coordinates from touchscreens (input devices with
1252  *	INPUT_PROP_DIRECT) will still map 1:1 to the actual LCD panel
1253  *	coordinates, so if userspace rotates the picture to adjust for
1254  *	the orientation it must also apply the same transformation to the
1255  *	touchscreen input coordinates. This property is initialized by calling
1256  *	drm_connector_set_panel_orientation() or
1257  *	drm_connector_set_panel_orientation_with_quirk()
1258  *
1259  * scaling mode:
1260  *	This property defines how a non-native mode is upscaled to the native
1261  *	mode of an LCD panel:
1262  *
1263  *	None:
1264  *		No upscaling happens, scaling is left to the panel. Not all
1265  *		drivers expose this mode.
1266  *	Full:
1267  *		The output is upscaled to the full resolution of the panel,
1268  *		ignoring the aspect ratio.
1269  *	Center:
1270  *		No upscaling happens, the output is centered within the native
1271  *		resolution the panel.
1272  *	Full aspect:
1273  *		The output is upscaled to maximize either the width or height
1274  *		while retaining the aspect ratio.
1275  *
1276  *	This property should be set up by calling
1277  *	drm_connector_attach_scaling_mode_property(). Note that drivers
1278  *	can also expose this property to external outputs, in which case they
1279  *	must support "None", which should be the default (since external screens
1280  *	have a built-in scaler).
1281  *
1282  * subconnector:
1283  *	This property is used by DVI-I, TVout and DisplayPort to indicate different
1284  *	connector subtypes. Enum values more or less match with those from main
1285  *	connector types.
1286  *	For DVI-I and TVout there is also a matching property "select subconnector"
1287  *	allowing to switch between signal types.
1288  *	DP subconnector corresponds to a downstream port.
1289  *
1290  * privacy-screen sw-state, privacy-screen hw-state:
1291  *	These 2 optional properties can be used to query the state of the
1292  *	electronic privacy screen that is available on some displays; and in
1293  *	some cases also control the state. If a driver implements these
1294  *	properties then both properties must be present.
1295  *
1296  *	"privacy-screen hw-state" is read-only and reflects the actual state
1297  *	of the privacy-screen, possible values: "Enabled", "Disabled,
1298  *	"Enabled-locked", "Disabled-locked". The locked states indicate
1299  *	that the state cannot be changed through the DRM API. E.g. there
1300  *	might be devices where the firmware-setup options, or a hardware
1301  *	slider-switch, offer always on / off modes.
1302  *
1303  *	"privacy-screen sw-state" can be set to change the privacy-screen state
1304  *	when not locked. In this case the driver must update the hw-state
1305  *	property to reflect the new state on completion of the commit of the
1306  *	sw-state property. Setting the sw-state property when the hw-state is
1307  *	locked must be interpreted by the driver as a request to change the
1308  *	state to the set state when the hw-state becomes unlocked. E.g. if
1309  *	"privacy-screen hw-state" is "Enabled-locked" and the sw-state
1310  *	gets set to "Disabled" followed by the user unlocking the state by
1311  *	changing the slider-switch position, then the driver must set the
1312  *	state to "Disabled" upon receiving the unlock event.
1313  *
1314  *	In some cases the privacy-screen's actual state might change outside of
1315  *	control of the DRM code. E.g. there might be a firmware handled hotkey
1316  *	which toggles the actual state, or the actual state might be changed
1317  *	through another userspace API such as writing /proc/acpi/ibm/lcdshadow.
1318  *	In this case the driver must update both the hw-state and the sw-state
1319  *	to reflect the new value, overwriting any pending state requests in the
1320  *	sw-state. Any pending sw-state requests are thus discarded.
1321  *
1322  *	Note that the ability for the state to change outside of control of
1323  *	the DRM master process means that userspace must not cache the value
1324  *	of the sw-state. Caching the sw-state value and including it in later
1325  *	atomic commits may lead to overriding a state change done through e.g.
1326  *	a firmware handled hotkey. Therefor userspace must not include the
1327  *	privacy-screen sw-state in an atomic commit unless it wants to change
1328  *	its value.
1329  */
1330 
1331 int drm_connector_create_standard_properties(struct drm_device *dev)
1332 {
1333 	struct drm_property *prop;
1334 
1335 	prop = drm_property_create(dev, DRM_MODE_PROP_BLOB |
1336 				   DRM_MODE_PROP_IMMUTABLE,
1337 				   "EDID", 0);
1338 	if (!prop)
1339 		return -ENOMEM;
1340 	dev->mode_config.edid_property = prop;
1341 
1342 	prop = drm_property_create_enum(dev, 0,
1343 				   "DPMS", drm_dpms_enum_list,
1344 				   ARRAY_SIZE(drm_dpms_enum_list));
1345 	if (!prop)
1346 		return -ENOMEM;
1347 	dev->mode_config.dpms_property = prop;
1348 
1349 	prop = drm_property_create(dev,
1350 				   DRM_MODE_PROP_BLOB |
1351 				   DRM_MODE_PROP_IMMUTABLE,
1352 				   "PATH", 0);
1353 	if (!prop)
1354 		return -ENOMEM;
1355 	dev->mode_config.path_property = prop;
1356 
1357 	prop = drm_property_create(dev,
1358 				   DRM_MODE_PROP_BLOB |
1359 				   DRM_MODE_PROP_IMMUTABLE,
1360 				   "TILE", 0);
1361 	if (!prop)
1362 		return -ENOMEM;
1363 	dev->mode_config.tile_property = prop;
1364 
1365 	prop = drm_property_create_enum(dev, 0, "link-status",
1366 					drm_link_status_enum_list,
1367 					ARRAY_SIZE(drm_link_status_enum_list));
1368 	if (!prop)
1369 		return -ENOMEM;
1370 	dev->mode_config.link_status_property = prop;
1371 
1372 	prop = drm_property_create_bool(dev, DRM_MODE_PROP_IMMUTABLE, "non-desktop");
1373 	if (!prop)
1374 		return -ENOMEM;
1375 	dev->mode_config.non_desktop_property = prop;
1376 
1377 	prop = drm_property_create(dev, DRM_MODE_PROP_BLOB,
1378 				   "HDR_OUTPUT_METADATA", 0);
1379 	if (!prop)
1380 		return -ENOMEM;
1381 	dev->mode_config.hdr_output_metadata_property = prop;
1382 
1383 	return 0;
1384 }
1385 
1386 /**
1387  * drm_mode_create_dvi_i_properties - create DVI-I specific connector properties
1388  * @dev: DRM device
1389  *
1390  * Called by a driver the first time a DVI-I connector is made.
1391  *
1392  * Returns: %0
1393  */
1394 int drm_mode_create_dvi_i_properties(struct drm_device *dev)
1395 {
1396 	struct drm_property *dvi_i_selector;
1397 	struct drm_property *dvi_i_subconnector;
1398 
1399 	if (dev->mode_config.dvi_i_select_subconnector_property)
1400 		return 0;
1401 
1402 	dvi_i_selector =
1403 		drm_property_create_enum(dev, 0,
1404 				    "select subconnector",
1405 				    drm_dvi_i_select_enum_list,
1406 				    ARRAY_SIZE(drm_dvi_i_select_enum_list));
1407 	dev->mode_config.dvi_i_select_subconnector_property = dvi_i_selector;
1408 
1409 	dvi_i_subconnector = drm_property_create_enum(dev, DRM_MODE_PROP_IMMUTABLE,
1410 				    "subconnector",
1411 				    drm_dvi_i_subconnector_enum_list,
1412 				    ARRAY_SIZE(drm_dvi_i_subconnector_enum_list));
1413 	dev->mode_config.dvi_i_subconnector_property = dvi_i_subconnector;
1414 
1415 	return 0;
1416 }
1417 EXPORT_SYMBOL(drm_mode_create_dvi_i_properties);
1418 
1419 /**
1420  * drm_connector_attach_dp_subconnector_property - create subconnector property for DP
1421  * @connector: drm_connector to attach property
1422  *
1423  * Called by a driver when DP connector is created.
1424  */
1425 void drm_connector_attach_dp_subconnector_property(struct drm_connector *connector)
1426 {
1427 	struct drm_mode_config *mode_config = &connector->dev->mode_config;
1428 
1429 	if (!mode_config->dp_subconnector_property)
1430 		mode_config->dp_subconnector_property =
1431 			drm_property_create_enum(connector->dev,
1432 				DRM_MODE_PROP_IMMUTABLE,
1433 				"subconnector",
1434 				drm_dp_subconnector_enum_list,
1435 				ARRAY_SIZE(drm_dp_subconnector_enum_list));
1436 
1437 	drm_object_attach_property(&connector->base,
1438 				   mode_config->dp_subconnector_property,
1439 				   DRM_MODE_SUBCONNECTOR_Unknown);
1440 }
1441 EXPORT_SYMBOL(drm_connector_attach_dp_subconnector_property);
1442 
1443 /**
1444  * DOC: HDMI connector properties
1445  *
1446  * content type (HDMI specific):
1447  *	Indicates content type setting to be used in HDMI infoframes to indicate
1448  *	content type for the external device, so that it adjusts its display
1449  *	settings accordingly.
1450  *
1451  *	The value of this property can be one of the following:
1452  *
1453  *	No Data:
1454  *		Content type is unknown
1455  *	Graphics:
1456  *		Content type is graphics
1457  *	Photo:
1458  *		Content type is photo
1459  *	Cinema:
1460  *		Content type is cinema
1461  *	Game:
1462  *		Content type is game
1463  *
1464  *	The meaning of each content type is defined in CTA-861-G table 15.
1465  *
1466  *	Drivers can set up this property by calling
1467  *	drm_connector_attach_content_type_property(). Decoding to
1468  *	infoframe values is done through drm_hdmi_avi_infoframe_content_type().
1469  */
1470 
1471 /**
1472  * drm_connector_attach_content_type_property - attach content-type property
1473  * @connector: connector to attach content type property on.
1474  *
1475  * Called by a driver the first time a HDMI connector is made.
1476  *
1477  * Returns: %0
1478  */
1479 int drm_connector_attach_content_type_property(struct drm_connector *connector)
1480 {
1481 	if (!drm_mode_create_content_type_property(connector->dev))
1482 		drm_object_attach_property(&connector->base,
1483 					   connector->dev->mode_config.content_type_property,
1484 					   DRM_MODE_CONTENT_TYPE_NO_DATA);
1485 	return 0;
1486 }
1487 EXPORT_SYMBOL(drm_connector_attach_content_type_property);
1488 
1489 /**
1490  * drm_connector_attach_tv_margin_properties - attach TV connector margin
1491  * 	properties
1492  * @connector: DRM connector
1493  *
1494  * Called by a driver when it needs to attach TV margin props to a connector.
1495  * Typically used on SDTV and HDMI connectors.
1496  */
1497 void drm_connector_attach_tv_margin_properties(struct drm_connector *connector)
1498 {
1499 	struct drm_device *dev = connector->dev;
1500 
1501 	drm_object_attach_property(&connector->base,
1502 				   dev->mode_config.tv_left_margin_property,
1503 				   0);
1504 	drm_object_attach_property(&connector->base,
1505 				   dev->mode_config.tv_right_margin_property,
1506 				   0);
1507 	drm_object_attach_property(&connector->base,
1508 				   dev->mode_config.tv_top_margin_property,
1509 				   0);
1510 	drm_object_attach_property(&connector->base,
1511 				   dev->mode_config.tv_bottom_margin_property,
1512 				   0);
1513 }
1514 EXPORT_SYMBOL(drm_connector_attach_tv_margin_properties);
1515 
1516 /**
1517  * drm_mode_create_tv_margin_properties - create TV connector margin properties
1518  * @dev: DRM device
1519  *
1520  * Called by a driver's HDMI connector initialization routine, this function
1521  * creates the TV margin properties for a given device. No need to call this
1522  * function for an SDTV connector, it's already called from
1523  * drm_mode_create_tv_properties().
1524  *
1525  * Returns:
1526  * 0 on success or a negative error code on failure.
1527  */
1528 int drm_mode_create_tv_margin_properties(struct drm_device *dev)
1529 {
1530 	if (dev->mode_config.tv_left_margin_property)
1531 		return 0;
1532 
1533 	dev->mode_config.tv_left_margin_property =
1534 		drm_property_create_range(dev, 0, "left margin", 0, 100);
1535 	if (!dev->mode_config.tv_left_margin_property)
1536 		return -ENOMEM;
1537 
1538 	dev->mode_config.tv_right_margin_property =
1539 		drm_property_create_range(dev, 0, "right margin", 0, 100);
1540 	if (!dev->mode_config.tv_right_margin_property)
1541 		return -ENOMEM;
1542 
1543 	dev->mode_config.tv_top_margin_property =
1544 		drm_property_create_range(dev, 0, "top margin", 0, 100);
1545 	if (!dev->mode_config.tv_top_margin_property)
1546 		return -ENOMEM;
1547 
1548 	dev->mode_config.tv_bottom_margin_property =
1549 		drm_property_create_range(dev, 0, "bottom margin", 0, 100);
1550 	if (!dev->mode_config.tv_bottom_margin_property)
1551 		return -ENOMEM;
1552 
1553 	return 0;
1554 }
1555 EXPORT_SYMBOL(drm_mode_create_tv_margin_properties);
1556 
1557 /**
1558  * drm_mode_create_tv_properties - create TV specific connector properties
1559  * @dev: DRM device
1560  * @num_modes: number of different TV formats (modes) supported
1561  * @modes: array of pointers to strings containing name of each format
1562  *
1563  * Called by a driver's TV initialization routine, this function creates
1564  * the TV specific connector properties for a given device.  Caller is
1565  * responsible for allocating a list of format names and passing them to
1566  * this routine.
1567  *
1568  * Returns:
1569  * 0 on success or a negative error code on failure.
1570  */
1571 int drm_mode_create_tv_properties(struct drm_device *dev,
1572 				  unsigned int num_modes,
1573 				  const char * const modes[])
1574 {
1575 	struct drm_property *tv_selector;
1576 	struct drm_property *tv_subconnector;
1577 	unsigned int i;
1578 
1579 	if (dev->mode_config.tv_select_subconnector_property)
1580 		return 0;
1581 
1582 	/*
1583 	 * Basic connector properties
1584 	 */
1585 	tv_selector = drm_property_create_enum(dev, 0,
1586 					  "select subconnector",
1587 					  drm_tv_select_enum_list,
1588 					  ARRAY_SIZE(drm_tv_select_enum_list));
1589 	if (!tv_selector)
1590 		goto nomem;
1591 
1592 	dev->mode_config.tv_select_subconnector_property = tv_selector;
1593 
1594 	tv_subconnector =
1595 		drm_property_create_enum(dev, DRM_MODE_PROP_IMMUTABLE,
1596 				    "subconnector",
1597 				    drm_tv_subconnector_enum_list,
1598 				    ARRAY_SIZE(drm_tv_subconnector_enum_list));
1599 	if (!tv_subconnector)
1600 		goto nomem;
1601 	dev->mode_config.tv_subconnector_property = tv_subconnector;
1602 
1603 	/*
1604 	 * Other, TV specific properties: margins & TV modes.
1605 	 */
1606 	if (drm_mode_create_tv_margin_properties(dev))
1607 		goto nomem;
1608 
1609 	dev->mode_config.tv_mode_property =
1610 		drm_property_create(dev, DRM_MODE_PROP_ENUM,
1611 				    "mode", num_modes);
1612 	if (!dev->mode_config.tv_mode_property)
1613 		goto nomem;
1614 
1615 	for (i = 0; i < num_modes; i++)
1616 		drm_property_add_enum(dev->mode_config.tv_mode_property,
1617 				      i, modes[i]);
1618 
1619 	dev->mode_config.tv_brightness_property =
1620 		drm_property_create_range(dev, 0, "brightness", 0, 100);
1621 	if (!dev->mode_config.tv_brightness_property)
1622 		goto nomem;
1623 
1624 	dev->mode_config.tv_contrast_property =
1625 		drm_property_create_range(dev, 0, "contrast", 0, 100);
1626 	if (!dev->mode_config.tv_contrast_property)
1627 		goto nomem;
1628 
1629 	dev->mode_config.tv_flicker_reduction_property =
1630 		drm_property_create_range(dev, 0, "flicker reduction", 0, 100);
1631 	if (!dev->mode_config.tv_flicker_reduction_property)
1632 		goto nomem;
1633 
1634 	dev->mode_config.tv_overscan_property =
1635 		drm_property_create_range(dev, 0, "overscan", 0, 100);
1636 	if (!dev->mode_config.tv_overscan_property)
1637 		goto nomem;
1638 
1639 	dev->mode_config.tv_saturation_property =
1640 		drm_property_create_range(dev, 0, "saturation", 0, 100);
1641 	if (!dev->mode_config.tv_saturation_property)
1642 		goto nomem;
1643 
1644 	dev->mode_config.tv_hue_property =
1645 		drm_property_create_range(dev, 0, "hue", 0, 100);
1646 	if (!dev->mode_config.tv_hue_property)
1647 		goto nomem;
1648 
1649 	return 0;
1650 nomem:
1651 	return -ENOMEM;
1652 }
1653 EXPORT_SYMBOL(drm_mode_create_tv_properties);
1654 
1655 /**
1656  * drm_mode_create_scaling_mode_property - create scaling mode property
1657  * @dev: DRM device
1658  *
1659  * Called by a driver the first time it's needed, must be attached to desired
1660  * connectors.
1661  *
1662  * Atomic drivers should use drm_connector_attach_scaling_mode_property()
1663  * instead to correctly assign &drm_connector_state.scaling_mode
1664  * in the atomic state.
1665  *
1666  * Returns: %0
1667  */
1668 int drm_mode_create_scaling_mode_property(struct drm_device *dev)
1669 {
1670 	struct drm_property *scaling_mode;
1671 
1672 	if (dev->mode_config.scaling_mode_property)
1673 		return 0;
1674 
1675 	scaling_mode =
1676 		drm_property_create_enum(dev, 0, "scaling mode",
1677 				drm_scaling_mode_enum_list,
1678 				    ARRAY_SIZE(drm_scaling_mode_enum_list));
1679 
1680 	dev->mode_config.scaling_mode_property = scaling_mode;
1681 
1682 	return 0;
1683 }
1684 EXPORT_SYMBOL(drm_mode_create_scaling_mode_property);
1685 
1686 /**
1687  * DOC: Variable refresh properties
1688  *
1689  * Variable refresh rate capable displays can dynamically adjust their
1690  * refresh rate by extending the duration of their vertical front porch
1691  * until page flip or timeout occurs. This can reduce or remove stuttering
1692  * and latency in scenarios where the page flip does not align with the
1693  * vblank interval.
1694  *
1695  * An example scenario would be an application flipping at a constant rate
1696  * of 48Hz on a 60Hz display. The page flip will frequently miss the vblank
1697  * interval and the same contents will be displayed twice. This can be
1698  * observed as stuttering for content with motion.
1699  *
1700  * If variable refresh rate was active on a display that supported a
1701  * variable refresh range from 35Hz to 60Hz no stuttering would be observable
1702  * for the example scenario. The minimum supported variable refresh rate of
1703  * 35Hz is below the page flip frequency and the vertical front porch can
1704  * be extended until the page flip occurs. The vblank interval will be
1705  * directly aligned to the page flip rate.
1706  *
1707  * Not all userspace content is suitable for use with variable refresh rate.
1708  * Large and frequent changes in vertical front porch duration may worsen
1709  * perceived stuttering for input sensitive applications.
1710  *
1711  * Panel brightness will also vary with vertical front porch duration. Some
1712  * panels may have noticeable differences in brightness between the minimum
1713  * vertical front porch duration and the maximum vertical front porch duration.
1714  * Large and frequent changes in vertical front porch duration may produce
1715  * observable flickering for such panels.
1716  *
1717  * Userspace control for variable refresh rate is supported via properties
1718  * on the &drm_connector and &drm_crtc objects.
1719  *
1720  * "vrr_capable":
1721  *	Optional &drm_connector boolean property that drivers should attach
1722  *	with drm_connector_attach_vrr_capable_property() on connectors that
1723  *	could support variable refresh rates. Drivers should update the
1724  *	property value by calling drm_connector_set_vrr_capable_property().
1725  *
1726  *	Absence of the property should indicate absence of support.
1727  *
1728  * "VRR_ENABLED":
1729  *	Default &drm_crtc boolean property that notifies the driver that the
1730  *	content on the CRTC is suitable for variable refresh rate presentation.
1731  *	The driver will take this property as a hint to enable variable
1732  *	refresh rate support if the receiver supports it, ie. if the
1733  *	"vrr_capable" property is true on the &drm_connector object. The
1734  *	vertical front porch duration will be extended until page-flip or
1735  *	timeout when enabled.
1736  *
1737  *	The minimum vertical front porch duration is defined as the vertical
1738  *	front porch duration for the current mode.
1739  *
1740  *	The maximum vertical front porch duration is greater than or equal to
1741  *	the minimum vertical front porch duration. The duration is derived
1742  *	from the minimum supported variable refresh rate for the connector.
1743  *
1744  *	The driver may place further restrictions within these minimum
1745  *	and maximum bounds.
1746  */
1747 
1748 /**
1749  * drm_connector_attach_vrr_capable_property - creates the
1750  * vrr_capable property
1751  * @connector: connector to create the vrr_capable property on.
1752  *
1753  * This is used by atomic drivers to add support for querying
1754  * variable refresh rate capability for a connector.
1755  *
1756  * Returns:
1757  * Zero on success, negative errno on failure.
1758  */
1759 int drm_connector_attach_vrr_capable_property(
1760 	struct drm_connector *connector)
1761 {
1762 	struct drm_device *dev = connector->dev;
1763 	struct drm_property *prop;
1764 
1765 	if (!connector->vrr_capable_property) {
1766 		prop = drm_property_create_bool(dev, DRM_MODE_PROP_IMMUTABLE,
1767 			"vrr_capable");
1768 		if (!prop)
1769 			return -ENOMEM;
1770 
1771 		connector->vrr_capable_property = prop;
1772 		drm_object_attach_property(&connector->base, prop, 0);
1773 	}
1774 
1775 	return 0;
1776 }
1777 EXPORT_SYMBOL(drm_connector_attach_vrr_capable_property);
1778 
1779 /**
1780  * drm_connector_attach_scaling_mode_property - attach atomic scaling mode property
1781  * @connector: connector to attach scaling mode property on.
1782  * @scaling_mode_mask: or'ed mask of BIT(%DRM_MODE_SCALE_\*).
1783  *
1784  * This is used to add support for scaling mode to atomic drivers.
1785  * The scaling mode will be set to &drm_connector_state.scaling_mode
1786  * and can be used from &drm_connector_helper_funcs->atomic_check for validation.
1787  *
1788  * This is the atomic version of drm_mode_create_scaling_mode_property().
1789  *
1790  * Returns:
1791  * Zero on success, negative errno on failure.
1792  */
1793 int drm_connector_attach_scaling_mode_property(struct drm_connector *connector,
1794 					       u32 scaling_mode_mask)
1795 {
1796 	struct drm_device *dev = connector->dev;
1797 	struct drm_property *scaling_mode_property;
1798 	int i;
1799 	const unsigned valid_scaling_mode_mask =
1800 		(1U << ARRAY_SIZE(drm_scaling_mode_enum_list)) - 1;
1801 
1802 	if (WARN_ON(hweight32(scaling_mode_mask) < 2 ||
1803 		    scaling_mode_mask & ~valid_scaling_mode_mask))
1804 		return -EINVAL;
1805 
1806 	scaling_mode_property =
1807 		drm_property_create(dev, DRM_MODE_PROP_ENUM, "scaling mode",
1808 				    hweight32(scaling_mode_mask));
1809 
1810 	if (!scaling_mode_property)
1811 		return -ENOMEM;
1812 
1813 	for (i = 0; i < ARRAY_SIZE(drm_scaling_mode_enum_list); i++) {
1814 		int ret;
1815 
1816 		if (!(BIT(i) & scaling_mode_mask))
1817 			continue;
1818 
1819 		ret = drm_property_add_enum(scaling_mode_property,
1820 					    drm_scaling_mode_enum_list[i].type,
1821 					    drm_scaling_mode_enum_list[i].name);
1822 
1823 		if (ret) {
1824 			drm_property_destroy(dev, scaling_mode_property);
1825 
1826 			return ret;
1827 		}
1828 	}
1829 
1830 	drm_object_attach_property(&connector->base,
1831 				   scaling_mode_property, 0);
1832 
1833 	connector->scaling_mode_property = scaling_mode_property;
1834 
1835 	return 0;
1836 }
1837 EXPORT_SYMBOL(drm_connector_attach_scaling_mode_property);
1838 
1839 /**
1840  * drm_mode_create_aspect_ratio_property - create aspect ratio property
1841  * @dev: DRM device
1842  *
1843  * Called by a driver the first time it's needed, must be attached to desired
1844  * connectors.
1845  *
1846  * Returns:
1847  * Zero on success, negative errno on failure.
1848  */
1849 int drm_mode_create_aspect_ratio_property(struct drm_device *dev)
1850 {
1851 	if (dev->mode_config.aspect_ratio_property)
1852 		return 0;
1853 
1854 	dev->mode_config.aspect_ratio_property =
1855 		drm_property_create_enum(dev, 0, "aspect ratio",
1856 				drm_aspect_ratio_enum_list,
1857 				ARRAY_SIZE(drm_aspect_ratio_enum_list));
1858 
1859 	if (dev->mode_config.aspect_ratio_property == NULL)
1860 		return -ENOMEM;
1861 
1862 	return 0;
1863 }
1864 EXPORT_SYMBOL(drm_mode_create_aspect_ratio_property);
1865 
1866 /**
1867  * DOC: standard connector properties
1868  *
1869  * Colorspace:
1870  *     This property helps select a suitable colorspace based on the sink
1871  *     capability. Modern sink devices support wider gamut like BT2020.
1872  *     This helps switch to BT2020 mode if the BT2020 encoded video stream
1873  *     is being played by the user, same for any other colorspace. Thereby
1874  *     giving a good visual experience to users.
1875  *
1876  *     The expectation from userspace is that it should parse the EDID
1877  *     and get supported colorspaces. Use this property and switch to the
1878  *     one supported. Sink supported colorspaces should be retrieved by
1879  *     userspace from EDID and driver will not explicitly expose them.
1880  *
1881  *     Basically the expectation from userspace is:
1882  *      - Set up CRTC DEGAMMA/CTM/GAMMA to convert to some sink
1883  *        colorspace
1884  *      - Set this new property to let the sink know what it
1885  *        converted the CRTC output to.
1886  *      - This property is just to inform sink what colorspace
1887  *        source is trying to drive.
1888  *
1889  * Because between HDMI and DP have different colorspaces,
1890  * drm_mode_create_hdmi_colorspace_property() is used for HDMI connector and
1891  * drm_mode_create_dp_colorspace_property() is used for DP connector.
1892  */
1893 
1894 /**
1895  * drm_mode_create_hdmi_colorspace_property - create hdmi colorspace property
1896  * @connector: connector to create the Colorspace property on.
1897  *
1898  * Called by a driver the first time it's needed, must be attached to desired
1899  * HDMI connectors.
1900  *
1901  * Returns:
1902  * Zero on success, negative errno on failure.
1903  */
1904 int drm_mode_create_hdmi_colorspace_property(struct drm_connector *connector)
1905 {
1906 	struct drm_device *dev = connector->dev;
1907 
1908 	if (connector->colorspace_property)
1909 		return 0;
1910 
1911 	connector->colorspace_property =
1912 		drm_property_create_enum(dev, DRM_MODE_PROP_ENUM, "Colorspace",
1913 					 hdmi_colorspaces,
1914 					 ARRAY_SIZE(hdmi_colorspaces));
1915 
1916 	if (!connector->colorspace_property)
1917 		return -ENOMEM;
1918 
1919 	return 0;
1920 }
1921 EXPORT_SYMBOL(drm_mode_create_hdmi_colorspace_property);
1922 
1923 /**
1924  * drm_mode_create_dp_colorspace_property - create dp colorspace property
1925  * @connector: connector to create the Colorspace property on.
1926  *
1927  * Called by a driver the first time it's needed, must be attached to desired
1928  * DP connectors.
1929  *
1930  * Returns:
1931  * Zero on success, negative errno on failure.
1932  */
1933 int drm_mode_create_dp_colorspace_property(struct drm_connector *connector)
1934 {
1935 	struct drm_device *dev = connector->dev;
1936 
1937 	if (connector->colorspace_property)
1938 		return 0;
1939 
1940 	connector->colorspace_property =
1941 		drm_property_create_enum(dev, DRM_MODE_PROP_ENUM, "Colorspace",
1942 					 dp_colorspaces,
1943 					 ARRAY_SIZE(dp_colorspaces));
1944 
1945 	if (!connector->colorspace_property)
1946 		return -ENOMEM;
1947 
1948 	return 0;
1949 }
1950 EXPORT_SYMBOL(drm_mode_create_dp_colorspace_property);
1951 
1952 /**
1953  * drm_mode_create_content_type_property - create content type property
1954  * @dev: DRM device
1955  *
1956  * Called by a driver the first time it's needed, must be attached to desired
1957  * connectors.
1958  *
1959  * Returns:
1960  * Zero on success, negative errno on failure.
1961  */
1962 int drm_mode_create_content_type_property(struct drm_device *dev)
1963 {
1964 	if (dev->mode_config.content_type_property)
1965 		return 0;
1966 
1967 	dev->mode_config.content_type_property =
1968 		drm_property_create_enum(dev, 0, "content type",
1969 					 drm_content_type_enum_list,
1970 					 ARRAY_SIZE(drm_content_type_enum_list));
1971 
1972 	if (dev->mode_config.content_type_property == NULL)
1973 		return -ENOMEM;
1974 
1975 	return 0;
1976 }
1977 EXPORT_SYMBOL(drm_mode_create_content_type_property);
1978 
1979 /**
1980  * drm_mode_create_suggested_offset_properties - create suggests offset properties
1981  * @dev: DRM device
1982  *
1983  * Create the suggested x/y offset property for connectors.
1984  *
1985  * Returns:
1986  * 0 on success or a negative error code on failure.
1987  */
1988 int drm_mode_create_suggested_offset_properties(struct drm_device *dev)
1989 {
1990 	if (dev->mode_config.suggested_x_property && dev->mode_config.suggested_y_property)
1991 		return 0;
1992 
1993 	dev->mode_config.suggested_x_property =
1994 		drm_property_create_range(dev, DRM_MODE_PROP_IMMUTABLE, "suggested X", 0, 0xffffffff);
1995 
1996 	dev->mode_config.suggested_y_property =
1997 		drm_property_create_range(dev, DRM_MODE_PROP_IMMUTABLE, "suggested Y", 0, 0xffffffff);
1998 
1999 	if (dev->mode_config.suggested_x_property == NULL ||
2000 	    dev->mode_config.suggested_y_property == NULL)
2001 		return -ENOMEM;
2002 	return 0;
2003 }
2004 EXPORT_SYMBOL(drm_mode_create_suggested_offset_properties);
2005 
2006 /**
2007  * drm_connector_set_path_property - set tile property on connector
2008  * @connector: connector to set property on.
2009  * @path: path to use for property; must not be NULL.
2010  *
2011  * This creates a property to expose to userspace to specify a
2012  * connector path. This is mainly used for DisplayPort MST where
2013  * connectors have a topology and we want to allow userspace to give
2014  * them more meaningful names.
2015  *
2016  * Returns:
2017  * Zero on success, negative errno on failure.
2018  */
2019 int drm_connector_set_path_property(struct drm_connector *connector,
2020 				    const char *path)
2021 {
2022 	struct drm_device *dev = connector->dev;
2023 	int ret;
2024 
2025 	ret = drm_property_replace_global_blob(dev,
2026 					       &connector->path_blob_ptr,
2027 					       strlen(path) + 1,
2028 					       path,
2029 					       &connector->base,
2030 					       dev->mode_config.path_property);
2031 	return ret;
2032 }
2033 EXPORT_SYMBOL(drm_connector_set_path_property);
2034 
2035 /**
2036  * drm_connector_set_tile_property - set tile property on connector
2037  * @connector: connector to set property on.
2038  *
2039  * This looks up the tile information for a connector, and creates a
2040  * property for userspace to parse if it exists. The property is of
2041  * the form of 8 integers using ':' as a separator.
2042  * This is used for dual port tiled displays with DisplayPort SST
2043  * or DisplayPort MST connectors.
2044  *
2045  * Returns:
2046  * Zero on success, errno on failure.
2047  */
2048 int drm_connector_set_tile_property(struct drm_connector *connector)
2049 {
2050 	struct drm_device *dev = connector->dev;
2051 	char tile[256];
2052 	int ret;
2053 
2054 	if (!connector->has_tile) {
2055 		ret  = drm_property_replace_global_blob(dev,
2056 							&connector->tile_blob_ptr,
2057 							0,
2058 							NULL,
2059 							&connector->base,
2060 							dev->mode_config.tile_property);
2061 		return ret;
2062 	}
2063 
2064 	snprintf(tile, 256, "%d:%d:%d:%d:%d:%d:%d:%d",
2065 		 connector->tile_group->id, connector->tile_is_single_monitor,
2066 		 connector->num_h_tile, connector->num_v_tile,
2067 		 connector->tile_h_loc, connector->tile_v_loc,
2068 		 connector->tile_h_size, connector->tile_v_size);
2069 
2070 	ret = drm_property_replace_global_blob(dev,
2071 					       &connector->tile_blob_ptr,
2072 					       strlen(tile) + 1,
2073 					       tile,
2074 					       &connector->base,
2075 					       dev->mode_config.tile_property);
2076 	return ret;
2077 }
2078 EXPORT_SYMBOL(drm_connector_set_tile_property);
2079 
2080 /**
2081  * drm_connector_update_edid_property - update the edid property of a connector
2082  * @connector: drm connector
2083  * @edid: new value of the edid property
2084  *
2085  * This function creates a new blob modeset object and assigns its id to the
2086  * connector's edid property.
2087  * Since we also parse tile information from EDID's displayID block, we also
2088  * set the connector's tile property here. See drm_connector_set_tile_property()
2089  * for more details.
2090  *
2091  * Returns:
2092  * Zero on success, negative errno on failure.
2093  */
2094 int drm_connector_update_edid_property(struct drm_connector *connector,
2095 				       const struct edid *edid)
2096 {
2097 	struct drm_device *dev = connector->dev;
2098 	size_t size = 0;
2099 	int ret;
2100 	const struct edid *old_edid;
2101 
2102 	/* ignore requests to set edid when overridden */
2103 	if (connector->override_edid)
2104 		return 0;
2105 
2106 	if (edid)
2107 		size = EDID_LENGTH * (1 + edid->extensions);
2108 
2109 	/* Set the display info, using edid if available, otherwise
2110 	 * resetting the values to defaults. This duplicates the work
2111 	 * done in drm_add_edid_modes, but that function is not
2112 	 * consistently called before this one in all drivers and the
2113 	 * computation is cheap enough that it seems better to
2114 	 * duplicate it rather than attempt to ensure some arbitrary
2115 	 * ordering of calls.
2116 	 */
2117 	if (edid)
2118 		drm_add_display_info(connector, edid);
2119 	else
2120 		drm_reset_display_info(connector);
2121 
2122 	drm_update_tile_info(connector, edid);
2123 
2124 	if (connector->edid_blob_ptr) {
2125 		old_edid = (const struct edid *)connector->edid_blob_ptr->data;
2126 		if (old_edid) {
2127 			if (!drm_edid_are_equal(edid, old_edid)) {
2128 				DRM_DEBUG_KMS("[CONNECTOR:%d:%s] Edid was changed.\n",
2129 					      connector->base.id, connector->name);
2130 
2131 				connector->epoch_counter += 1;
2132 				DRM_DEBUG_KMS("Updating change counter to %llu\n",
2133 					      connector->epoch_counter);
2134 			}
2135 		}
2136 	}
2137 
2138 	drm_object_property_set_value(&connector->base,
2139 				      dev->mode_config.non_desktop_property,
2140 				      connector->display_info.non_desktop);
2141 
2142 	ret = drm_property_replace_global_blob(dev,
2143 					       &connector->edid_blob_ptr,
2144 					       size,
2145 					       edid,
2146 					       &connector->base,
2147 					       dev->mode_config.edid_property);
2148 	if (ret)
2149 		return ret;
2150 	return drm_connector_set_tile_property(connector);
2151 }
2152 EXPORT_SYMBOL(drm_connector_update_edid_property);
2153 
2154 /**
2155  * drm_connector_set_link_status_property - Set link status property of a connector
2156  * @connector: drm connector
2157  * @link_status: new value of link status property (0: Good, 1: Bad)
2158  *
2159  * In usual working scenario, this link status property will always be set to
2160  * "GOOD". If something fails during or after a mode set, the kernel driver
2161  * may set this link status property to "BAD". The caller then needs to send a
2162  * hotplug uevent for userspace to re-check the valid modes through
2163  * GET_CONNECTOR_IOCTL and retry modeset.
2164  *
2165  * Note: Drivers cannot rely on userspace to support this property and
2166  * issue a modeset. As such, they may choose to handle issues (like
2167  * re-training a link) without userspace's intervention.
2168  *
2169  * The reason for adding this property is to handle link training failures, but
2170  * it is not limited to DP or link training. For example, if we implement
2171  * asynchronous setcrtc, this property can be used to report any failures in that.
2172  */
2173 void drm_connector_set_link_status_property(struct drm_connector *connector,
2174 					    uint64_t link_status)
2175 {
2176 	struct drm_device *dev = connector->dev;
2177 
2178 	drm_modeset_lock(&dev->mode_config.connection_mutex, NULL);
2179 	connector->state->link_status = link_status;
2180 	drm_modeset_unlock(&dev->mode_config.connection_mutex);
2181 }
2182 EXPORT_SYMBOL(drm_connector_set_link_status_property);
2183 
2184 /**
2185  * drm_connector_attach_max_bpc_property - attach "max bpc" property
2186  * @connector: connector to attach max bpc property on.
2187  * @min: The minimum bit depth supported by the connector.
2188  * @max: The maximum bit depth supported by the connector.
2189  *
2190  * This is used to add support for limiting the bit depth on a connector.
2191  *
2192  * Returns:
2193  * Zero on success, negative errno on failure.
2194  */
2195 int drm_connector_attach_max_bpc_property(struct drm_connector *connector,
2196 					  int min, int max)
2197 {
2198 	struct drm_device *dev = connector->dev;
2199 	struct drm_property *prop;
2200 
2201 	prop = connector->max_bpc_property;
2202 	if (!prop) {
2203 		prop = drm_property_create_range(dev, 0, "max bpc", min, max);
2204 		if (!prop)
2205 			return -ENOMEM;
2206 
2207 		connector->max_bpc_property = prop;
2208 	}
2209 
2210 	drm_object_attach_property(&connector->base, prop, max);
2211 	connector->state->max_requested_bpc = max;
2212 	connector->state->max_bpc = max;
2213 
2214 	return 0;
2215 }
2216 EXPORT_SYMBOL(drm_connector_attach_max_bpc_property);
2217 
2218 /**
2219  * drm_connector_attach_hdr_output_metadata_property - attach "HDR_OUTPUT_METADA" property
2220  * @connector: connector to attach the property on.
2221  *
2222  * This is used to allow the userspace to send HDR Metadata to the
2223  * driver.
2224  *
2225  * Returns:
2226  * Zero on success, negative errno on failure.
2227  */
2228 int drm_connector_attach_hdr_output_metadata_property(struct drm_connector *connector)
2229 {
2230 	struct drm_device *dev = connector->dev;
2231 	struct drm_property *prop = dev->mode_config.hdr_output_metadata_property;
2232 
2233 	drm_object_attach_property(&connector->base, prop, 0);
2234 
2235 	return 0;
2236 }
2237 EXPORT_SYMBOL(drm_connector_attach_hdr_output_metadata_property);
2238 
2239 /**
2240  * drm_connector_attach_colorspace_property - attach "Colorspace" property
2241  * @connector: connector to attach the property on.
2242  *
2243  * This is used to allow the userspace to signal the output colorspace
2244  * to the driver.
2245  *
2246  * Returns:
2247  * Zero on success, negative errno on failure.
2248  */
2249 int drm_connector_attach_colorspace_property(struct drm_connector *connector)
2250 {
2251 	struct drm_property *prop = connector->colorspace_property;
2252 
2253 	drm_object_attach_property(&connector->base, prop, DRM_MODE_COLORIMETRY_DEFAULT);
2254 
2255 	return 0;
2256 }
2257 EXPORT_SYMBOL(drm_connector_attach_colorspace_property);
2258 
2259 /**
2260  * drm_connector_atomic_hdr_metadata_equal - checks if the hdr metadata changed
2261  * @old_state: old connector state to compare
2262  * @new_state: new connector state to compare
2263  *
2264  * This is used by HDR-enabled drivers to test whether the HDR metadata
2265  * have changed between two different connector state (and thus probably
2266  * requires a full blown mode change).
2267  *
2268  * Returns:
2269  * True if the metadata are equal, False otherwise
2270  */
2271 bool drm_connector_atomic_hdr_metadata_equal(struct drm_connector_state *old_state,
2272 					     struct drm_connector_state *new_state)
2273 {
2274 	struct drm_property_blob *old_blob = old_state->hdr_output_metadata;
2275 	struct drm_property_blob *new_blob = new_state->hdr_output_metadata;
2276 
2277 	if (!old_blob || !new_blob)
2278 		return old_blob == new_blob;
2279 
2280 	if (old_blob->length != new_blob->length)
2281 		return false;
2282 
2283 	return !memcmp(old_blob->data, new_blob->data, old_blob->length);
2284 }
2285 EXPORT_SYMBOL(drm_connector_atomic_hdr_metadata_equal);
2286 
2287 /**
2288  * drm_connector_set_vrr_capable_property - sets the variable refresh rate
2289  * capable property for a connector
2290  * @connector: drm connector
2291  * @capable: True if the connector is variable refresh rate capable
2292  *
2293  * Should be used by atomic drivers to update the indicated support for
2294  * variable refresh rate over a connector.
2295  */
2296 void drm_connector_set_vrr_capable_property(
2297 		struct drm_connector *connector, bool capable)
2298 {
2299 	if (!connector->vrr_capable_property)
2300 		return;
2301 
2302 	drm_object_property_set_value(&connector->base,
2303 				      connector->vrr_capable_property,
2304 				      capable);
2305 }
2306 EXPORT_SYMBOL(drm_connector_set_vrr_capable_property);
2307 
2308 /**
2309  * drm_connector_set_panel_orientation - sets the connector's panel_orientation
2310  * @connector: connector for which to set the panel-orientation property.
2311  * @panel_orientation: drm_panel_orientation value to set
2312  *
2313  * This function sets the connector's panel_orientation and attaches
2314  * a "panel orientation" property to the connector.
2315  *
2316  * Calling this function on a connector where the panel_orientation has
2317  * already been set is a no-op (e.g. the orientation has been overridden with
2318  * a kernel commandline option).
2319  *
2320  * It is allowed to call this function with a panel_orientation of
2321  * DRM_MODE_PANEL_ORIENTATION_UNKNOWN, in which case it is a no-op.
2322  *
2323  * Returns:
2324  * Zero on success, negative errno on failure.
2325  */
2326 int drm_connector_set_panel_orientation(
2327 	struct drm_connector *connector,
2328 	enum drm_panel_orientation panel_orientation)
2329 {
2330 	struct drm_device *dev = connector->dev;
2331 	struct drm_display_info *info = &connector->display_info;
2332 	struct drm_property *prop;
2333 
2334 	/* Already set? */
2335 	if (info->panel_orientation != DRM_MODE_PANEL_ORIENTATION_UNKNOWN)
2336 		return 0;
2337 
2338 	/* Don't attach the property if the orientation is unknown */
2339 	if (panel_orientation == DRM_MODE_PANEL_ORIENTATION_UNKNOWN)
2340 		return 0;
2341 
2342 	info->panel_orientation = panel_orientation;
2343 
2344 	prop = dev->mode_config.panel_orientation_property;
2345 	if (!prop) {
2346 		prop = drm_property_create_enum(dev, DRM_MODE_PROP_IMMUTABLE,
2347 				"panel orientation",
2348 				drm_panel_orientation_enum_list,
2349 				ARRAY_SIZE(drm_panel_orientation_enum_list));
2350 		if (!prop)
2351 			return -ENOMEM;
2352 
2353 		dev->mode_config.panel_orientation_property = prop;
2354 	}
2355 
2356 	drm_object_attach_property(&connector->base, prop,
2357 				   info->panel_orientation);
2358 	return 0;
2359 }
2360 EXPORT_SYMBOL(drm_connector_set_panel_orientation);
2361 
2362 /**
2363  * drm_connector_set_panel_orientation_with_quirk - set the
2364  *	connector's panel_orientation after checking for quirks
2365  * @connector: connector for which to init the panel-orientation property.
2366  * @panel_orientation: drm_panel_orientation value to set
2367  * @width: width in pixels of the panel, used for panel quirk detection
2368  * @height: height in pixels of the panel, used for panel quirk detection
2369  *
2370  * Like drm_connector_set_panel_orientation(), but with a check for platform
2371  * specific (e.g. DMI based) quirks overriding the passed in panel_orientation.
2372  *
2373  * Returns:
2374  * Zero on success, negative errno on failure.
2375  */
2376 int drm_connector_set_panel_orientation_with_quirk(
2377 	struct drm_connector *connector,
2378 	enum drm_panel_orientation panel_orientation,
2379 	int width, int height)
2380 {
2381 	int orientation_quirk;
2382 
2383 	orientation_quirk = drm_get_panel_orientation_quirk(width, height);
2384 	if (orientation_quirk != DRM_MODE_PANEL_ORIENTATION_UNKNOWN)
2385 		panel_orientation = orientation_quirk;
2386 
2387 	return drm_connector_set_panel_orientation(connector,
2388 						   panel_orientation);
2389 }
2390 EXPORT_SYMBOL(drm_connector_set_panel_orientation_with_quirk);
2391 
2392 static const struct drm_prop_enum_list privacy_screen_enum[] = {
2393 	{ PRIVACY_SCREEN_DISABLED,		"Disabled" },
2394 	{ PRIVACY_SCREEN_ENABLED,		"Enabled" },
2395 	{ PRIVACY_SCREEN_DISABLED_LOCKED,	"Disabled-locked" },
2396 	{ PRIVACY_SCREEN_ENABLED_LOCKED,	"Enabled-locked" },
2397 };
2398 
2399 /**
2400  * drm_connector_create_privacy_screen_properties - create the drm connecter's
2401  *    privacy-screen properties.
2402  * @connector: connector for which to create the privacy-screen properties
2403  *
2404  * This function creates the "privacy-screen sw-state" and "privacy-screen
2405  * hw-state" properties for the connector. They are not attached.
2406  */
2407 void
2408 drm_connector_create_privacy_screen_properties(struct drm_connector *connector)
2409 {
2410 	if (connector->privacy_screen_sw_state_property)
2411 		return;
2412 
2413 	/* Note sw-state only supports the first 2 values of the enum */
2414 	connector->privacy_screen_sw_state_property =
2415 		drm_property_create_enum(connector->dev, DRM_MODE_PROP_ENUM,
2416 				"privacy-screen sw-state",
2417 				privacy_screen_enum, 2);
2418 
2419 	connector->privacy_screen_hw_state_property =
2420 		drm_property_create_enum(connector->dev,
2421 				DRM_MODE_PROP_IMMUTABLE | DRM_MODE_PROP_ENUM,
2422 				"privacy-screen hw-state",
2423 				privacy_screen_enum,
2424 				ARRAY_SIZE(privacy_screen_enum));
2425 }
2426 EXPORT_SYMBOL(drm_connector_create_privacy_screen_properties);
2427 
2428 /**
2429  * drm_connector_attach_privacy_screen_properties - attach the drm connecter's
2430  *    privacy-screen properties.
2431  * @connector: connector on which to attach the privacy-screen properties
2432  *
2433  * This function attaches the "privacy-screen sw-state" and "privacy-screen
2434  * hw-state" properties to the connector. The initial state of both is set
2435  * to "Disabled".
2436  */
2437 void
2438 drm_connector_attach_privacy_screen_properties(struct drm_connector *connector)
2439 {
2440 	if (!connector->privacy_screen_sw_state_property)
2441 		return;
2442 
2443 	drm_object_attach_property(&connector->base,
2444 				   connector->privacy_screen_sw_state_property,
2445 				   PRIVACY_SCREEN_DISABLED);
2446 
2447 	drm_object_attach_property(&connector->base,
2448 				   connector->privacy_screen_hw_state_property,
2449 				   PRIVACY_SCREEN_DISABLED);
2450 }
2451 EXPORT_SYMBOL(drm_connector_attach_privacy_screen_properties);
2452 
2453 static void drm_connector_update_privacy_screen_properties(
2454 	struct drm_connector *connector, bool set_sw_state)
2455 {
2456 	enum drm_privacy_screen_status sw_state, hw_state;
2457 
2458 	drm_privacy_screen_get_state(connector->privacy_screen,
2459 				     &sw_state, &hw_state);
2460 
2461 	if (set_sw_state)
2462 		connector->state->privacy_screen_sw_state = sw_state;
2463 	drm_object_property_set_value(&connector->base,
2464 			connector->privacy_screen_hw_state_property, hw_state);
2465 }
2466 
2467 static int drm_connector_privacy_screen_notifier(
2468 	struct notifier_block *nb, unsigned long action, void *data)
2469 {
2470 	struct drm_connector *connector =
2471 		container_of(nb, struct drm_connector, privacy_screen_notifier);
2472 	struct drm_device *dev = connector->dev;
2473 
2474 	drm_modeset_lock(&dev->mode_config.connection_mutex, NULL);
2475 	drm_connector_update_privacy_screen_properties(connector, true);
2476 	drm_modeset_unlock(&dev->mode_config.connection_mutex);
2477 
2478 	drm_sysfs_connector_status_event(connector,
2479 				connector->privacy_screen_sw_state_property);
2480 	drm_sysfs_connector_status_event(connector,
2481 				connector->privacy_screen_hw_state_property);
2482 
2483 	return NOTIFY_DONE;
2484 }
2485 
2486 /**
2487  * drm_connector_attach_privacy_screen_provider - attach a privacy-screen to
2488  *    the connector
2489  * @connector: connector to attach the privacy-screen to
2490  * @priv: drm_privacy_screen to attach
2491  *
2492  * Create and attach the standard privacy-screen properties and register
2493  * a generic notifier for generating sysfs-connector-status-events
2494  * on external changes to the privacy-screen status.
2495  * This function takes ownership of the passed in drm_privacy_screen and will
2496  * call drm_privacy_screen_put() on it when the connector is destroyed.
2497  */
2498 void drm_connector_attach_privacy_screen_provider(
2499 	struct drm_connector *connector, struct drm_privacy_screen *priv)
2500 {
2501 	connector->privacy_screen = priv;
2502 	connector->privacy_screen_notifier.notifier_call =
2503 		drm_connector_privacy_screen_notifier;
2504 
2505 	drm_connector_create_privacy_screen_properties(connector);
2506 	drm_connector_update_privacy_screen_properties(connector, true);
2507 	drm_connector_attach_privacy_screen_properties(connector);
2508 }
2509 EXPORT_SYMBOL(drm_connector_attach_privacy_screen_provider);
2510 
2511 /**
2512  * drm_connector_update_privacy_screen - update connector's privacy-screen sw-state
2513  * @connector_state: connector-state to update the privacy-screen for
2514  *
2515  * This function calls drm_privacy_screen_set_sw_state() on the connector's
2516  * privacy-screen.
2517  *
2518  * If the connector has no privacy-screen, then this is a no-op.
2519  */
2520 void drm_connector_update_privacy_screen(const struct drm_connector_state *connector_state)
2521 {
2522 	struct drm_connector *connector = connector_state->connector;
2523 	int ret;
2524 
2525 	if (!connector->privacy_screen)
2526 		return;
2527 
2528 	ret = drm_privacy_screen_set_sw_state(connector->privacy_screen,
2529 					      connector_state->privacy_screen_sw_state);
2530 	if (ret) {
2531 		drm_err(connector->dev, "Error updating privacy-screen sw_state\n");
2532 		return;
2533 	}
2534 
2535 	/* The hw_state property value may have changed, update it. */
2536 	drm_connector_update_privacy_screen_properties(connector, false);
2537 }
2538 EXPORT_SYMBOL(drm_connector_update_privacy_screen);
2539 
2540 int drm_connector_set_obj_prop(struct drm_mode_object *obj,
2541 				    struct drm_property *property,
2542 				    uint64_t value)
2543 {
2544 	int ret = -EINVAL;
2545 	struct drm_connector *connector = obj_to_connector(obj);
2546 
2547 	/* Do DPMS ourselves */
2548 	if (property == connector->dev->mode_config.dpms_property) {
2549 		ret = (*connector->funcs->dpms)(connector, (int)value);
2550 	} else if (connector->funcs->set_property)
2551 		ret = connector->funcs->set_property(connector, property, value);
2552 
2553 	if (!ret)
2554 		drm_object_property_set_value(&connector->base, property, value);
2555 	return ret;
2556 }
2557 
2558 int drm_connector_property_set_ioctl(struct drm_device *dev,
2559 				     void *data, struct drm_file *file_priv)
2560 {
2561 	struct drm_mode_connector_set_property *conn_set_prop = data;
2562 	struct drm_mode_obj_set_property obj_set_prop = {
2563 		.value = conn_set_prop->value,
2564 		.prop_id = conn_set_prop->prop_id,
2565 		.obj_id = conn_set_prop->connector_id,
2566 		.obj_type = DRM_MODE_OBJECT_CONNECTOR
2567 	};
2568 
2569 	/* It does all the locking and checking we need */
2570 	return drm_mode_obj_set_property_ioctl(dev, &obj_set_prop, file_priv);
2571 }
2572 
2573 static struct drm_encoder *drm_connector_get_encoder(struct drm_connector *connector)
2574 {
2575 	/* For atomic drivers only state objects are synchronously updated and
2576 	 * protected by modeset locks, so check those first.
2577 	 */
2578 	if (connector->state)
2579 		return connector->state->best_encoder;
2580 	return connector->encoder;
2581 }
2582 
2583 static bool
2584 drm_mode_expose_to_userspace(const struct drm_display_mode *mode,
2585 			     const struct list_head *modes,
2586 			     const struct drm_file *file_priv)
2587 {
2588 	/*
2589 	 * If user-space hasn't configured the driver to expose the stereo 3D
2590 	 * modes, don't expose them.
2591 	 */
2592 	if (!file_priv->stereo_allowed && drm_mode_is_stereo(mode))
2593 		return false;
2594 	/*
2595 	 * If user-space hasn't configured the driver to expose the modes
2596 	 * with aspect-ratio, don't expose them. However if such a mode
2597 	 * is unique, let it be exposed, but reset the aspect-ratio flags
2598 	 * while preparing the list of user-modes.
2599 	 */
2600 	if (!file_priv->aspect_ratio_allowed) {
2601 		const struct drm_display_mode *mode_itr;
2602 
2603 		list_for_each_entry(mode_itr, modes, head) {
2604 			if (mode_itr->expose_to_userspace &&
2605 			    drm_mode_match(mode_itr, mode,
2606 					   DRM_MODE_MATCH_TIMINGS |
2607 					   DRM_MODE_MATCH_CLOCK |
2608 					   DRM_MODE_MATCH_FLAGS |
2609 					   DRM_MODE_MATCH_3D_FLAGS))
2610 				return false;
2611 		}
2612 	}
2613 
2614 	return true;
2615 }
2616 
2617 int drm_mode_getconnector(struct drm_device *dev, void *data,
2618 			  struct drm_file *file_priv)
2619 {
2620 	struct drm_mode_get_connector *out_resp = data;
2621 	struct drm_connector *connector;
2622 	struct drm_encoder *encoder;
2623 	struct drm_display_mode *mode;
2624 	int mode_count = 0;
2625 	int encoders_count = 0;
2626 	int ret = 0;
2627 	int copied = 0;
2628 	struct drm_mode_modeinfo u_mode;
2629 	struct drm_mode_modeinfo __user *mode_ptr;
2630 	uint32_t __user *encoder_ptr;
2631 	bool is_current_master;
2632 
2633 	if (!drm_core_check_feature(dev, DRIVER_MODESET))
2634 		return -EOPNOTSUPP;
2635 
2636 	memset(&u_mode, 0, sizeof(struct drm_mode_modeinfo));
2637 
2638 	connector = drm_connector_lookup(dev, file_priv, out_resp->connector_id);
2639 	if (!connector)
2640 		return -ENOENT;
2641 
2642 	encoders_count = hweight32(connector->possible_encoders);
2643 
2644 	if ((out_resp->count_encoders >= encoders_count) && encoders_count) {
2645 		copied = 0;
2646 		encoder_ptr = (uint32_t __user *)(unsigned long)(out_resp->encoders_ptr);
2647 
2648 		drm_connector_for_each_possible_encoder(connector, encoder) {
2649 			if (put_user(encoder->base.id, encoder_ptr + copied)) {
2650 				ret = -EFAULT;
2651 				goto out;
2652 			}
2653 			copied++;
2654 		}
2655 	}
2656 	out_resp->count_encoders = encoders_count;
2657 
2658 	out_resp->connector_id = connector->base.id;
2659 	out_resp->connector_type = connector->connector_type;
2660 	out_resp->connector_type_id = connector->connector_type_id;
2661 
2662 	is_current_master = drm_is_current_master(file_priv);
2663 
2664 	mutex_lock(&dev->mode_config.mutex);
2665 	if (out_resp->count_modes == 0) {
2666 		if (is_current_master)
2667 			connector->funcs->fill_modes(connector,
2668 						     dev->mode_config.max_width,
2669 						     dev->mode_config.max_height);
2670 		else
2671 			drm_dbg_kms(dev, "User-space requested a forced probe on [CONNECTOR:%d:%s] but is not the DRM master, demoting to read-only probe",
2672 				    connector->base.id, connector->name);
2673 	}
2674 
2675 	out_resp->mm_width = connector->display_info.width_mm;
2676 	out_resp->mm_height = connector->display_info.height_mm;
2677 	out_resp->subpixel = connector->display_info.subpixel_order;
2678 	out_resp->connection = connector->status;
2679 
2680 	/* delayed so we get modes regardless of pre-fill_modes state */
2681 	list_for_each_entry(mode, &connector->modes, head) {
2682 		WARN_ON(mode->expose_to_userspace);
2683 
2684 		if (drm_mode_expose_to_userspace(mode, &connector->modes,
2685 						 file_priv)) {
2686 			mode->expose_to_userspace = true;
2687 			mode_count++;
2688 		}
2689 	}
2690 
2691 	/*
2692 	 * This ioctl is called twice, once to determine how much space is
2693 	 * needed, and the 2nd time to fill it.
2694 	 */
2695 	if ((out_resp->count_modes >= mode_count) && mode_count) {
2696 		copied = 0;
2697 		mode_ptr = (struct drm_mode_modeinfo __user *)(unsigned long)out_resp->modes_ptr;
2698 		list_for_each_entry(mode, &connector->modes, head) {
2699 			if (!mode->expose_to_userspace)
2700 				continue;
2701 
2702 			/* Clear the tag for the next time around */
2703 			mode->expose_to_userspace = false;
2704 
2705 			drm_mode_convert_to_umode(&u_mode, mode);
2706 			/*
2707 			 * Reset aspect ratio flags of user-mode, if modes with
2708 			 * aspect-ratio are not supported.
2709 			 */
2710 			if (!file_priv->aspect_ratio_allowed)
2711 				u_mode.flags &= ~DRM_MODE_FLAG_PIC_AR_MASK;
2712 			if (copy_to_user(mode_ptr + copied,
2713 					 &u_mode, sizeof(u_mode))) {
2714 				ret = -EFAULT;
2715 
2716 				/*
2717 				 * Clear the tag for the rest of
2718 				 * the modes for the next time around.
2719 				 */
2720 				list_for_each_entry_continue(mode, &connector->modes, head)
2721 					mode->expose_to_userspace = false;
2722 
2723 				mutex_unlock(&dev->mode_config.mutex);
2724 
2725 				goto out;
2726 			}
2727 			copied++;
2728 		}
2729 	} else {
2730 		/* Clear the tag for the next time around */
2731 		list_for_each_entry(mode, &connector->modes, head)
2732 			mode->expose_to_userspace = false;
2733 	}
2734 
2735 	out_resp->count_modes = mode_count;
2736 	mutex_unlock(&dev->mode_config.mutex);
2737 
2738 	drm_modeset_lock(&dev->mode_config.connection_mutex, NULL);
2739 	encoder = drm_connector_get_encoder(connector);
2740 	if (encoder)
2741 		out_resp->encoder_id = encoder->base.id;
2742 	else
2743 		out_resp->encoder_id = 0;
2744 
2745 	/* Only grab properties after probing, to make sure EDID and other
2746 	 * properties reflect the latest status.
2747 	 */
2748 	ret = drm_mode_object_get_properties(&connector->base, file_priv->atomic,
2749 			(uint32_t __user *)(unsigned long)(out_resp->props_ptr),
2750 			(uint64_t __user *)(unsigned long)(out_resp->prop_values_ptr),
2751 			&out_resp->count_props);
2752 	drm_modeset_unlock(&dev->mode_config.connection_mutex);
2753 
2754 out:
2755 	drm_connector_put(connector);
2756 
2757 	return ret;
2758 }
2759 
2760 /**
2761  * drm_connector_find_by_fwnode - Find a connector based on the associated fwnode
2762  * @fwnode: fwnode for which to find the matching drm_connector
2763  *
2764  * This functions looks up a drm_connector based on its associated fwnode. When
2765  * a connector is found a reference to the connector is returned. The caller must
2766  * call drm_connector_put() to release this reference when it is done with the
2767  * connector.
2768  *
2769  * Returns: A reference to the found connector or an ERR_PTR().
2770  */
2771 struct drm_connector *drm_connector_find_by_fwnode(struct fwnode_handle *fwnode)
2772 {
2773 	struct drm_connector *connector, *found = ERR_PTR(-ENODEV);
2774 
2775 	if (!fwnode)
2776 		return ERR_PTR(-ENODEV);
2777 
2778 	mutex_lock(&connector_list_lock);
2779 
2780 	list_for_each_entry(connector, &connector_list, global_connector_list_entry) {
2781 		if (connector->fwnode == fwnode ||
2782 		    (connector->fwnode && connector->fwnode->secondary == fwnode)) {
2783 			drm_connector_get(connector);
2784 			found = connector;
2785 			break;
2786 		}
2787 	}
2788 
2789 	mutex_unlock(&connector_list_lock);
2790 
2791 	return found;
2792 }
2793 
2794 /**
2795  * drm_connector_oob_hotplug_event - Report out-of-band hotplug event to connector
2796  * @connector_fwnode: fwnode_handle to report the event on
2797  *
2798  * On some hardware a hotplug event notification may come from outside the display
2799  * driver / device. An example of this is some USB Type-C setups where the hardware
2800  * muxes the DisplayPort data and aux-lines but does not pass the altmode HPD
2801  * status bit to the GPU's DP HPD pin.
2802  *
2803  * This function can be used to report these out-of-band events after obtaining
2804  * a drm_connector reference through calling drm_connector_find_by_fwnode().
2805  */
2806 void drm_connector_oob_hotplug_event(struct fwnode_handle *connector_fwnode)
2807 {
2808 	struct drm_connector *connector;
2809 
2810 	connector = drm_connector_find_by_fwnode(connector_fwnode);
2811 	if (IS_ERR(connector))
2812 		return;
2813 
2814 	if (connector->funcs->oob_hotplug_event)
2815 		connector->funcs->oob_hotplug_event(connector);
2816 
2817 	drm_connector_put(connector);
2818 }
2819 EXPORT_SYMBOL(drm_connector_oob_hotplug_event);
2820 
2821 
2822 /**
2823  * DOC: Tile group
2824  *
2825  * Tile groups are used to represent tiled monitors with a unique integer
2826  * identifier. Tiled monitors using DisplayID v1.3 have a unique 8-byte handle,
2827  * we store this in a tile group, so we have a common identifier for all tiles
2828  * in a monitor group. The property is called "TILE". Drivers can manage tile
2829  * groups using drm_mode_create_tile_group(), drm_mode_put_tile_group() and
2830  * drm_mode_get_tile_group(). But this is only needed for internal panels where
2831  * the tile group information is exposed through a non-standard way.
2832  */
2833 
2834 static void drm_tile_group_free(struct kref *kref)
2835 {
2836 	struct drm_tile_group *tg = container_of(kref, struct drm_tile_group, refcount);
2837 	struct drm_device *dev = tg->dev;
2838 
2839 	mutex_lock(&dev->mode_config.idr_mutex);
2840 	idr_remove(&dev->mode_config.tile_idr, tg->id);
2841 	mutex_unlock(&dev->mode_config.idr_mutex);
2842 	kfree(tg);
2843 }
2844 
2845 /**
2846  * drm_mode_put_tile_group - drop a reference to a tile group.
2847  * @dev: DRM device
2848  * @tg: tile group to drop reference to.
2849  *
2850  * drop reference to tile group and free if 0.
2851  */
2852 void drm_mode_put_tile_group(struct drm_device *dev,
2853 			     struct drm_tile_group *tg)
2854 {
2855 	kref_put(&tg->refcount, drm_tile_group_free);
2856 }
2857 EXPORT_SYMBOL(drm_mode_put_tile_group);
2858 
2859 /**
2860  * drm_mode_get_tile_group - get a reference to an existing tile group
2861  * @dev: DRM device
2862  * @topology: 8-bytes unique per monitor.
2863  *
2864  * Use the unique bytes to get a reference to an existing tile group.
2865  *
2866  * RETURNS:
2867  * tile group or NULL if not found.
2868  */
2869 struct drm_tile_group *drm_mode_get_tile_group(struct drm_device *dev,
2870 					       const char topology[8])
2871 {
2872 	struct drm_tile_group *tg;
2873 	int id;
2874 
2875 	mutex_lock(&dev->mode_config.idr_mutex);
2876 	idr_for_each_entry(&dev->mode_config.tile_idr, tg, id) {
2877 		if (!memcmp(tg->group_data, topology, 8)) {
2878 			if (!kref_get_unless_zero(&tg->refcount))
2879 				tg = NULL;
2880 			mutex_unlock(&dev->mode_config.idr_mutex);
2881 			return tg;
2882 		}
2883 	}
2884 	mutex_unlock(&dev->mode_config.idr_mutex);
2885 	return NULL;
2886 }
2887 EXPORT_SYMBOL(drm_mode_get_tile_group);
2888 
2889 /**
2890  * drm_mode_create_tile_group - create a tile group from a displayid description
2891  * @dev: DRM device
2892  * @topology: 8-bytes unique per monitor.
2893  *
2894  * Create a tile group for the unique monitor, and get a unique
2895  * identifier for the tile group.
2896  *
2897  * RETURNS:
2898  * new tile group or NULL.
2899  */
2900 struct drm_tile_group *drm_mode_create_tile_group(struct drm_device *dev,
2901 						  const char topology[8])
2902 {
2903 	struct drm_tile_group *tg;
2904 	int ret;
2905 
2906 	tg = kzalloc(sizeof(*tg), GFP_KERNEL);
2907 	if (!tg)
2908 		return NULL;
2909 
2910 	kref_init(&tg->refcount);
2911 	memcpy(tg->group_data, topology, 8);
2912 	tg->dev = dev;
2913 
2914 	mutex_lock(&dev->mode_config.idr_mutex);
2915 	ret = idr_alloc(&dev->mode_config.tile_idr, tg, 1, 0, GFP_KERNEL);
2916 	if (ret >= 0) {
2917 		tg->id = ret;
2918 	} else {
2919 		kfree(tg);
2920 		tg = NULL;
2921 	}
2922 
2923 	mutex_unlock(&dev->mode_config.idr_mutex);
2924 	return tg;
2925 }
2926 EXPORT_SYMBOL(drm_mode_create_tile_group);
2927