xref: /openbmc/linux/drivers/acpi/acpi_video.c (revision 0e4cac55)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *  video.c - ACPI Video Driver
4  *
5  *  Copyright (C) 2004 Luming Yu <luming.yu@intel.com>
6  *  Copyright (C) 2004 Bruno Ducrot <ducrot@poupinou.org>
7  *  Copyright (C) 2006 Thomas Tuttle <linux-kernel@ttuttle.net>
8  */
9 
10 #define pr_fmt(fmt) "ACPI: video: " fmt
11 
12 #include <linux/kernel.h>
13 #include <linux/module.h>
14 #include <linux/init.h>
15 #include <linux/types.h>
16 #include <linux/list.h>
17 #include <linux/mutex.h>
18 #include <linux/input.h>
19 #include <linux/backlight.h>
20 #include <linux/thermal.h>
21 #include <linux/sort.h>
22 #include <linux/pci.h>
23 #include <linux/pci_ids.h>
24 #include <linux/slab.h>
25 #include <linux/dmi.h>
26 #include <linux/suspend.h>
27 #include <linux/acpi.h>
28 #include <acpi/video.h>
29 #include <linux/uaccess.h>
30 
31 #define ACPI_VIDEO_BUS_NAME		"Video Bus"
32 #define ACPI_VIDEO_DEVICE_NAME		"Video Device"
33 
34 #define MAX_NAME_LEN	20
35 
36 MODULE_AUTHOR("Bruno Ducrot");
37 MODULE_DESCRIPTION("ACPI Video Driver");
38 MODULE_LICENSE("GPL");
39 
40 static bool brightness_switch_enabled = true;
41 module_param(brightness_switch_enabled, bool, 0644);
42 
43 /*
44  * By default, we don't allow duplicate ACPI video bus devices
45  * under the same VGA controller
46  */
47 static bool allow_duplicates;
48 module_param(allow_duplicates, bool, 0644);
49 
50 #define REPORT_OUTPUT_KEY_EVENTS		0x01
51 #define REPORT_BRIGHTNESS_KEY_EVENTS		0x02
52 static int report_key_events = -1;
53 module_param(report_key_events, int, 0644);
54 MODULE_PARM_DESC(report_key_events,
55 	"0: none, 1: output changes, 2: brightness changes, 3: all");
56 
57 static int hw_changes_brightness = -1;
58 module_param(hw_changes_brightness, int, 0644);
59 MODULE_PARM_DESC(hw_changes_brightness,
60 	"Set this to 1 on buggy hw which changes the brightness itself when "
61 	"a hotkey is pressed: -1: auto, 0: normal 1: hw-changes-brightness");
62 
63 /*
64  * Whether the struct acpi_video_device_attrib::device_id_scheme bit should be
65  * assumed even if not actually set.
66  */
67 static bool device_id_scheme = false;
68 module_param(device_id_scheme, bool, 0444);
69 
70 static int only_lcd = -1;
71 module_param(only_lcd, int, 0444);
72 
73 static bool may_report_brightness_keys;
74 static int register_count;
75 static DEFINE_MUTEX(register_count_mutex);
76 static DEFINE_MUTEX(video_list_lock);
77 static LIST_HEAD(video_bus_head);
78 static int acpi_video_bus_add(struct acpi_device *device);
79 static void acpi_video_bus_remove(struct acpi_device *device);
80 static void acpi_video_bus_notify(acpi_handle handle, u32 event, void *data);
81 
82 /*
83  * Indices in the _BCL method response: the first two items are special,
84  * the rest are all supported levels.
85  *
86  * See page 575 of the ACPI spec 3.0
87  */
88 enum acpi_video_level_idx {
89 	ACPI_VIDEO_AC_LEVEL,		/* level when machine has full power */
90 	ACPI_VIDEO_BATTERY_LEVEL,	/* level when machine is on batteries */
91 	ACPI_VIDEO_FIRST_LEVEL,		/* actual supported levels begin here */
92 };
93 
94 static const struct acpi_device_id video_device_ids[] = {
95 	{ACPI_VIDEO_HID, 0},
96 	{"", 0},
97 };
98 MODULE_DEVICE_TABLE(acpi, video_device_ids);
99 
100 static struct acpi_driver acpi_video_bus = {
101 	.name = "video",
102 	.class = ACPI_VIDEO_CLASS,
103 	.ids = video_device_ids,
104 	.ops = {
105 		.add = acpi_video_bus_add,
106 		.remove = acpi_video_bus_remove,
107 		},
108 };
109 
110 struct acpi_video_bus_flags {
111 	u8 multihead:1;		/* can switch video heads */
112 	u8 rom:1;		/* can retrieve a video rom */
113 	u8 post:1;		/* can configure the head to */
114 	u8 reserved:5;
115 };
116 
117 struct acpi_video_bus_cap {
118 	u8 _DOS:1;		/* Enable/Disable output switching */
119 	u8 _DOD:1;		/* Enumerate all devices attached to display adapter */
120 	u8 _ROM:1;		/* Get ROM Data */
121 	u8 _GPD:1;		/* Get POST Device */
122 	u8 _SPD:1;		/* Set POST Device */
123 	u8 _VPO:1;		/* Video POST Options */
124 	u8 reserved:2;
125 };
126 
127 struct acpi_video_device_attrib {
128 	u32 display_index:4;	/* A zero-based instance of the Display */
129 	u32 display_port_attachment:4;	/* This field differentiates the display type */
130 	u32 display_type:4;	/* Describe the specific type in use */
131 	u32 vendor_specific:4;	/* Chipset Vendor Specific */
132 	u32 bios_can_detect:1;	/* BIOS can detect the device */
133 	u32 depend_on_vga:1;	/* Non-VGA output device whose power is related to
134 				   the VGA device. */
135 	u32 pipe_id:3;		/* For VGA multiple-head devices. */
136 	u32 reserved:10;	/* Must be 0 */
137 
138 	/*
139 	 * The device ID might not actually follow the scheme described by this
140 	 * struct acpi_video_device_attrib. If it does, then this bit
141 	 * device_id_scheme is set; otherwise, other fields should be ignored.
142 	 *
143 	 * (but also see the global flag device_id_scheme)
144 	 */
145 	u32 device_id_scheme:1;
146 };
147 
148 struct acpi_video_enumerated_device {
149 	union {
150 		u32 int_val;
151 		struct acpi_video_device_attrib attrib;
152 	} value;
153 	struct acpi_video_device *bind_info;
154 };
155 
156 struct acpi_video_bus {
157 	struct acpi_device *device;
158 	bool backlight_registered;
159 	u8 dos_setting;
160 	struct acpi_video_enumerated_device *attached_array;
161 	u8 attached_count;
162 	u8 child_count;
163 	struct acpi_video_bus_cap cap;
164 	struct acpi_video_bus_flags flags;
165 	struct list_head video_device_list;
166 	struct mutex device_list_lock;	/* protects video_device_list */
167 	struct list_head entry;
168 	struct input_dev *input;
169 	char phys[32];	/* for input device */
170 	struct notifier_block pm_nb;
171 };
172 
173 struct acpi_video_device_flags {
174 	u8 crt:1;
175 	u8 lcd:1;
176 	u8 tvout:1;
177 	u8 dvi:1;
178 	u8 bios:1;
179 	u8 unknown:1;
180 	u8 notify:1;
181 	u8 reserved:1;
182 };
183 
184 struct acpi_video_device_cap {
185 	u8 _ADR:1;		/* Return the unique ID */
186 	u8 _BCL:1;		/* Query list of brightness control levels supported */
187 	u8 _BCM:1;		/* Set the brightness level */
188 	u8 _BQC:1;		/* Get current brightness level */
189 	u8 _BCQ:1;		/* Some buggy BIOS uses _BCQ instead of _BQC */
190 	u8 _DDC:1;		/* Return the EDID for this device */
191 };
192 
193 struct acpi_video_device {
194 	unsigned long device_id;
195 	struct acpi_video_device_flags flags;
196 	struct acpi_video_device_cap cap;
197 	struct list_head entry;
198 	struct delayed_work switch_brightness_work;
199 	int switch_brightness_event;
200 	struct acpi_video_bus *video;
201 	struct acpi_device *dev;
202 	struct acpi_video_device_brightness *brightness;
203 	struct backlight_device *backlight;
204 	struct thermal_cooling_device *cooling_dev;
205 };
206 
207 static void acpi_video_device_notify(acpi_handle handle, u32 event, void *data);
208 static void acpi_video_device_rebind(struct acpi_video_bus *video);
209 static void acpi_video_device_bind(struct acpi_video_bus *video,
210 				   struct acpi_video_device *device);
211 static int acpi_video_device_enumerate(struct acpi_video_bus *video);
212 static int acpi_video_device_lcd_set_level(struct acpi_video_device *device,
213 			int level);
214 static int acpi_video_device_lcd_get_level_current(
215 			struct acpi_video_device *device,
216 			unsigned long long *level, bool raw);
217 static int acpi_video_get_next_level(struct acpi_video_device *device,
218 				     u32 level_current, u32 event);
219 static void acpi_video_switch_brightness(struct work_struct *work);
220 
221 /* backlight device sysfs support */
222 static int acpi_video_get_brightness(struct backlight_device *bd)
223 {
224 	unsigned long long cur_level;
225 	int i;
226 	struct acpi_video_device *vd = bl_get_data(bd);
227 
228 	if (acpi_video_device_lcd_get_level_current(vd, &cur_level, false))
229 		return -EINVAL;
230 	for (i = ACPI_VIDEO_FIRST_LEVEL; i < vd->brightness->count; i++) {
231 		if (vd->brightness->levels[i] == cur_level)
232 			return i - ACPI_VIDEO_FIRST_LEVEL;
233 	}
234 	return 0;
235 }
236 
237 static int acpi_video_set_brightness(struct backlight_device *bd)
238 {
239 	int request_level = bd->props.brightness + ACPI_VIDEO_FIRST_LEVEL;
240 	struct acpi_video_device *vd = bl_get_data(bd);
241 
242 	cancel_delayed_work(&vd->switch_brightness_work);
243 	return acpi_video_device_lcd_set_level(vd,
244 				vd->brightness->levels[request_level]);
245 }
246 
247 static const struct backlight_ops acpi_backlight_ops = {
248 	.get_brightness = acpi_video_get_brightness,
249 	.update_status  = acpi_video_set_brightness,
250 };
251 
252 /* thermal cooling device callbacks */
253 static int video_get_max_state(struct thermal_cooling_device *cooling_dev,
254 			       unsigned long *state)
255 {
256 	struct acpi_device *device = cooling_dev->devdata;
257 	struct acpi_video_device *video = acpi_driver_data(device);
258 
259 	*state = video->brightness->count - ACPI_VIDEO_FIRST_LEVEL - 1;
260 	return 0;
261 }
262 
263 static int video_get_cur_state(struct thermal_cooling_device *cooling_dev,
264 			       unsigned long *state)
265 {
266 	struct acpi_device *device = cooling_dev->devdata;
267 	struct acpi_video_device *video = acpi_driver_data(device);
268 	unsigned long long level;
269 	int offset;
270 
271 	if (acpi_video_device_lcd_get_level_current(video, &level, false))
272 		return -EINVAL;
273 	for (offset = ACPI_VIDEO_FIRST_LEVEL; offset < video->brightness->count;
274 	     offset++)
275 		if (level == video->brightness->levels[offset]) {
276 			*state = video->brightness->count - offset - 1;
277 			return 0;
278 		}
279 
280 	return -EINVAL;
281 }
282 
283 static int
284 video_set_cur_state(struct thermal_cooling_device *cooling_dev, unsigned long state)
285 {
286 	struct acpi_device *device = cooling_dev->devdata;
287 	struct acpi_video_device *video = acpi_driver_data(device);
288 	int level;
289 
290 	if (state >= video->brightness->count - ACPI_VIDEO_FIRST_LEVEL)
291 		return -EINVAL;
292 
293 	state = video->brightness->count - state;
294 	level = video->brightness->levels[state - 1];
295 	return acpi_video_device_lcd_set_level(video, level);
296 }
297 
298 static const struct thermal_cooling_device_ops video_cooling_ops = {
299 	.get_max_state = video_get_max_state,
300 	.get_cur_state = video_get_cur_state,
301 	.set_cur_state = video_set_cur_state,
302 };
303 
304 /*
305  * --------------------------------------------------------------------------
306  *                             Video Management
307  * --------------------------------------------------------------------------
308  */
309 
310 static int
311 acpi_video_device_lcd_query_levels(acpi_handle handle,
312 				   union acpi_object **levels)
313 {
314 	int status;
315 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
316 	union acpi_object *obj;
317 
318 
319 	*levels = NULL;
320 
321 	status = acpi_evaluate_object(handle, "_BCL", NULL, &buffer);
322 	if (ACPI_FAILURE(status))
323 		return status;
324 	obj = (union acpi_object *)buffer.pointer;
325 	if (!obj || (obj->type != ACPI_TYPE_PACKAGE)) {
326 		acpi_handle_info(handle, "Invalid _BCL data\n");
327 		status = -EFAULT;
328 		goto err;
329 	}
330 
331 	*levels = obj;
332 
333 	return 0;
334 
335 err:
336 	kfree(buffer.pointer);
337 
338 	return status;
339 }
340 
341 static int
342 acpi_video_device_lcd_set_level(struct acpi_video_device *device, int level)
343 {
344 	int status;
345 	int state;
346 
347 	status = acpi_execute_simple_method(device->dev->handle,
348 					    "_BCM", level);
349 	if (ACPI_FAILURE(status)) {
350 		acpi_handle_info(device->dev->handle, "_BCM evaluation failed\n");
351 		return -EIO;
352 	}
353 
354 	device->brightness->curr = level;
355 	for (state = ACPI_VIDEO_FIRST_LEVEL; state < device->brightness->count;
356 	     state++)
357 		if (level == device->brightness->levels[state]) {
358 			if (device->backlight)
359 				device->backlight->props.brightness =
360 					state - ACPI_VIDEO_FIRST_LEVEL;
361 			return 0;
362 		}
363 
364 	acpi_handle_info(device->dev->handle, "Current brightness invalid\n");
365 	return -EINVAL;
366 }
367 
368 /*
369  * For some buggy _BQC methods, we need to add a constant value to
370  * the _BQC return value to get the actual current brightness level
371  */
372 
373 static int bqc_offset_aml_bug_workaround;
374 static int video_set_bqc_offset(const struct dmi_system_id *d)
375 {
376 	bqc_offset_aml_bug_workaround = 9;
377 	return 0;
378 }
379 
380 static int video_set_device_id_scheme(const struct dmi_system_id *d)
381 {
382 	device_id_scheme = true;
383 	return 0;
384 }
385 
386 static int video_enable_only_lcd(const struct dmi_system_id *d)
387 {
388 	only_lcd = true;
389 	return 0;
390 }
391 
392 static int video_set_report_key_events(const struct dmi_system_id *id)
393 {
394 	if (report_key_events == -1)
395 		report_key_events = (uintptr_t)id->driver_data;
396 	return 0;
397 }
398 
399 static int video_hw_changes_brightness(
400 	const struct dmi_system_id *d)
401 {
402 	if (hw_changes_brightness == -1)
403 		hw_changes_brightness = 1;
404 	return 0;
405 }
406 
407 static const struct dmi_system_id video_dmi_table[] = {
408 	/*
409 	 * Broken _BQC workaround http://bugzilla.kernel.org/show_bug.cgi?id=13121
410 	 */
411 	{
412 	 .callback = video_set_bqc_offset,
413 	 .ident = "Acer Aspire 5720",
414 	 .matches = {
415 		DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
416 		DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5720"),
417 		},
418 	},
419 	{
420 	 .callback = video_set_bqc_offset,
421 	 .ident = "Acer Aspire 5710Z",
422 	 .matches = {
423 		DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
424 		DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5710Z"),
425 		},
426 	},
427 	{
428 	 .callback = video_set_bqc_offset,
429 	 .ident = "eMachines E510",
430 	 .matches = {
431 		DMI_MATCH(DMI_BOARD_VENDOR, "EMACHINES"),
432 		DMI_MATCH(DMI_PRODUCT_NAME, "eMachines E510"),
433 		},
434 	},
435 	{
436 	 .callback = video_set_bqc_offset,
437 	 .ident = "Acer Aspire 5315",
438 	 .matches = {
439 		DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
440 		DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5315"),
441 		},
442 	},
443 	{
444 	 .callback = video_set_bqc_offset,
445 	 .ident = "Acer Aspire 7720",
446 	 .matches = {
447 		DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
448 		DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 7720"),
449 		},
450 	},
451 
452 	/*
453 	 * Some machine's _DOD IDs don't have bit 31(Device ID Scheme) set
454 	 * but the IDs actually follow the Device ID Scheme.
455 	 */
456 	{
457 	 /* https://bugzilla.kernel.org/show_bug.cgi?id=104121 */
458 	 .callback = video_set_device_id_scheme,
459 	 .ident = "ESPRIMO Mobile M9410",
460 	 .matches = {
461 		DMI_MATCH(DMI_SYS_VENDOR, "FUJITSU SIEMENS"),
462 		DMI_MATCH(DMI_PRODUCT_NAME, "ESPRIMO Mobile M9410"),
463 		},
464 	},
465 	/*
466 	 * Some machines have multiple video output devices, but only the one
467 	 * that is the type of LCD can do the backlight control so we should not
468 	 * register backlight interface for other video output devices.
469 	 */
470 	{
471 	 /* https://bugzilla.kernel.org/show_bug.cgi?id=104121 */
472 	 .callback = video_enable_only_lcd,
473 	 .ident = "ESPRIMO Mobile M9410",
474 	 .matches = {
475 		DMI_MATCH(DMI_SYS_VENDOR, "FUJITSU SIEMENS"),
476 		DMI_MATCH(DMI_PRODUCT_NAME, "ESPRIMO Mobile M9410"),
477 		},
478 	},
479 	/*
480 	 * Some machines report wrong key events on the acpi-bus, suppress
481 	 * key event reporting on these.  Note this is only intended to work
482 	 * around events which are plain wrong. In some cases we get double
483 	 * events, in this case acpi-video is considered the canonical source
484 	 * and the events from the other source should be filtered. E.g.
485 	 * by calling acpi_video_handles_brightness_key_presses() from the
486 	 * vendor acpi/wmi driver or by using /lib/udev/hwdb.d/60-keyboard.hwdb
487 	 */
488 	{
489 	 .callback = video_set_report_key_events,
490 	 .driver_data = (void *)((uintptr_t)REPORT_OUTPUT_KEY_EVENTS),
491 	 .ident = "Dell Vostro V131",
492 	 .matches = {
493 		DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
494 		DMI_MATCH(DMI_PRODUCT_NAME, "Vostro V131"),
495 		},
496 	},
497 	{
498 	 .callback = video_set_report_key_events,
499 	 .driver_data = (void *)((uintptr_t)REPORT_BRIGHTNESS_KEY_EVENTS),
500 	 .ident = "Dell Vostro 3350",
501 	 .matches = {
502 		DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
503 		DMI_MATCH(DMI_PRODUCT_NAME, "Vostro 3350"),
504 		},
505 	},
506 	/*
507 	 * Some machines change the brightness themselves when a brightness
508 	 * hotkey gets pressed, despite us telling them not to. In this case
509 	 * acpi_video_device_notify() should only call backlight_force_update(
510 	 * BACKLIGHT_UPDATE_HOTKEY) and not do anything else.
511 	 */
512 	{
513 	 /* https://bugzilla.kernel.org/show_bug.cgi?id=204077 */
514 	 .callback = video_hw_changes_brightness,
515 	 .ident = "Packard Bell EasyNote MZ35",
516 	 .matches = {
517 		DMI_MATCH(DMI_SYS_VENDOR, "Packard Bell"),
518 		DMI_MATCH(DMI_PRODUCT_NAME, "EasyNote MZ35"),
519 		},
520 	},
521 	{}
522 };
523 
524 static unsigned long long
525 acpi_video_bqc_value_to_level(struct acpi_video_device *device,
526 			      unsigned long long bqc_value)
527 {
528 	unsigned long long level;
529 
530 	if (device->brightness->flags._BQC_use_index) {
531 		/*
532 		 * _BQC returns an index that doesn't account for the first 2
533 		 * items with special meaning (see enum acpi_video_level_idx),
534 		 * so we need to compensate for that by offsetting ourselves
535 		 */
536 		if (device->brightness->flags._BCL_reversed)
537 			bqc_value = device->brightness->count -
538 				ACPI_VIDEO_FIRST_LEVEL - 1 - bqc_value;
539 
540 		level = device->brightness->levels[bqc_value +
541 						   ACPI_VIDEO_FIRST_LEVEL];
542 	} else {
543 		level = bqc_value;
544 	}
545 
546 	level += bqc_offset_aml_bug_workaround;
547 
548 	return level;
549 }
550 
551 static int
552 acpi_video_device_lcd_get_level_current(struct acpi_video_device *device,
553 					unsigned long long *level, bool raw)
554 {
555 	acpi_status status = AE_OK;
556 	int i;
557 
558 	if (device->cap._BQC || device->cap._BCQ) {
559 		char *buf = device->cap._BQC ? "_BQC" : "_BCQ";
560 
561 		status = acpi_evaluate_integer(device->dev->handle, buf,
562 						NULL, level);
563 		if (ACPI_SUCCESS(status)) {
564 			if (raw) {
565 				/*
566 				 * Caller has indicated he wants the raw
567 				 * value returned by _BQC, so don't furtherly
568 				 * mess with the value.
569 				 */
570 				return 0;
571 			}
572 
573 			*level = acpi_video_bqc_value_to_level(device, *level);
574 
575 			for (i = ACPI_VIDEO_FIRST_LEVEL;
576 			     i < device->brightness->count; i++)
577 				if (device->brightness->levels[i] == *level) {
578 					device->brightness->curr = *level;
579 					return 0;
580 				}
581 			/*
582 			 * BQC returned an invalid level.
583 			 * Stop using it.
584 			 */
585 			acpi_handle_info(device->dev->handle,
586 					 "%s returned an invalid level", buf);
587 			device->cap._BQC = device->cap._BCQ = 0;
588 		} else {
589 			/*
590 			 * Fixme:
591 			 * should we return an error or ignore this failure?
592 			 * dev->brightness->curr is a cached value which stores
593 			 * the correct current backlight level in most cases.
594 			 * ACPI video backlight still works w/ buggy _BQC.
595 			 * http://bugzilla.kernel.org/show_bug.cgi?id=12233
596 			 */
597 			acpi_handle_info(device->dev->handle,
598 					 "%s evaluation failed", buf);
599 			device->cap._BQC = device->cap._BCQ = 0;
600 		}
601 	}
602 
603 	*level = device->brightness->curr;
604 	return 0;
605 }
606 
607 static int
608 acpi_video_device_EDID(struct acpi_video_device *device,
609 		       union acpi_object **edid, ssize_t length)
610 {
611 	int status;
612 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
613 	union acpi_object *obj;
614 	union acpi_object arg0 = { ACPI_TYPE_INTEGER };
615 	struct acpi_object_list args = { 1, &arg0 };
616 
617 
618 	*edid = NULL;
619 
620 	if (!device)
621 		return -ENODEV;
622 	if (length == 128)
623 		arg0.integer.value = 1;
624 	else if (length == 256)
625 		arg0.integer.value = 2;
626 	else
627 		return -EINVAL;
628 
629 	status = acpi_evaluate_object(device->dev->handle, "_DDC", &args, &buffer);
630 	if (ACPI_FAILURE(status))
631 		return -ENODEV;
632 
633 	obj = buffer.pointer;
634 
635 	if (obj && obj->type == ACPI_TYPE_BUFFER)
636 		*edid = obj;
637 	else {
638 		acpi_handle_info(device->dev->handle, "Invalid _DDC data\n");
639 		status = -EFAULT;
640 		kfree(obj);
641 	}
642 
643 	return status;
644 }
645 
646 /* bus */
647 
648 /*
649  *  Arg:
650  *	video		: video bus device pointer
651  *	bios_flag	:
652  *		0.	The system BIOS should NOT automatically switch(toggle)
653  *			the active display output.
654  *		1.	The system BIOS should automatically switch (toggle) the
655  *			active display output. No switch event.
656  *		2.	The _DGS value should be locked.
657  *		3.	The system BIOS should not automatically switch (toggle) the
658  *			active display output, but instead generate the display switch
659  *			event notify code.
660  *	lcd_flag	:
661  *		0.	The system BIOS should automatically control the brightness level
662  *			of the LCD when:
663  *			- the power changes from AC to DC (ACPI appendix B)
664  *			- a brightness hotkey gets pressed (implied by Win7/8 backlight docs)
665  *		1.	The system BIOS should NOT automatically control the brightness
666  *			level of the LCD when:
667  *			- the power changes from AC to DC (ACPI appendix B)
668  *			- a brightness hotkey gets pressed (implied by Win7/8 backlight docs)
669  *  Return Value:
670  *		-EINVAL	wrong arg.
671  */
672 
673 static int
674 acpi_video_bus_DOS(struct acpi_video_bus *video, int bios_flag, int lcd_flag)
675 {
676 	acpi_status status;
677 
678 	if (!video->cap._DOS)
679 		return 0;
680 
681 	if (bios_flag < 0 || bios_flag > 3 || lcd_flag < 0 || lcd_flag > 1)
682 		return -EINVAL;
683 	video->dos_setting = (lcd_flag << 2) | bios_flag;
684 	status = acpi_execute_simple_method(video->device->handle, "_DOS",
685 					    (lcd_flag << 2) | bios_flag);
686 	if (ACPI_FAILURE(status))
687 		return -EIO;
688 
689 	return 0;
690 }
691 
692 /*
693  * Simple comparison function used to sort backlight levels.
694  */
695 
696 static int
697 acpi_video_cmp_level(const void *a, const void *b)
698 {
699 	return *(int *)a - *(int *)b;
700 }
701 
702 /*
703  * Decides if _BQC/_BCQ for this system is usable
704  *
705  * We do this by changing the level first and then read out the current
706  * brightness level, if the value does not match, find out if it is using
707  * index. If not, clear the _BQC/_BCQ capability.
708  */
709 static int acpi_video_bqc_quirk(struct acpi_video_device *device,
710 				int max_level, int current_level)
711 {
712 	struct acpi_video_device_brightness *br = device->brightness;
713 	int result;
714 	unsigned long long level;
715 	int test_level;
716 
717 	/* don't mess with existing known broken systems */
718 	if (bqc_offset_aml_bug_workaround)
719 		return 0;
720 
721 	/*
722 	 * Some systems always report current brightness level as maximum
723 	 * through _BQC, we need to test another value for them. However,
724 	 * there is a subtlety:
725 	 *
726 	 * If the _BCL package ordering is descending, the first level
727 	 * (br->levels[2]) is likely to be 0, and if the number of levels
728 	 * matches the number of steps, we might confuse a returned level to
729 	 * mean the index.
730 	 *
731 	 * For example:
732 	 *
733 	 *     current_level = max_level = 100
734 	 *     test_level = 0
735 	 *     returned level = 100
736 	 *
737 	 * In this case 100 means the level, not the index, and _BCM failed.
738 	 * Still, if the _BCL package ordering is descending, the index of
739 	 * level 0 is also 100, so we assume _BQC is indexed, when it's not.
740 	 *
741 	 * This causes all _BQC calls to return bogus values causing weird
742 	 * behavior from the user's perspective.  For example:
743 	 *
744 	 * xbacklight -set 10; xbacklight -set 20;
745 	 *
746 	 * would flash to 90% and then slowly down to the desired level (20).
747 	 *
748 	 * The solution is simple; test anything other than the first level
749 	 * (e.g. 1).
750 	 */
751 	test_level = current_level == max_level
752 		? br->levels[ACPI_VIDEO_FIRST_LEVEL + 1]
753 		: max_level;
754 
755 	result = acpi_video_device_lcd_set_level(device, test_level);
756 	if (result)
757 		return result;
758 
759 	result = acpi_video_device_lcd_get_level_current(device, &level, true);
760 	if (result)
761 		return result;
762 
763 	if (level != test_level) {
764 		/* buggy _BQC found, need to find out if it uses index */
765 		if (level < br->count) {
766 			if (br->flags._BCL_reversed)
767 				level = br->count - ACPI_VIDEO_FIRST_LEVEL - 1 - level;
768 			if (br->levels[level + ACPI_VIDEO_FIRST_LEVEL] == test_level)
769 				br->flags._BQC_use_index = 1;
770 		}
771 
772 		if (!br->flags._BQC_use_index)
773 			device->cap._BQC = device->cap._BCQ = 0;
774 	}
775 
776 	return 0;
777 }
778 
779 int acpi_video_get_levels(struct acpi_device *device,
780 			  struct acpi_video_device_brightness **dev_br,
781 			  int *pmax_level)
782 {
783 	union acpi_object *obj = NULL;
784 	int i, max_level = 0, count = 0, level_ac_battery = 0;
785 	union acpi_object *o;
786 	struct acpi_video_device_brightness *br = NULL;
787 	int result = 0;
788 	u32 value;
789 
790 	if (ACPI_FAILURE(acpi_video_device_lcd_query_levels(device->handle, &obj))) {
791 		acpi_handle_debug(device->handle,
792 				  "Could not query available LCD brightness level\n");
793 		result = -ENODEV;
794 		goto out;
795 	}
796 
797 	if (obj->package.count < ACPI_VIDEO_FIRST_LEVEL) {
798 		result = -EINVAL;
799 		goto out;
800 	}
801 
802 	br = kzalloc(sizeof(*br), GFP_KERNEL);
803 	if (!br) {
804 		result = -ENOMEM;
805 		goto out;
806 	}
807 
808 	/*
809 	 * Note that we have to reserve 2 extra items (ACPI_VIDEO_FIRST_LEVEL),
810 	 * in order to account for buggy BIOS which don't export the first two
811 	 * special levels (see below)
812 	 */
813 	br->levels = kmalloc_array(obj->package.count + ACPI_VIDEO_FIRST_LEVEL,
814 				   sizeof(*br->levels),
815 				   GFP_KERNEL);
816 	if (!br->levels) {
817 		result = -ENOMEM;
818 		goto out_free;
819 	}
820 
821 	for (i = 0; i < obj->package.count; i++) {
822 		o = (union acpi_object *)&obj->package.elements[i];
823 		if (o->type != ACPI_TYPE_INTEGER) {
824 			acpi_handle_info(device->handle, "Invalid data\n");
825 			continue;
826 		}
827 		value = (u32) o->integer.value;
828 		/* Skip duplicate entries */
829 		if (count > ACPI_VIDEO_FIRST_LEVEL
830 		    && br->levels[count - 1] == value)
831 			continue;
832 
833 		br->levels[count] = value;
834 
835 		if (br->levels[count] > max_level)
836 			max_level = br->levels[count];
837 		count++;
838 	}
839 
840 	/*
841 	 * some buggy BIOS don't export the levels
842 	 * when machine is on AC/Battery in _BCL package.
843 	 * In this case, the first two elements in _BCL packages
844 	 * are also supported brightness levels that OS should take care of.
845 	 */
846 	for (i = ACPI_VIDEO_FIRST_LEVEL; i < count; i++) {
847 		if (br->levels[i] == br->levels[ACPI_VIDEO_AC_LEVEL])
848 			level_ac_battery++;
849 		if (br->levels[i] == br->levels[ACPI_VIDEO_BATTERY_LEVEL])
850 			level_ac_battery++;
851 	}
852 
853 	if (level_ac_battery < ACPI_VIDEO_FIRST_LEVEL) {
854 		level_ac_battery = ACPI_VIDEO_FIRST_LEVEL - level_ac_battery;
855 		br->flags._BCL_no_ac_battery_levels = 1;
856 		for (i = (count - 1 + level_ac_battery);
857 		     i >= ACPI_VIDEO_FIRST_LEVEL; i--)
858 			br->levels[i] = br->levels[i - level_ac_battery];
859 		count += level_ac_battery;
860 	} else if (level_ac_battery > ACPI_VIDEO_FIRST_LEVEL)
861 		acpi_handle_info(device->handle,
862 				 "Too many duplicates in _BCL package");
863 
864 	/* Check if the _BCL package is in a reversed order */
865 	if (max_level == br->levels[ACPI_VIDEO_FIRST_LEVEL]) {
866 		br->flags._BCL_reversed = 1;
867 		sort(&br->levels[ACPI_VIDEO_FIRST_LEVEL],
868 		     count - ACPI_VIDEO_FIRST_LEVEL,
869 		     sizeof(br->levels[ACPI_VIDEO_FIRST_LEVEL]),
870 		     acpi_video_cmp_level, NULL);
871 	} else if (max_level != br->levels[count - 1])
872 		acpi_handle_info(device->handle,
873 				 "Found unordered _BCL package");
874 
875 	br->count = count;
876 	*dev_br = br;
877 	if (pmax_level)
878 		*pmax_level = max_level;
879 
880 out:
881 	kfree(obj);
882 	return result;
883 out_free:
884 	kfree(br);
885 	goto out;
886 }
887 EXPORT_SYMBOL(acpi_video_get_levels);
888 
889 /*
890  *  Arg:
891  *	device	: video output device (LCD, CRT, ..)
892  *
893  *  Return Value:
894  *	Maximum brightness level
895  *
896  *  Allocate and initialize device->brightness.
897  */
898 
899 static int
900 acpi_video_init_brightness(struct acpi_video_device *device)
901 {
902 	int i, max_level = 0;
903 	unsigned long long level, level_old;
904 	struct acpi_video_device_brightness *br = NULL;
905 	int result;
906 
907 	result = acpi_video_get_levels(device->dev, &br, &max_level);
908 	if (result)
909 		return result;
910 	device->brightness = br;
911 
912 	/* _BQC uses INDEX while _BCL uses VALUE in some laptops */
913 	br->curr = level = max_level;
914 
915 	if (!device->cap._BQC)
916 		goto set_level;
917 
918 	result = acpi_video_device_lcd_get_level_current(device,
919 							 &level_old, true);
920 	if (result)
921 		goto out_free_levels;
922 
923 	result = acpi_video_bqc_quirk(device, max_level, level_old);
924 	if (result)
925 		goto out_free_levels;
926 	/*
927 	 * cap._BQC may get cleared due to _BQC is found to be broken
928 	 * in acpi_video_bqc_quirk, so check again here.
929 	 */
930 	if (!device->cap._BQC)
931 		goto set_level;
932 
933 	level = acpi_video_bqc_value_to_level(device, level_old);
934 	/*
935 	 * On some buggy laptops, _BQC returns an uninitialized
936 	 * value when invoked for the first time, i.e.
937 	 * level_old is invalid (no matter whether it's a level
938 	 * or an index). Set the backlight to max_level in this case.
939 	 */
940 	for (i = ACPI_VIDEO_FIRST_LEVEL; i < br->count; i++)
941 		if (level == br->levels[i])
942 			break;
943 	if (i == br->count || !level)
944 		level = max_level;
945 
946 set_level:
947 	result = acpi_video_device_lcd_set_level(device, level);
948 	if (result)
949 		goto out_free_levels;
950 
951 	acpi_handle_debug(device->dev->handle, "found %d brightness levels\n",
952 			  br->count - ACPI_VIDEO_FIRST_LEVEL);
953 
954 	return 0;
955 
956 out_free_levels:
957 	kfree(br->levels);
958 	kfree(br);
959 	device->brightness = NULL;
960 	return result;
961 }
962 
963 /*
964  *  Arg:
965  *	device	: video output device (LCD, CRT, ..)
966  *
967  *  Return Value:
968  *	None
969  *
970  *  Find out all required AML methods defined under the output
971  *  device.
972  */
973 
974 static void acpi_video_device_find_cap(struct acpi_video_device *device)
975 {
976 	if (acpi_has_method(device->dev->handle, "_ADR"))
977 		device->cap._ADR = 1;
978 	if (acpi_has_method(device->dev->handle, "_BCL"))
979 		device->cap._BCL = 1;
980 	if (acpi_has_method(device->dev->handle, "_BCM"))
981 		device->cap._BCM = 1;
982 	if (acpi_has_method(device->dev->handle, "_BQC")) {
983 		device->cap._BQC = 1;
984 	} else if (acpi_has_method(device->dev->handle, "_BCQ")) {
985 		acpi_handle_info(device->dev->handle,
986 				 "_BCQ is used instead of _BQC\n");
987 		device->cap._BCQ = 1;
988 	}
989 
990 	if (acpi_has_method(device->dev->handle, "_DDC"))
991 		device->cap._DDC = 1;
992 }
993 
994 /*
995  *  Arg:
996  *	device	: video output device (VGA)
997  *
998  *  Return Value:
999  *	None
1000  *
1001  *  Find out all required AML methods defined under the video bus device.
1002  */
1003 
1004 static void acpi_video_bus_find_cap(struct acpi_video_bus *video)
1005 {
1006 	if (acpi_has_method(video->device->handle, "_DOS"))
1007 		video->cap._DOS = 1;
1008 	if (acpi_has_method(video->device->handle, "_DOD"))
1009 		video->cap._DOD = 1;
1010 	if (acpi_has_method(video->device->handle, "_ROM"))
1011 		video->cap._ROM = 1;
1012 	if (acpi_has_method(video->device->handle, "_GPD"))
1013 		video->cap._GPD = 1;
1014 	if (acpi_has_method(video->device->handle, "_SPD"))
1015 		video->cap._SPD = 1;
1016 	if (acpi_has_method(video->device->handle, "_VPO"))
1017 		video->cap._VPO = 1;
1018 }
1019 
1020 /*
1021  * Check whether the video bus device has required AML method to
1022  * support the desired features
1023  */
1024 
1025 static int acpi_video_bus_check(struct acpi_video_bus *video)
1026 {
1027 	acpi_status status = -ENOENT;
1028 	struct pci_dev *dev;
1029 
1030 	if (!video)
1031 		return -EINVAL;
1032 
1033 	dev = acpi_get_pci_dev(video->device->handle);
1034 	if (!dev)
1035 		return -ENODEV;
1036 	pci_dev_put(dev);
1037 
1038 	/*
1039 	 * Since there is no HID, CID and so on for VGA driver, we have
1040 	 * to check well known required nodes.
1041 	 */
1042 
1043 	/* Does this device support video switching? */
1044 	if (video->cap._DOS || video->cap._DOD) {
1045 		if (!video->cap._DOS) {
1046 			pr_info(FW_BUG "ACPI(%s) defines _DOD but not _DOS\n",
1047 				acpi_device_bid(video->device));
1048 		}
1049 		video->flags.multihead = 1;
1050 		status = 0;
1051 	}
1052 
1053 	/* Does this device support retrieving a video ROM? */
1054 	if (video->cap._ROM) {
1055 		video->flags.rom = 1;
1056 		status = 0;
1057 	}
1058 
1059 	/* Does this device support configuring which video device to POST? */
1060 	if (video->cap._GPD && video->cap._SPD && video->cap._VPO) {
1061 		video->flags.post = 1;
1062 		status = 0;
1063 	}
1064 
1065 	return status;
1066 }
1067 
1068 /*
1069  * --------------------------------------------------------------------------
1070  *                               Driver Interface
1071  * --------------------------------------------------------------------------
1072  */
1073 
1074 /* device interface */
1075 static struct acpi_video_device_attrib *
1076 acpi_video_get_device_attr(struct acpi_video_bus *video, unsigned long device_id)
1077 {
1078 	struct acpi_video_enumerated_device *ids;
1079 	int i;
1080 
1081 	for (i = 0; i < video->attached_count; i++) {
1082 		ids = &video->attached_array[i];
1083 		if ((ids->value.int_val & 0xffff) == device_id)
1084 			return &ids->value.attrib;
1085 	}
1086 
1087 	return NULL;
1088 }
1089 
1090 static int
1091 acpi_video_get_device_type(struct acpi_video_bus *video,
1092 			   unsigned long device_id)
1093 {
1094 	struct acpi_video_enumerated_device *ids;
1095 	int i;
1096 
1097 	for (i = 0; i < video->attached_count; i++) {
1098 		ids = &video->attached_array[i];
1099 		if ((ids->value.int_val & 0xffff) == device_id)
1100 			return ids->value.int_val;
1101 	}
1102 
1103 	return 0;
1104 }
1105 
1106 static int acpi_video_bus_get_one_device(struct acpi_device *device, void *arg)
1107 {
1108 	struct acpi_video_bus *video = arg;
1109 	struct acpi_video_device_attrib *attribute;
1110 	struct acpi_video_device *data;
1111 	unsigned long long device_id;
1112 	acpi_status status;
1113 	int device_type;
1114 
1115 	status = acpi_evaluate_integer(device->handle, "_ADR", NULL, &device_id);
1116 	/* Skip devices without _ADR instead of failing. */
1117 	if (ACPI_FAILURE(status))
1118 		goto exit;
1119 
1120 	data = kzalloc(sizeof(struct acpi_video_device), GFP_KERNEL);
1121 	if (!data) {
1122 		dev_dbg(&device->dev, "Cannot attach\n");
1123 		return -ENOMEM;
1124 	}
1125 
1126 	strcpy(acpi_device_name(device), ACPI_VIDEO_DEVICE_NAME);
1127 	strcpy(acpi_device_class(device), ACPI_VIDEO_CLASS);
1128 	device->driver_data = data;
1129 
1130 	data->device_id = device_id;
1131 	data->video = video;
1132 	data->dev = device;
1133 	INIT_DELAYED_WORK(&data->switch_brightness_work,
1134 			  acpi_video_switch_brightness);
1135 
1136 	attribute = acpi_video_get_device_attr(video, device_id);
1137 
1138 	if (attribute && (attribute->device_id_scheme || device_id_scheme)) {
1139 		switch (attribute->display_type) {
1140 		case ACPI_VIDEO_DISPLAY_CRT:
1141 			data->flags.crt = 1;
1142 			break;
1143 		case ACPI_VIDEO_DISPLAY_TV:
1144 			data->flags.tvout = 1;
1145 			break;
1146 		case ACPI_VIDEO_DISPLAY_DVI:
1147 			data->flags.dvi = 1;
1148 			break;
1149 		case ACPI_VIDEO_DISPLAY_LCD:
1150 			data->flags.lcd = 1;
1151 			break;
1152 		default:
1153 			data->flags.unknown = 1;
1154 			break;
1155 		}
1156 		if (attribute->bios_can_detect)
1157 			data->flags.bios = 1;
1158 	} else {
1159 		/* Check for legacy IDs */
1160 		device_type = acpi_video_get_device_type(video, device_id);
1161 		/* Ignore bits 16 and 18-20 */
1162 		switch (device_type & 0xffe2ffff) {
1163 		case ACPI_VIDEO_DISPLAY_LEGACY_MONITOR:
1164 			data->flags.crt = 1;
1165 			break;
1166 		case ACPI_VIDEO_DISPLAY_LEGACY_PANEL:
1167 			data->flags.lcd = 1;
1168 			break;
1169 		case ACPI_VIDEO_DISPLAY_LEGACY_TV:
1170 			data->flags.tvout = 1;
1171 			break;
1172 		default:
1173 			data->flags.unknown = 1;
1174 		}
1175 	}
1176 
1177 	acpi_video_device_bind(video, data);
1178 	acpi_video_device_find_cap(data);
1179 
1180 	if (data->cap._BCM && data->cap._BCL)
1181 		may_report_brightness_keys = true;
1182 
1183 	mutex_lock(&video->device_list_lock);
1184 	list_add_tail(&data->entry, &video->video_device_list);
1185 	mutex_unlock(&video->device_list_lock);
1186 
1187 exit:
1188 	video->child_count++;
1189 	return 0;
1190 }
1191 
1192 /*
1193  *  Arg:
1194  *	video	: video bus device
1195  *
1196  *  Return:
1197  *	none
1198  *
1199  *  Enumerate the video device list of the video bus,
1200  *  bind the ids with the corresponding video devices
1201  *  under the video bus.
1202  */
1203 
1204 static void acpi_video_device_rebind(struct acpi_video_bus *video)
1205 {
1206 	struct acpi_video_device *dev;
1207 
1208 	mutex_lock(&video->device_list_lock);
1209 
1210 	list_for_each_entry(dev, &video->video_device_list, entry)
1211 		acpi_video_device_bind(video, dev);
1212 
1213 	mutex_unlock(&video->device_list_lock);
1214 }
1215 
1216 /*
1217  *  Arg:
1218  *	video	: video bus device
1219  *	device	: video output device under the video
1220  *		bus
1221  *
1222  *  Return:
1223  *	none
1224  *
1225  *  Bind the ids with the corresponding video devices
1226  *  under the video bus.
1227  */
1228 
1229 static void
1230 acpi_video_device_bind(struct acpi_video_bus *video,
1231 		       struct acpi_video_device *device)
1232 {
1233 	struct acpi_video_enumerated_device *ids;
1234 	int i;
1235 
1236 	for (i = 0; i < video->attached_count; i++) {
1237 		ids = &video->attached_array[i];
1238 		if (device->device_id == (ids->value.int_val & 0xffff)) {
1239 			ids->bind_info = device;
1240 			acpi_handle_debug(video->device->handle, "%s: %d\n",
1241 					  __func__, i);
1242 		}
1243 	}
1244 }
1245 
1246 static bool acpi_video_device_in_dod(struct acpi_video_device *device)
1247 {
1248 	struct acpi_video_bus *video = device->video;
1249 	int i;
1250 
1251 	/*
1252 	 * If we have a broken _DOD or we have more than 8 output devices
1253 	 * under the graphics controller node that we can't proper deal with
1254 	 * in the operation region code currently, no need to test.
1255 	 */
1256 	if (!video->attached_count || video->child_count > 8)
1257 		return true;
1258 
1259 	for (i = 0; i < video->attached_count; i++) {
1260 		if ((video->attached_array[i].value.int_val & 0xfff) ==
1261 		    (device->device_id & 0xfff))
1262 			return true;
1263 	}
1264 
1265 	return false;
1266 }
1267 
1268 /*
1269  *  Arg:
1270  *	video	: video bus device
1271  *
1272  *  Return:
1273  *	< 0	: error
1274  *
1275  *  Call _DOD to enumerate all devices attached to display adapter
1276  *
1277  */
1278 
1279 static int acpi_video_device_enumerate(struct acpi_video_bus *video)
1280 {
1281 	int status;
1282 	int count;
1283 	int i;
1284 	struct acpi_video_enumerated_device *active_list;
1285 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
1286 	union acpi_object *dod = NULL;
1287 	union acpi_object *obj;
1288 
1289 	if (!video->cap._DOD)
1290 		return AE_NOT_EXIST;
1291 
1292 	status = acpi_evaluate_object(video->device->handle, "_DOD", NULL, &buffer);
1293 	if (ACPI_FAILURE(status)) {
1294 		acpi_handle_info(video->device->handle,
1295 				 "_DOD evaluation failed: %s\n",
1296 				 acpi_format_exception(status));
1297 		return status;
1298 	}
1299 
1300 	dod = buffer.pointer;
1301 	if (!dod || (dod->type != ACPI_TYPE_PACKAGE)) {
1302 		acpi_handle_info(video->device->handle, "Invalid _DOD data\n");
1303 		status = -EFAULT;
1304 		goto out;
1305 	}
1306 
1307 	acpi_handle_debug(video->device->handle, "Found %d video heads in _DOD\n",
1308 			  dod->package.count);
1309 
1310 	active_list = kcalloc(1 + dod->package.count,
1311 			      sizeof(struct acpi_video_enumerated_device),
1312 			      GFP_KERNEL);
1313 	if (!active_list) {
1314 		status = -ENOMEM;
1315 		goto out;
1316 	}
1317 
1318 	count = 0;
1319 	for (i = 0; i < dod->package.count; i++) {
1320 		obj = &dod->package.elements[i];
1321 
1322 		if (obj->type != ACPI_TYPE_INTEGER) {
1323 			acpi_handle_info(video->device->handle,
1324 					 "Invalid _DOD data in element %d\n", i);
1325 			continue;
1326 		}
1327 
1328 		active_list[count].value.int_val = obj->integer.value;
1329 		active_list[count].bind_info = NULL;
1330 
1331 		acpi_handle_debug(video->device->handle,
1332 				  "_DOD element[%d] = %d\n", i,
1333 				  (int)obj->integer.value);
1334 
1335 		count++;
1336 	}
1337 
1338 	kfree(video->attached_array);
1339 
1340 	video->attached_array = active_list;
1341 	video->attached_count = count;
1342 
1343 out:
1344 	kfree(buffer.pointer);
1345 	return status;
1346 }
1347 
1348 static int
1349 acpi_video_get_next_level(struct acpi_video_device *device,
1350 			  u32 level_current, u32 event)
1351 {
1352 	int min, max, min_above, max_below, i, l, delta = 255;
1353 	max = max_below = 0;
1354 	min = min_above = 255;
1355 	/* Find closest level to level_current */
1356 	for (i = ACPI_VIDEO_FIRST_LEVEL; i < device->brightness->count; i++) {
1357 		l = device->brightness->levels[i];
1358 		if (abs(l - level_current) < abs(delta)) {
1359 			delta = l - level_current;
1360 			if (!delta)
1361 				break;
1362 		}
1363 	}
1364 	/* Adjust level_current to closest available level */
1365 	level_current += delta;
1366 	for (i = ACPI_VIDEO_FIRST_LEVEL; i < device->brightness->count; i++) {
1367 		l = device->brightness->levels[i];
1368 		if (l < min)
1369 			min = l;
1370 		if (l > max)
1371 			max = l;
1372 		if (l < min_above && l > level_current)
1373 			min_above = l;
1374 		if (l > max_below && l < level_current)
1375 			max_below = l;
1376 	}
1377 
1378 	switch (event) {
1379 	case ACPI_VIDEO_NOTIFY_CYCLE_BRIGHTNESS:
1380 		return (level_current < max) ? min_above : min;
1381 	case ACPI_VIDEO_NOTIFY_INC_BRIGHTNESS:
1382 		return (level_current < max) ? min_above : max;
1383 	case ACPI_VIDEO_NOTIFY_DEC_BRIGHTNESS:
1384 		return (level_current > min) ? max_below : min;
1385 	case ACPI_VIDEO_NOTIFY_ZERO_BRIGHTNESS:
1386 	case ACPI_VIDEO_NOTIFY_DISPLAY_OFF:
1387 		return 0;
1388 	default:
1389 		return level_current;
1390 	}
1391 }
1392 
1393 static void
1394 acpi_video_switch_brightness(struct work_struct *work)
1395 {
1396 	struct acpi_video_device *device = container_of(to_delayed_work(work),
1397 			     struct acpi_video_device, switch_brightness_work);
1398 	unsigned long long level_current, level_next;
1399 	int event = device->switch_brightness_event;
1400 	int result = -EINVAL;
1401 
1402 	/* no warning message if acpi_backlight=vendor or a quirk is used */
1403 	if (!device->backlight)
1404 		return;
1405 
1406 	if (!device->brightness)
1407 		goto out;
1408 
1409 	result = acpi_video_device_lcd_get_level_current(device,
1410 							 &level_current,
1411 							 false);
1412 	if (result)
1413 		goto out;
1414 
1415 	level_next = acpi_video_get_next_level(device, level_current, event);
1416 
1417 	result = acpi_video_device_lcd_set_level(device, level_next);
1418 
1419 	if (!result)
1420 		backlight_force_update(device->backlight,
1421 				       BACKLIGHT_UPDATE_HOTKEY);
1422 
1423 out:
1424 	if (result)
1425 		acpi_handle_info(device->dev->handle,
1426 				 "Failed to switch brightness\n");
1427 }
1428 
1429 int acpi_video_get_edid(struct acpi_device *device, int type, int device_id,
1430 			void **edid)
1431 {
1432 	struct acpi_video_bus *video;
1433 	struct acpi_video_device *video_device;
1434 	union acpi_object *buffer = NULL;
1435 	acpi_status status;
1436 	int i, length;
1437 
1438 	if (!device || !acpi_driver_data(device))
1439 		return -EINVAL;
1440 
1441 	video = acpi_driver_data(device);
1442 
1443 	for (i = 0; i < video->attached_count; i++) {
1444 		video_device = video->attached_array[i].bind_info;
1445 		length = 256;
1446 
1447 		if (!video_device)
1448 			continue;
1449 
1450 		if (!video_device->cap._DDC)
1451 			continue;
1452 
1453 		if (type) {
1454 			switch (type) {
1455 			case ACPI_VIDEO_DISPLAY_CRT:
1456 				if (!video_device->flags.crt)
1457 					continue;
1458 				break;
1459 			case ACPI_VIDEO_DISPLAY_TV:
1460 				if (!video_device->flags.tvout)
1461 					continue;
1462 				break;
1463 			case ACPI_VIDEO_DISPLAY_DVI:
1464 				if (!video_device->flags.dvi)
1465 					continue;
1466 				break;
1467 			case ACPI_VIDEO_DISPLAY_LCD:
1468 				if (!video_device->flags.lcd)
1469 					continue;
1470 				break;
1471 			}
1472 		} else if (video_device->device_id != device_id) {
1473 			continue;
1474 		}
1475 
1476 		status = acpi_video_device_EDID(video_device, &buffer, length);
1477 
1478 		if (ACPI_FAILURE(status) || !buffer ||
1479 		    buffer->type != ACPI_TYPE_BUFFER) {
1480 			length = 128;
1481 			status = acpi_video_device_EDID(video_device, &buffer,
1482 							length);
1483 			if (ACPI_FAILURE(status) || !buffer ||
1484 			    buffer->type != ACPI_TYPE_BUFFER) {
1485 				continue;
1486 			}
1487 		}
1488 
1489 		*edid = buffer->buffer.pointer;
1490 		return length;
1491 	}
1492 
1493 	return -ENODEV;
1494 }
1495 EXPORT_SYMBOL(acpi_video_get_edid);
1496 
1497 static int
1498 acpi_video_bus_get_devices(struct acpi_video_bus *video,
1499 			   struct acpi_device *device)
1500 {
1501 	/*
1502 	 * There are systems where video module known to work fine regardless
1503 	 * of broken _DOD and ignoring returned value here doesn't cause
1504 	 * any issues later.
1505 	 */
1506 	acpi_video_device_enumerate(video);
1507 
1508 	return acpi_dev_for_each_child(device, acpi_video_bus_get_one_device, video);
1509 }
1510 
1511 /* acpi_video interface */
1512 
1513 /*
1514  * Win8 requires setting bit2 of _DOS to let firmware know it shouldn't
1515  * perform any automatic brightness change on receiving a notification.
1516  */
1517 static int acpi_video_bus_start_devices(struct acpi_video_bus *video)
1518 {
1519 	return acpi_video_bus_DOS(video, 0,
1520 				  acpi_osi_is_win8() ? 1 : 0);
1521 }
1522 
1523 static int acpi_video_bus_stop_devices(struct acpi_video_bus *video)
1524 {
1525 	return acpi_video_bus_DOS(video, 0,
1526 				  acpi_osi_is_win8() ? 0 : 1);
1527 }
1528 
1529 static void acpi_video_bus_notify(acpi_handle handle, u32 event, void *data)
1530 {
1531 	struct acpi_device *device = data;
1532 	struct acpi_video_bus *video = acpi_driver_data(device);
1533 	struct input_dev *input;
1534 	int keycode = 0;
1535 
1536 	if (!video || !video->input)
1537 		return;
1538 
1539 	input = video->input;
1540 
1541 	switch (event) {
1542 	case ACPI_VIDEO_NOTIFY_SWITCH:	/* User requested a switch,
1543 					 * most likely via hotkey. */
1544 		keycode = KEY_SWITCHVIDEOMODE;
1545 		break;
1546 
1547 	case ACPI_VIDEO_NOTIFY_PROBE:	/* User plugged in or removed a video
1548 					 * connector. */
1549 		acpi_video_device_enumerate(video);
1550 		acpi_video_device_rebind(video);
1551 		keycode = KEY_SWITCHVIDEOMODE;
1552 		break;
1553 
1554 	case ACPI_VIDEO_NOTIFY_CYCLE:	/* Cycle Display output hotkey pressed. */
1555 		keycode = KEY_SWITCHVIDEOMODE;
1556 		break;
1557 	case ACPI_VIDEO_NOTIFY_NEXT_OUTPUT:	/* Next Display output hotkey pressed. */
1558 		keycode = KEY_VIDEO_NEXT;
1559 		break;
1560 	case ACPI_VIDEO_NOTIFY_PREV_OUTPUT:	/* previous Display output hotkey pressed. */
1561 		keycode = KEY_VIDEO_PREV;
1562 		break;
1563 
1564 	default:
1565 		acpi_handle_debug(device->handle, "Unsupported event [0x%x]\n",
1566 				  event);
1567 		break;
1568 	}
1569 
1570 	if (acpi_notifier_call_chain(device, event, 0))
1571 		/* Something vetoed the keypress. */
1572 		keycode = 0;
1573 
1574 	if (keycode && (report_key_events & REPORT_OUTPUT_KEY_EVENTS)) {
1575 		input_report_key(input, keycode, 1);
1576 		input_sync(input);
1577 		input_report_key(input, keycode, 0);
1578 		input_sync(input);
1579 	}
1580 }
1581 
1582 static void brightness_switch_event(struct acpi_video_device *video_device,
1583 				    u32 event)
1584 {
1585 	if (!brightness_switch_enabled)
1586 		return;
1587 
1588 	video_device->switch_brightness_event = event;
1589 	schedule_delayed_work(&video_device->switch_brightness_work, HZ / 10);
1590 }
1591 
1592 static void acpi_video_device_notify(acpi_handle handle, u32 event, void *data)
1593 {
1594 	struct acpi_video_device *video_device = data;
1595 	struct acpi_device *device = NULL;
1596 	struct acpi_video_bus *bus;
1597 	struct input_dev *input;
1598 	int keycode = 0;
1599 
1600 	if (!video_device)
1601 		return;
1602 
1603 	device = video_device->dev;
1604 	bus = video_device->video;
1605 	input = bus->input;
1606 
1607 	if (hw_changes_brightness > 0) {
1608 		if (video_device->backlight)
1609 			backlight_force_update(video_device->backlight,
1610 					       BACKLIGHT_UPDATE_HOTKEY);
1611 		acpi_notifier_call_chain(device, event, 0);
1612 		return;
1613 	}
1614 
1615 	switch (event) {
1616 	case ACPI_VIDEO_NOTIFY_CYCLE_BRIGHTNESS:	/* Cycle brightness */
1617 		brightness_switch_event(video_device, event);
1618 		keycode = KEY_BRIGHTNESS_CYCLE;
1619 		break;
1620 	case ACPI_VIDEO_NOTIFY_INC_BRIGHTNESS:	/* Increase brightness */
1621 		brightness_switch_event(video_device, event);
1622 		keycode = KEY_BRIGHTNESSUP;
1623 		break;
1624 	case ACPI_VIDEO_NOTIFY_DEC_BRIGHTNESS:	/* Decrease brightness */
1625 		brightness_switch_event(video_device, event);
1626 		keycode = KEY_BRIGHTNESSDOWN;
1627 		break;
1628 	case ACPI_VIDEO_NOTIFY_ZERO_BRIGHTNESS:	/* zero brightness */
1629 		brightness_switch_event(video_device, event);
1630 		keycode = KEY_BRIGHTNESS_ZERO;
1631 		break;
1632 	case ACPI_VIDEO_NOTIFY_DISPLAY_OFF:	/* display device off */
1633 		brightness_switch_event(video_device, event);
1634 		keycode = KEY_DISPLAY_OFF;
1635 		break;
1636 	default:
1637 		acpi_handle_debug(handle, "Unsupported event [0x%x]\n", event);
1638 		break;
1639 	}
1640 
1641 	if (keycode)
1642 		may_report_brightness_keys = true;
1643 
1644 	acpi_notifier_call_chain(device, event, 0);
1645 
1646 	if (keycode && (report_key_events & REPORT_BRIGHTNESS_KEY_EVENTS)) {
1647 		input_report_key(input, keycode, 1);
1648 		input_sync(input);
1649 		input_report_key(input, keycode, 0);
1650 		input_sync(input);
1651 	}
1652 }
1653 
1654 static int acpi_video_resume(struct notifier_block *nb,
1655 				unsigned long val, void *ign)
1656 {
1657 	struct acpi_video_bus *video;
1658 	struct acpi_video_device *video_device;
1659 	int i;
1660 
1661 	switch (val) {
1662 	case PM_POST_HIBERNATION:
1663 	case PM_POST_SUSPEND:
1664 	case PM_POST_RESTORE:
1665 		video = container_of(nb, struct acpi_video_bus, pm_nb);
1666 
1667 		dev_info(&video->device->dev, "Restoring backlight state\n");
1668 
1669 		for (i = 0; i < video->attached_count; i++) {
1670 			video_device = video->attached_array[i].bind_info;
1671 			if (video_device && video_device->brightness)
1672 				acpi_video_device_lcd_set_level(video_device,
1673 						video_device->brightness->curr);
1674 		}
1675 
1676 		return NOTIFY_OK;
1677 	}
1678 	return NOTIFY_DONE;
1679 }
1680 
1681 static acpi_status
1682 acpi_video_bus_match(acpi_handle handle, u32 level, void *context,
1683 			void **return_value)
1684 {
1685 	struct acpi_device *device = context;
1686 	struct acpi_device *sibling;
1687 
1688 	if (handle == device->handle)
1689 		return AE_CTRL_TERMINATE;
1690 
1691 	sibling = acpi_fetch_acpi_dev(handle);
1692 	if (!sibling)
1693 		return AE_OK;
1694 
1695 	if (!strcmp(acpi_device_name(sibling), ACPI_VIDEO_BUS_NAME))
1696 			return AE_ALREADY_EXISTS;
1697 
1698 	return AE_OK;
1699 }
1700 
1701 static void acpi_video_dev_register_backlight(struct acpi_video_device *device)
1702 {
1703 	struct backlight_properties props;
1704 	struct pci_dev *pdev;
1705 	acpi_handle acpi_parent;
1706 	struct device *parent = NULL;
1707 	int result;
1708 	static int count;
1709 	char *name;
1710 
1711 	result = acpi_video_init_brightness(device);
1712 	if (result)
1713 		return;
1714 
1715 	name = kasprintf(GFP_KERNEL, "acpi_video%d", count);
1716 	if (!name)
1717 		return;
1718 	count++;
1719 
1720 	acpi_get_parent(device->dev->handle, &acpi_parent);
1721 
1722 	pdev = acpi_get_pci_dev(acpi_parent);
1723 	if (pdev) {
1724 		parent = &pdev->dev;
1725 		pci_dev_put(pdev);
1726 	}
1727 
1728 	memset(&props, 0, sizeof(struct backlight_properties));
1729 	props.type = BACKLIGHT_FIRMWARE;
1730 	props.max_brightness =
1731 		device->brightness->count - ACPI_VIDEO_FIRST_LEVEL - 1;
1732 	device->backlight = backlight_device_register(name,
1733 						      parent,
1734 						      device,
1735 						      &acpi_backlight_ops,
1736 						      &props);
1737 	kfree(name);
1738 	if (IS_ERR(device->backlight)) {
1739 		device->backlight = NULL;
1740 		return;
1741 	}
1742 
1743 	/*
1744 	 * Save current brightness level in case we have to restore it
1745 	 * before acpi_video_device_lcd_set_level() is called next time.
1746 	 */
1747 	device->backlight->props.brightness =
1748 			acpi_video_get_brightness(device->backlight);
1749 
1750 	device->cooling_dev = thermal_cooling_device_register("LCD",
1751 				device->dev, &video_cooling_ops);
1752 	if (IS_ERR(device->cooling_dev)) {
1753 		/*
1754 		 * Set cooling_dev to NULL so we don't crash trying to free it.
1755 		 * Also, why the hell we are returning early and not attempt to
1756 		 * register video output if cooling device registration failed?
1757 		 * -- dtor
1758 		 */
1759 		device->cooling_dev = NULL;
1760 		return;
1761 	}
1762 
1763 	dev_info(&device->dev->dev, "registered as cooling_device%d\n",
1764 		 device->cooling_dev->id);
1765 	result = sysfs_create_link(&device->dev->dev.kobj,
1766 			&device->cooling_dev->device.kobj,
1767 			"thermal_cooling");
1768 	if (result)
1769 		pr_info("sysfs link creation failed\n");
1770 
1771 	result = sysfs_create_link(&device->cooling_dev->device.kobj,
1772 			&device->dev->dev.kobj, "device");
1773 	if (result)
1774 		pr_info("Reverse sysfs link creation failed\n");
1775 }
1776 
1777 static void acpi_video_run_bcl_for_osi(struct acpi_video_bus *video)
1778 {
1779 	struct acpi_video_device *dev;
1780 	union acpi_object *levels;
1781 
1782 	mutex_lock(&video->device_list_lock);
1783 	list_for_each_entry(dev, &video->video_device_list, entry) {
1784 		if (!acpi_video_device_lcd_query_levels(dev->dev->handle, &levels))
1785 			kfree(levels);
1786 	}
1787 	mutex_unlock(&video->device_list_lock);
1788 }
1789 
1790 static bool acpi_video_should_register_backlight(struct acpi_video_device *dev)
1791 {
1792 	/*
1793 	 * Do not create backlight device for video output
1794 	 * device that is not in the enumerated list.
1795 	 */
1796 	if (!acpi_video_device_in_dod(dev)) {
1797 		dev_dbg(&dev->dev->dev, "not in _DOD list, ignore\n");
1798 		return false;
1799 	}
1800 
1801 	if (only_lcd)
1802 		return dev->flags.lcd;
1803 	return true;
1804 }
1805 
1806 static int acpi_video_bus_register_backlight(struct acpi_video_bus *video)
1807 {
1808 	struct acpi_video_device *dev;
1809 
1810 	if (video->backlight_registered)
1811 		return 0;
1812 
1813 	if (acpi_video_get_backlight_type() != acpi_backlight_video)
1814 		return 0;
1815 
1816 	mutex_lock(&video->device_list_lock);
1817 	list_for_each_entry(dev, &video->video_device_list, entry) {
1818 		if (acpi_video_should_register_backlight(dev))
1819 			acpi_video_dev_register_backlight(dev);
1820 	}
1821 	mutex_unlock(&video->device_list_lock);
1822 
1823 	video->backlight_registered = true;
1824 
1825 	video->pm_nb.notifier_call = acpi_video_resume;
1826 	video->pm_nb.priority = 0;
1827 	return register_pm_notifier(&video->pm_nb);
1828 }
1829 
1830 static void acpi_video_dev_unregister_backlight(struct acpi_video_device *device)
1831 {
1832 	if (device->backlight) {
1833 		backlight_device_unregister(device->backlight);
1834 		device->backlight = NULL;
1835 	}
1836 	if (device->brightness) {
1837 		kfree(device->brightness->levels);
1838 		kfree(device->brightness);
1839 		device->brightness = NULL;
1840 	}
1841 	if (device->cooling_dev) {
1842 		sysfs_remove_link(&device->dev->dev.kobj, "thermal_cooling");
1843 		sysfs_remove_link(&device->cooling_dev->device.kobj, "device");
1844 		thermal_cooling_device_unregister(device->cooling_dev);
1845 		device->cooling_dev = NULL;
1846 	}
1847 }
1848 
1849 static int acpi_video_bus_unregister_backlight(struct acpi_video_bus *video)
1850 {
1851 	struct acpi_video_device *dev;
1852 	int error;
1853 
1854 	if (!video->backlight_registered)
1855 		return 0;
1856 
1857 	error = unregister_pm_notifier(&video->pm_nb);
1858 
1859 	mutex_lock(&video->device_list_lock);
1860 	list_for_each_entry(dev, &video->video_device_list, entry)
1861 		acpi_video_dev_unregister_backlight(dev);
1862 	mutex_unlock(&video->device_list_lock);
1863 
1864 	video->backlight_registered = false;
1865 
1866 	return error;
1867 }
1868 
1869 static void acpi_video_dev_add_notify_handler(struct acpi_video_device *device)
1870 {
1871 	acpi_status status;
1872 	struct acpi_device *adev = device->dev;
1873 
1874 	status = acpi_install_notify_handler(adev->handle, ACPI_DEVICE_NOTIFY,
1875 					     acpi_video_device_notify, device);
1876 	if (ACPI_FAILURE(status))
1877 		dev_err(&adev->dev, "Error installing notify handler\n");
1878 	else
1879 		device->flags.notify = 1;
1880 }
1881 
1882 static int acpi_video_bus_add_notify_handler(struct acpi_video_bus *video)
1883 {
1884 	struct input_dev *input;
1885 	struct acpi_video_device *dev;
1886 	int error;
1887 
1888 	video->input = input = input_allocate_device();
1889 	if (!input) {
1890 		error = -ENOMEM;
1891 		goto out;
1892 	}
1893 
1894 	error = acpi_video_bus_start_devices(video);
1895 	if (error)
1896 		goto err_free_input;
1897 
1898 	snprintf(video->phys, sizeof(video->phys),
1899 			"%s/video/input0", acpi_device_hid(video->device));
1900 
1901 	input->name = acpi_device_name(video->device);
1902 	input->phys = video->phys;
1903 	input->id.bustype = BUS_HOST;
1904 	input->id.product = 0x06;
1905 	input->dev.parent = &video->device->dev;
1906 	input->evbit[0] = BIT(EV_KEY);
1907 	set_bit(KEY_SWITCHVIDEOMODE, input->keybit);
1908 	set_bit(KEY_VIDEO_NEXT, input->keybit);
1909 	set_bit(KEY_VIDEO_PREV, input->keybit);
1910 	set_bit(KEY_BRIGHTNESS_CYCLE, input->keybit);
1911 	set_bit(KEY_BRIGHTNESSUP, input->keybit);
1912 	set_bit(KEY_BRIGHTNESSDOWN, input->keybit);
1913 	set_bit(KEY_BRIGHTNESS_ZERO, input->keybit);
1914 	set_bit(KEY_DISPLAY_OFF, input->keybit);
1915 
1916 	error = input_register_device(input);
1917 	if (error)
1918 		goto err_stop_dev;
1919 
1920 	mutex_lock(&video->device_list_lock);
1921 	list_for_each_entry(dev, &video->video_device_list, entry)
1922 		acpi_video_dev_add_notify_handler(dev);
1923 	mutex_unlock(&video->device_list_lock);
1924 
1925 	return 0;
1926 
1927 err_stop_dev:
1928 	acpi_video_bus_stop_devices(video);
1929 err_free_input:
1930 	input_free_device(input);
1931 	video->input = NULL;
1932 out:
1933 	return error;
1934 }
1935 
1936 static void acpi_video_dev_remove_notify_handler(struct acpi_video_device *dev)
1937 {
1938 	if (dev->flags.notify) {
1939 		acpi_remove_notify_handler(dev->dev->handle, ACPI_DEVICE_NOTIFY,
1940 					   acpi_video_device_notify);
1941 		dev->flags.notify = 0;
1942 	}
1943 }
1944 
1945 static void acpi_video_bus_remove_notify_handler(struct acpi_video_bus *video)
1946 {
1947 	struct acpi_video_device *dev;
1948 
1949 	mutex_lock(&video->device_list_lock);
1950 	list_for_each_entry(dev, &video->video_device_list, entry)
1951 		acpi_video_dev_remove_notify_handler(dev);
1952 	mutex_unlock(&video->device_list_lock);
1953 
1954 	acpi_video_bus_stop_devices(video);
1955 	input_unregister_device(video->input);
1956 	video->input = NULL;
1957 }
1958 
1959 static int acpi_video_bus_put_devices(struct acpi_video_bus *video)
1960 {
1961 	struct acpi_video_device *dev, *next;
1962 
1963 	mutex_lock(&video->device_list_lock);
1964 	list_for_each_entry_safe(dev, next, &video->video_device_list, entry) {
1965 		list_del(&dev->entry);
1966 		kfree(dev);
1967 	}
1968 	mutex_unlock(&video->device_list_lock);
1969 
1970 	return 0;
1971 }
1972 
1973 static int instance;
1974 
1975 static int acpi_video_bus_add(struct acpi_device *device)
1976 {
1977 	struct acpi_video_bus *video;
1978 	bool auto_detect;
1979 	int error;
1980 	acpi_status status;
1981 
1982 	status = acpi_walk_namespace(ACPI_TYPE_DEVICE,
1983 				acpi_dev_parent(device)->handle, 1,
1984 				acpi_video_bus_match, NULL,
1985 				device, NULL);
1986 	if (status == AE_ALREADY_EXISTS) {
1987 		pr_info(FW_BUG
1988 			"Duplicate ACPI video bus devices for the"
1989 			" same VGA controller, please try module "
1990 			"parameter \"video.allow_duplicates=1\""
1991 			"if the current driver doesn't work.\n");
1992 		if (!allow_duplicates)
1993 			return -ENODEV;
1994 	}
1995 
1996 	video = kzalloc(sizeof(struct acpi_video_bus), GFP_KERNEL);
1997 	if (!video)
1998 		return -ENOMEM;
1999 
2000 	/* a hack to fix the duplicate name "VID" problem on T61 */
2001 	if (!strcmp(device->pnp.bus_id, "VID")) {
2002 		if (instance)
2003 			device->pnp.bus_id[3] = '0' + instance;
2004 		instance++;
2005 	}
2006 	/* a hack to fix the duplicate name "VGA" problem on Pa 3553 */
2007 	if (!strcmp(device->pnp.bus_id, "VGA")) {
2008 		if (instance)
2009 			device->pnp.bus_id[3] = '0' + instance;
2010 		instance++;
2011 	}
2012 
2013 	video->device = device;
2014 	strcpy(acpi_device_name(device), ACPI_VIDEO_BUS_NAME);
2015 	strcpy(acpi_device_class(device), ACPI_VIDEO_CLASS);
2016 	device->driver_data = video;
2017 
2018 	acpi_video_bus_find_cap(video);
2019 	error = acpi_video_bus_check(video);
2020 	if (error)
2021 		goto err_free_video;
2022 
2023 	mutex_init(&video->device_list_lock);
2024 	INIT_LIST_HEAD(&video->video_device_list);
2025 
2026 	error = acpi_video_bus_get_devices(video, device);
2027 	if (error)
2028 		goto err_put_video;
2029 
2030 	/*
2031 	 * HP ZBook Fury 16 G10 requires ACPI video's child devices have _PS0
2032 	 * evaluated to have functional panel brightness control.
2033 	 */
2034 	acpi_device_fix_up_power_extended(device);
2035 
2036 	pr_info("%s [%s] (multi-head: %s  rom: %s  post: %s)\n",
2037 	       ACPI_VIDEO_DEVICE_NAME, acpi_device_bid(device),
2038 	       video->flags.multihead ? "yes" : "no",
2039 	       video->flags.rom ? "yes" : "no",
2040 	       video->flags.post ? "yes" : "no");
2041 	mutex_lock(&video_list_lock);
2042 	list_add_tail(&video->entry, &video_bus_head);
2043 	mutex_unlock(&video_list_lock);
2044 
2045 	/*
2046 	 * If backlight-type auto-detection is used then a native backlight may
2047 	 * show up later and this may change the result from video to native.
2048 	 * Therefor normally the userspace visible /sys/class/backlight device
2049 	 * gets registered separately by the GPU driver calling
2050 	 * acpi_video_register_backlight() when an internal panel is detected.
2051 	 * Register the backlight now when not using auto-detection, so that
2052 	 * when the kernel cmdline or DMI-quirks are used the backlight will
2053 	 * get registered even if acpi_video_register_backlight() is not called.
2054 	 */
2055 	acpi_video_run_bcl_for_osi(video);
2056 	if (__acpi_video_get_backlight_type(false, &auto_detect) == acpi_backlight_video &&
2057 	    !auto_detect)
2058 		acpi_video_bus_register_backlight(video);
2059 
2060 	acpi_video_bus_add_notify_handler(video);
2061 
2062 	error = acpi_dev_install_notify_handler(device, ACPI_DEVICE_NOTIFY,
2063 						acpi_video_bus_notify);
2064 	if (error)
2065 		goto err_remove;
2066 
2067 	return 0;
2068 
2069 err_remove:
2070 	mutex_lock(&video_list_lock);
2071 	list_del(&video->entry);
2072 	mutex_unlock(&video_list_lock);
2073 	acpi_video_bus_remove_notify_handler(video);
2074 	acpi_video_bus_unregister_backlight(video);
2075 err_put_video:
2076 	acpi_video_bus_put_devices(video);
2077 	kfree(video->attached_array);
2078 err_free_video:
2079 	kfree(video);
2080 	device->driver_data = NULL;
2081 
2082 	return error;
2083 }
2084 
2085 static void acpi_video_bus_remove(struct acpi_device *device)
2086 {
2087 	struct acpi_video_bus *video = NULL;
2088 
2089 
2090 	if (!device || !acpi_driver_data(device))
2091 		return;
2092 
2093 	video = acpi_driver_data(device);
2094 
2095 	acpi_dev_remove_notify_handler(device, ACPI_DEVICE_NOTIFY,
2096 				       acpi_video_bus_notify);
2097 
2098 	mutex_lock(&video_list_lock);
2099 	list_del(&video->entry);
2100 	mutex_unlock(&video_list_lock);
2101 
2102 	acpi_video_bus_remove_notify_handler(video);
2103 	acpi_video_bus_unregister_backlight(video);
2104 	acpi_video_bus_put_devices(video);
2105 
2106 	kfree(video->attached_array);
2107 	kfree(video);
2108 }
2109 
2110 static int __init is_i740(struct pci_dev *dev)
2111 {
2112 	if (dev->device == 0x00D1)
2113 		return 1;
2114 	if (dev->device == 0x7000)
2115 		return 1;
2116 	return 0;
2117 }
2118 
2119 static int __init intel_opregion_present(void)
2120 {
2121 	int opregion = 0;
2122 	struct pci_dev *dev = NULL;
2123 	u32 address;
2124 
2125 	for_each_pci_dev(dev) {
2126 		if ((dev->class >> 8) != PCI_CLASS_DISPLAY_VGA)
2127 			continue;
2128 		if (dev->vendor != PCI_VENDOR_ID_INTEL)
2129 			continue;
2130 		/* We don't want to poke around undefined i740 registers */
2131 		if (is_i740(dev))
2132 			continue;
2133 		pci_read_config_dword(dev, 0xfc, &address);
2134 		if (!address)
2135 			continue;
2136 		opregion = 1;
2137 	}
2138 	return opregion;
2139 }
2140 
2141 /* Check if the chassis-type indicates there is no builtin LCD panel */
2142 static bool dmi_is_desktop(void)
2143 {
2144 	const char *chassis_type;
2145 	unsigned long type;
2146 
2147 	chassis_type = dmi_get_system_info(DMI_CHASSIS_TYPE);
2148 	if (!chassis_type)
2149 		return false;
2150 
2151 	if (kstrtoul(chassis_type, 10, &type) != 0)
2152 		return false;
2153 
2154 	switch (type) {
2155 	case 0x03: /* Desktop */
2156 	case 0x04: /* Low Profile Desktop */
2157 	case 0x05: /* Pizza Box */
2158 	case 0x06: /* Mini Tower */
2159 	case 0x07: /* Tower */
2160 	case 0x10: /* Lunch Box */
2161 	case 0x11: /* Main Server Chassis */
2162 		return true;
2163 	}
2164 
2165 	return false;
2166 }
2167 
2168 /*
2169  * We're seeing a lot of bogus backlight interfaces on newer machines
2170  * without a LCD such as desktops, servers and HDMI sticks. Checking the
2171  * lcd flag fixes this, enable this by default on any machines which are:
2172  * 1.  Win8 ready (where we also prefer the native backlight driver, so
2173  *     normally the acpi_video code should not register there anyways); *and*
2174  * 2.1 Report a desktop/server DMI chassis-type, or
2175  * 2.2 Are an ACPI-reduced-hardware platform (and thus won't use the EC for
2176        backlight control)
2177  */
2178 static bool should_check_lcd_flag(void)
2179 {
2180 	if (!acpi_osi_is_win8())
2181 		return false;
2182 
2183 	if (dmi_is_desktop())
2184 		return true;
2185 
2186 	if (acpi_reduced_hardware())
2187 		return true;
2188 
2189 	return false;
2190 }
2191 
2192 int acpi_video_register(void)
2193 {
2194 	int ret = 0;
2195 
2196 	mutex_lock(&register_count_mutex);
2197 	if (register_count) {
2198 		/*
2199 		 * if the function of acpi_video_register is already called,
2200 		 * don't register the acpi_video_bus again and return no error.
2201 		 */
2202 		goto leave;
2203 	}
2204 
2205 	if (only_lcd == -1)
2206 		only_lcd = should_check_lcd_flag();
2207 
2208 	dmi_check_system(video_dmi_table);
2209 
2210 	ret = acpi_bus_register_driver(&acpi_video_bus);
2211 	if (ret)
2212 		goto leave;
2213 
2214 	/*
2215 	 * When the acpi_video_bus is loaded successfully, increase
2216 	 * the counter reference.
2217 	 */
2218 	register_count = 1;
2219 
2220 leave:
2221 	mutex_unlock(&register_count_mutex);
2222 	return ret;
2223 }
2224 EXPORT_SYMBOL(acpi_video_register);
2225 
2226 void acpi_video_unregister(void)
2227 {
2228 	mutex_lock(&register_count_mutex);
2229 	if (register_count) {
2230 		acpi_bus_unregister_driver(&acpi_video_bus);
2231 		register_count = 0;
2232 		may_report_brightness_keys = false;
2233 	}
2234 	mutex_unlock(&register_count_mutex);
2235 }
2236 EXPORT_SYMBOL(acpi_video_unregister);
2237 
2238 void acpi_video_register_backlight(void)
2239 {
2240 	struct acpi_video_bus *video;
2241 
2242 	mutex_lock(&video_list_lock);
2243 	list_for_each_entry(video, &video_bus_head, entry)
2244 		acpi_video_bus_register_backlight(video);
2245 	mutex_unlock(&video_list_lock);
2246 }
2247 EXPORT_SYMBOL(acpi_video_register_backlight);
2248 
2249 bool acpi_video_handles_brightness_key_presses(void)
2250 {
2251 	return may_report_brightness_keys &&
2252 	       (report_key_events & REPORT_BRIGHTNESS_KEY_EVENTS);
2253 }
2254 EXPORT_SYMBOL(acpi_video_handles_brightness_key_presses);
2255 
2256 /*
2257  * This is kind of nasty. Hardware using Intel chipsets may require
2258  * the video opregion code to be run first in order to initialise
2259  * state before any ACPI video calls are made. To handle this we defer
2260  * registration of the video class until the opregion code has run.
2261  */
2262 
2263 static int __init acpi_video_init(void)
2264 {
2265 	/*
2266 	 * Let the module load even if ACPI is disabled (e.g. due to
2267 	 * a broken BIOS) so that i915.ko can still be loaded on such
2268 	 * old systems without an AcpiOpRegion.
2269 	 *
2270 	 * acpi_video_register() will report -ENODEV later as well due
2271 	 * to acpi_disabled when i915.ko tries to register itself afterwards.
2272 	 */
2273 	if (acpi_disabled)
2274 		return 0;
2275 
2276 	if (intel_opregion_present())
2277 		return 0;
2278 
2279 	return acpi_video_register();
2280 }
2281 
2282 static void __exit acpi_video_exit(void)
2283 {
2284 	acpi_video_unregister();
2285 }
2286 
2287 module_init(acpi_video_init);
2288 module_exit(acpi_video_exit);
2289