xref: /openbmc/linux/drivers/acpi/acpi_video.c (revision bbb774d9)
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 static int disable_backlight_sysfs_if = -1;
51 module_param(disable_backlight_sysfs_if, int, 0444);
52 
53 #define REPORT_OUTPUT_KEY_EVENTS		0x01
54 #define REPORT_BRIGHTNESS_KEY_EVENTS		0x02
55 static int report_key_events = -1;
56 module_param(report_key_events, int, 0644);
57 MODULE_PARM_DESC(report_key_events,
58 	"0: none, 1: output changes, 2: brightness changes, 3: all");
59 
60 static int hw_changes_brightness = -1;
61 module_param(hw_changes_brightness, int, 0644);
62 MODULE_PARM_DESC(hw_changes_brightness,
63 	"Set this to 1 on buggy hw which changes the brightness itself when "
64 	"a hotkey is pressed: -1: auto, 0: normal 1: hw-changes-brightness");
65 
66 /*
67  * Whether the struct acpi_video_device_attrib::device_id_scheme bit should be
68  * assumed even if not actually set.
69  */
70 static bool device_id_scheme = false;
71 module_param(device_id_scheme, bool, 0444);
72 
73 static int only_lcd = -1;
74 module_param(only_lcd, int, 0444);
75 
76 static bool may_report_brightness_keys;
77 static int register_count;
78 static DEFINE_MUTEX(register_count_mutex);
79 static DEFINE_MUTEX(video_list_lock);
80 static LIST_HEAD(video_bus_head);
81 static int acpi_video_bus_add(struct acpi_device *device);
82 static int acpi_video_bus_remove(struct acpi_device *device);
83 static void acpi_video_bus_notify(struct acpi_device *device, u32 event);
84 void acpi_video_detect_exit(void);
85 
86 /*
87  * Indices in the _BCL method response: the first two items are special,
88  * the rest are all supported levels.
89  *
90  * See page 575 of the ACPI spec 3.0
91  */
92 enum acpi_video_level_idx {
93 	ACPI_VIDEO_AC_LEVEL,		/* level when machine has full power */
94 	ACPI_VIDEO_BATTERY_LEVEL,	/* level when machine is on batteries */
95 	ACPI_VIDEO_FIRST_LEVEL,		/* actual supported levels begin here */
96 };
97 
98 static const struct acpi_device_id video_device_ids[] = {
99 	{ACPI_VIDEO_HID, 0},
100 	{"", 0},
101 };
102 MODULE_DEVICE_TABLE(acpi, video_device_ids);
103 
104 static struct acpi_driver acpi_video_bus = {
105 	.name = "video",
106 	.class = ACPI_VIDEO_CLASS,
107 	.ids = video_device_ids,
108 	.ops = {
109 		.add = acpi_video_bus_add,
110 		.remove = acpi_video_bus_remove,
111 		.notify = acpi_video_bus_notify,
112 		},
113 };
114 
115 struct acpi_video_bus_flags {
116 	u8 multihead:1;		/* can switch video heads */
117 	u8 rom:1;		/* can retrieve a video rom */
118 	u8 post:1;		/* can configure the head to */
119 	u8 reserved:5;
120 };
121 
122 struct acpi_video_bus_cap {
123 	u8 _DOS:1;		/* Enable/Disable output switching */
124 	u8 _DOD:1;		/* Enumerate all devices attached to display adapter */
125 	u8 _ROM:1;		/* Get ROM Data */
126 	u8 _GPD:1;		/* Get POST Device */
127 	u8 _SPD:1;		/* Set POST Device */
128 	u8 _VPO:1;		/* Video POST Options */
129 	u8 reserved:2;
130 };
131 
132 struct acpi_video_device_attrib {
133 	u32 display_index:4;	/* A zero-based instance of the Display */
134 	u32 display_port_attachment:4;	/* This field differentiates the display type */
135 	u32 display_type:4;	/* Describe the specific type in use */
136 	u32 vendor_specific:4;	/* Chipset Vendor Specific */
137 	u32 bios_can_detect:1;	/* BIOS can detect the device */
138 	u32 depend_on_vga:1;	/* Non-VGA output device whose power is related to
139 				   the VGA device. */
140 	u32 pipe_id:3;		/* For VGA multiple-head devices. */
141 	u32 reserved:10;	/* Must be 0 */
142 
143 	/*
144 	 * The device ID might not actually follow the scheme described by this
145 	 * struct acpi_video_device_attrib. If it does, then this bit
146 	 * device_id_scheme is set; otherwise, other fields should be ignored.
147 	 *
148 	 * (but also see the global flag device_id_scheme)
149 	 */
150 	u32 device_id_scheme:1;
151 };
152 
153 struct acpi_video_enumerated_device {
154 	union {
155 		u32 int_val;
156 		struct acpi_video_device_attrib attrib;
157 	} value;
158 	struct acpi_video_device *bind_info;
159 };
160 
161 struct acpi_video_bus {
162 	struct acpi_device *device;
163 	bool backlight_registered;
164 	u8 dos_setting;
165 	struct acpi_video_enumerated_device *attached_array;
166 	u8 attached_count;
167 	u8 child_count;
168 	struct acpi_video_bus_cap cap;
169 	struct acpi_video_bus_flags flags;
170 	struct list_head video_device_list;
171 	struct mutex device_list_lock;	/* protects video_device_list */
172 	struct list_head entry;
173 	struct input_dev *input;
174 	char phys[32];	/* for input device */
175 	struct notifier_block pm_nb;
176 };
177 
178 struct acpi_video_device_flags {
179 	u8 crt:1;
180 	u8 lcd:1;
181 	u8 tvout:1;
182 	u8 dvi:1;
183 	u8 bios:1;
184 	u8 unknown:1;
185 	u8 notify:1;
186 	u8 reserved:1;
187 };
188 
189 struct acpi_video_device_cap {
190 	u8 _ADR:1;		/* Return the unique ID */
191 	u8 _BCL:1;		/* Query list of brightness control levels supported */
192 	u8 _BCM:1;		/* Set the brightness level */
193 	u8 _BQC:1;		/* Get current brightness level */
194 	u8 _BCQ:1;		/* Some buggy BIOS uses _BCQ instead of _BQC */
195 	u8 _DDC:1;		/* Return the EDID for this device */
196 };
197 
198 struct acpi_video_device {
199 	unsigned long device_id;
200 	struct acpi_video_device_flags flags;
201 	struct acpi_video_device_cap cap;
202 	struct list_head entry;
203 	struct delayed_work switch_brightness_work;
204 	int switch_brightness_event;
205 	struct acpi_video_bus *video;
206 	struct acpi_device *dev;
207 	struct acpi_video_device_brightness *brightness;
208 	struct backlight_device *backlight;
209 	struct thermal_cooling_device *cooling_dev;
210 };
211 
212 static void acpi_video_device_notify(acpi_handle handle, u32 event, void *data);
213 static void acpi_video_device_rebind(struct acpi_video_bus *video);
214 static void acpi_video_device_bind(struct acpi_video_bus *video,
215 				   struct acpi_video_device *device);
216 static int acpi_video_device_enumerate(struct acpi_video_bus *video);
217 static int acpi_video_device_lcd_set_level(struct acpi_video_device *device,
218 			int level);
219 static int acpi_video_device_lcd_get_level_current(
220 			struct acpi_video_device *device,
221 			unsigned long long *level, bool raw);
222 static int acpi_video_get_next_level(struct acpi_video_device *device,
223 				     u32 level_current, u32 event);
224 static void acpi_video_switch_brightness(struct work_struct *work);
225 
226 /* backlight device sysfs support */
227 static int acpi_video_get_brightness(struct backlight_device *bd)
228 {
229 	unsigned long long cur_level;
230 	int i;
231 	struct acpi_video_device *vd = bl_get_data(bd);
232 
233 	if (acpi_video_device_lcd_get_level_current(vd, &cur_level, false))
234 		return -EINVAL;
235 	for (i = ACPI_VIDEO_FIRST_LEVEL; i < vd->brightness->count; i++) {
236 		if (vd->brightness->levels[i] == cur_level)
237 			return i - ACPI_VIDEO_FIRST_LEVEL;
238 	}
239 	return 0;
240 }
241 
242 static int acpi_video_set_brightness(struct backlight_device *bd)
243 {
244 	int request_level = bd->props.brightness + ACPI_VIDEO_FIRST_LEVEL;
245 	struct acpi_video_device *vd = bl_get_data(bd);
246 
247 	cancel_delayed_work(&vd->switch_brightness_work);
248 	return acpi_video_device_lcd_set_level(vd,
249 				vd->brightness->levels[request_level]);
250 }
251 
252 static const struct backlight_ops acpi_backlight_ops = {
253 	.get_brightness = acpi_video_get_brightness,
254 	.update_status  = acpi_video_set_brightness,
255 };
256 
257 /* thermal cooling device callbacks */
258 static int video_get_max_state(struct thermal_cooling_device *cooling_dev,
259 			       unsigned long *state)
260 {
261 	struct acpi_device *device = cooling_dev->devdata;
262 	struct acpi_video_device *video = acpi_driver_data(device);
263 
264 	*state = video->brightness->count - ACPI_VIDEO_FIRST_LEVEL - 1;
265 	return 0;
266 }
267 
268 static int video_get_cur_state(struct thermal_cooling_device *cooling_dev,
269 			       unsigned long *state)
270 {
271 	struct acpi_device *device = cooling_dev->devdata;
272 	struct acpi_video_device *video = acpi_driver_data(device);
273 	unsigned long long level;
274 	int offset;
275 
276 	if (acpi_video_device_lcd_get_level_current(video, &level, false))
277 		return -EINVAL;
278 	for (offset = ACPI_VIDEO_FIRST_LEVEL; offset < video->brightness->count;
279 	     offset++)
280 		if (level == video->brightness->levels[offset]) {
281 			*state = video->brightness->count - offset - 1;
282 			return 0;
283 		}
284 
285 	return -EINVAL;
286 }
287 
288 static int
289 video_set_cur_state(struct thermal_cooling_device *cooling_dev, unsigned long state)
290 {
291 	struct acpi_device *device = cooling_dev->devdata;
292 	struct acpi_video_device *video = acpi_driver_data(device);
293 	int level;
294 
295 	if (state >= video->brightness->count - ACPI_VIDEO_FIRST_LEVEL)
296 		return -EINVAL;
297 
298 	state = video->brightness->count - state;
299 	level = video->brightness->levels[state - 1];
300 	return acpi_video_device_lcd_set_level(video, level);
301 }
302 
303 static const struct thermal_cooling_device_ops video_cooling_ops = {
304 	.get_max_state = video_get_max_state,
305 	.get_cur_state = video_get_cur_state,
306 	.set_cur_state = video_set_cur_state,
307 };
308 
309 /*
310  * --------------------------------------------------------------------------
311  *                             Video Management
312  * --------------------------------------------------------------------------
313  */
314 
315 static int
316 acpi_video_device_lcd_query_levels(acpi_handle handle,
317 				   union acpi_object **levels)
318 {
319 	int status;
320 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
321 	union acpi_object *obj;
322 
323 
324 	*levels = NULL;
325 
326 	status = acpi_evaluate_object(handle, "_BCL", NULL, &buffer);
327 	if (ACPI_FAILURE(status))
328 		return status;
329 	obj = (union acpi_object *)buffer.pointer;
330 	if (!obj || (obj->type != ACPI_TYPE_PACKAGE)) {
331 		acpi_handle_info(handle, "Invalid _BCL data\n");
332 		status = -EFAULT;
333 		goto err;
334 	}
335 
336 	*levels = obj;
337 
338 	return 0;
339 
340 err:
341 	kfree(buffer.pointer);
342 
343 	return status;
344 }
345 
346 static int
347 acpi_video_device_lcd_set_level(struct acpi_video_device *device, int level)
348 {
349 	int status;
350 	int state;
351 
352 	status = acpi_execute_simple_method(device->dev->handle,
353 					    "_BCM", level);
354 	if (ACPI_FAILURE(status)) {
355 		acpi_handle_info(device->dev->handle, "_BCM evaluation failed\n");
356 		return -EIO;
357 	}
358 
359 	device->brightness->curr = level;
360 	for (state = ACPI_VIDEO_FIRST_LEVEL; state < device->brightness->count;
361 	     state++)
362 		if (level == device->brightness->levels[state]) {
363 			if (device->backlight)
364 				device->backlight->props.brightness =
365 					state - ACPI_VIDEO_FIRST_LEVEL;
366 			return 0;
367 		}
368 
369 	acpi_handle_info(device->dev->handle, "Current brightness invalid\n");
370 	return -EINVAL;
371 }
372 
373 /*
374  * For some buggy _BQC methods, we need to add a constant value to
375  * the _BQC return value to get the actual current brightness level
376  */
377 
378 static int bqc_offset_aml_bug_workaround;
379 static int video_set_bqc_offset(const struct dmi_system_id *d)
380 {
381 	bqc_offset_aml_bug_workaround = 9;
382 	return 0;
383 }
384 
385 static int video_disable_backlight_sysfs_if(
386 	const struct dmi_system_id *d)
387 {
388 	if (disable_backlight_sysfs_if == -1)
389 		disable_backlight_sysfs_if = 1;
390 	return 0;
391 }
392 
393 static int video_set_device_id_scheme(const struct dmi_system_id *d)
394 {
395 	device_id_scheme = true;
396 	return 0;
397 }
398 
399 static int video_enable_only_lcd(const struct dmi_system_id *d)
400 {
401 	only_lcd = true;
402 	return 0;
403 }
404 
405 static int video_set_report_key_events(const struct dmi_system_id *id)
406 {
407 	if (report_key_events == -1)
408 		report_key_events = (uintptr_t)id->driver_data;
409 	return 0;
410 }
411 
412 static int video_hw_changes_brightness(
413 	const struct dmi_system_id *d)
414 {
415 	if (hw_changes_brightness == -1)
416 		hw_changes_brightness = 1;
417 	return 0;
418 }
419 
420 static const struct dmi_system_id video_dmi_table[] = {
421 	/*
422 	 * Broken _BQC workaround http://bugzilla.kernel.org/show_bug.cgi?id=13121
423 	 */
424 	{
425 	 .callback = video_set_bqc_offset,
426 	 .ident = "Acer Aspire 5720",
427 	 .matches = {
428 		DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
429 		DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5720"),
430 		},
431 	},
432 	{
433 	 .callback = video_set_bqc_offset,
434 	 .ident = "Acer Aspire 5710Z",
435 	 .matches = {
436 		DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
437 		DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5710Z"),
438 		},
439 	},
440 	{
441 	 .callback = video_set_bqc_offset,
442 	 .ident = "eMachines E510",
443 	 .matches = {
444 		DMI_MATCH(DMI_BOARD_VENDOR, "EMACHINES"),
445 		DMI_MATCH(DMI_PRODUCT_NAME, "eMachines E510"),
446 		},
447 	},
448 	{
449 	 .callback = video_set_bqc_offset,
450 	 .ident = "Acer Aspire 5315",
451 	 .matches = {
452 		DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
453 		DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5315"),
454 		},
455 	},
456 	{
457 	 .callback = video_set_bqc_offset,
458 	 .ident = "Acer Aspire 7720",
459 	 .matches = {
460 		DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
461 		DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 7720"),
462 		},
463 	},
464 
465 	/*
466 	 * Some machines have a broken acpi-video interface for brightness
467 	 * control, but still need an acpi_video_device_lcd_set_level() call
468 	 * on resume to turn the backlight power on.  We Enable backlight
469 	 * control on these systems, but do not register a backlight sysfs
470 	 * as brightness control does not work.
471 	 */
472 	{
473 	 /* https://bugzilla.kernel.org/show_bug.cgi?id=21012 */
474 	 .callback = video_disable_backlight_sysfs_if,
475 	 .ident = "Toshiba Portege R700",
476 	 .matches = {
477 		DMI_MATCH(DMI_SYS_VENDOR, "TOSHIBA"),
478 		DMI_MATCH(DMI_PRODUCT_NAME, "PORTEGE R700"),
479 		},
480 	},
481 	{
482 	 /* https://bugs.freedesktop.org/show_bug.cgi?id=82634 */
483 	 .callback = video_disable_backlight_sysfs_if,
484 	 .ident = "Toshiba Portege R830",
485 	 .matches = {
486 		DMI_MATCH(DMI_SYS_VENDOR, "TOSHIBA"),
487 		DMI_MATCH(DMI_PRODUCT_NAME, "PORTEGE R830"),
488 		},
489 	},
490 	{
491 	 /* https://bugzilla.kernel.org/show_bug.cgi?id=21012 */
492 	 .callback = video_disable_backlight_sysfs_if,
493 	 .ident = "Toshiba Satellite R830",
494 	 .matches = {
495 		DMI_MATCH(DMI_SYS_VENDOR, "TOSHIBA"),
496 		DMI_MATCH(DMI_PRODUCT_NAME, "SATELLITE R830"),
497 		},
498 	},
499 	/*
500 	 * Some machine's _DOD IDs don't have bit 31(Device ID Scheme) set
501 	 * but the IDs actually follow the Device ID Scheme.
502 	 */
503 	{
504 	 /* https://bugzilla.kernel.org/show_bug.cgi?id=104121 */
505 	 .callback = video_set_device_id_scheme,
506 	 .ident = "ESPRIMO Mobile M9410",
507 	 .matches = {
508 		DMI_MATCH(DMI_SYS_VENDOR, "FUJITSU SIEMENS"),
509 		DMI_MATCH(DMI_PRODUCT_NAME, "ESPRIMO Mobile M9410"),
510 		},
511 	},
512 	/*
513 	 * Some machines have multiple video output devices, but only the one
514 	 * that is the type of LCD can do the backlight control so we should not
515 	 * register backlight interface for other video output devices.
516 	 */
517 	{
518 	 /* https://bugzilla.kernel.org/show_bug.cgi?id=104121 */
519 	 .callback = video_enable_only_lcd,
520 	 .ident = "ESPRIMO Mobile M9410",
521 	 .matches = {
522 		DMI_MATCH(DMI_SYS_VENDOR, "FUJITSU SIEMENS"),
523 		DMI_MATCH(DMI_PRODUCT_NAME, "ESPRIMO Mobile M9410"),
524 		},
525 	},
526 	/*
527 	 * Some machines report wrong key events on the acpi-bus, suppress
528 	 * key event reporting on these.  Note this is only intended to work
529 	 * around events which are plain wrong. In some cases we get double
530 	 * events, in this case acpi-video is considered the canonical source
531 	 * and the events from the other source should be filtered. E.g.
532 	 * by calling acpi_video_handles_brightness_key_presses() from the
533 	 * vendor acpi/wmi driver or by using /lib/udev/hwdb.d/60-keyboard.hwdb
534 	 */
535 	{
536 	 .callback = video_set_report_key_events,
537 	 .driver_data = (void *)((uintptr_t)REPORT_OUTPUT_KEY_EVENTS),
538 	 .ident = "Dell Vostro V131",
539 	 .matches = {
540 		DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
541 		DMI_MATCH(DMI_PRODUCT_NAME, "Vostro V131"),
542 		},
543 	},
544 	{
545 	 .callback = video_set_report_key_events,
546 	 .driver_data = (void *)((uintptr_t)REPORT_BRIGHTNESS_KEY_EVENTS),
547 	 .ident = "Dell Vostro 3350",
548 	 .matches = {
549 		DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
550 		DMI_MATCH(DMI_PRODUCT_NAME, "Vostro 3350"),
551 		},
552 	},
553 	/*
554 	 * Some machines change the brightness themselves when a brightness
555 	 * hotkey gets pressed, despite us telling them not to. In this case
556 	 * acpi_video_device_notify() should only call backlight_force_update(
557 	 * BACKLIGHT_UPDATE_HOTKEY) and not do anything else.
558 	 */
559 	{
560 	 /* https://bugzilla.kernel.org/show_bug.cgi?id=204077 */
561 	 .callback = video_hw_changes_brightness,
562 	 .ident = "Packard Bell EasyNote MZ35",
563 	 .matches = {
564 		DMI_MATCH(DMI_SYS_VENDOR, "Packard Bell"),
565 		DMI_MATCH(DMI_PRODUCT_NAME, "EasyNote MZ35"),
566 		},
567 	},
568 	{}
569 };
570 
571 static unsigned long long
572 acpi_video_bqc_value_to_level(struct acpi_video_device *device,
573 			      unsigned long long bqc_value)
574 {
575 	unsigned long long level;
576 
577 	if (device->brightness->flags._BQC_use_index) {
578 		/*
579 		 * _BQC returns an index that doesn't account for the first 2
580 		 * items with special meaning (see enum acpi_video_level_idx),
581 		 * so we need to compensate for that by offsetting ourselves
582 		 */
583 		if (device->brightness->flags._BCL_reversed)
584 			bqc_value = device->brightness->count -
585 				ACPI_VIDEO_FIRST_LEVEL - 1 - bqc_value;
586 
587 		level = device->brightness->levels[bqc_value +
588 						   ACPI_VIDEO_FIRST_LEVEL];
589 	} else {
590 		level = bqc_value;
591 	}
592 
593 	level += bqc_offset_aml_bug_workaround;
594 
595 	return level;
596 }
597 
598 static int
599 acpi_video_device_lcd_get_level_current(struct acpi_video_device *device,
600 					unsigned long long *level, bool raw)
601 {
602 	acpi_status status = AE_OK;
603 	int i;
604 
605 	if (device->cap._BQC || device->cap._BCQ) {
606 		char *buf = device->cap._BQC ? "_BQC" : "_BCQ";
607 
608 		status = acpi_evaluate_integer(device->dev->handle, buf,
609 						NULL, level);
610 		if (ACPI_SUCCESS(status)) {
611 			if (raw) {
612 				/*
613 				 * Caller has indicated he wants the raw
614 				 * value returned by _BQC, so don't furtherly
615 				 * mess with the value.
616 				 */
617 				return 0;
618 			}
619 
620 			*level = acpi_video_bqc_value_to_level(device, *level);
621 
622 			for (i = ACPI_VIDEO_FIRST_LEVEL;
623 			     i < device->brightness->count; i++)
624 				if (device->brightness->levels[i] == *level) {
625 					device->brightness->curr = *level;
626 					return 0;
627 				}
628 			/*
629 			 * BQC returned an invalid level.
630 			 * Stop using it.
631 			 */
632 			acpi_handle_info(device->dev->handle,
633 					 "%s returned an invalid level", buf);
634 			device->cap._BQC = device->cap._BCQ = 0;
635 		} else {
636 			/*
637 			 * Fixme:
638 			 * should we return an error or ignore this failure?
639 			 * dev->brightness->curr is a cached value which stores
640 			 * the correct current backlight level in most cases.
641 			 * ACPI video backlight still works w/ buggy _BQC.
642 			 * http://bugzilla.kernel.org/show_bug.cgi?id=12233
643 			 */
644 			acpi_handle_info(device->dev->handle,
645 					 "%s evaluation failed", buf);
646 			device->cap._BQC = device->cap._BCQ = 0;
647 		}
648 	}
649 
650 	*level = device->brightness->curr;
651 	return 0;
652 }
653 
654 static int
655 acpi_video_device_EDID(struct acpi_video_device *device,
656 		       union acpi_object **edid, ssize_t length)
657 {
658 	int status;
659 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
660 	union acpi_object *obj;
661 	union acpi_object arg0 = { ACPI_TYPE_INTEGER };
662 	struct acpi_object_list args = { 1, &arg0 };
663 
664 
665 	*edid = NULL;
666 
667 	if (!device)
668 		return -ENODEV;
669 	if (length == 128)
670 		arg0.integer.value = 1;
671 	else if (length == 256)
672 		arg0.integer.value = 2;
673 	else
674 		return -EINVAL;
675 
676 	status = acpi_evaluate_object(device->dev->handle, "_DDC", &args, &buffer);
677 	if (ACPI_FAILURE(status))
678 		return -ENODEV;
679 
680 	obj = buffer.pointer;
681 
682 	if (obj && obj->type == ACPI_TYPE_BUFFER)
683 		*edid = obj;
684 	else {
685 		acpi_handle_info(device->dev->handle, "Invalid _DDC data\n");
686 		status = -EFAULT;
687 		kfree(obj);
688 	}
689 
690 	return status;
691 }
692 
693 /* bus */
694 
695 /*
696  *  Arg:
697  *	video		: video bus device pointer
698  *	bios_flag	:
699  *		0.	The system BIOS should NOT automatically switch(toggle)
700  *			the active display output.
701  *		1.	The system BIOS should automatically switch (toggle) the
702  *			active display output. No switch event.
703  *		2.	The _DGS value should be locked.
704  *		3.	The system BIOS should not automatically switch (toggle) the
705  *			active display output, but instead generate the display switch
706  *			event notify code.
707  *	lcd_flag	:
708  *		0.	The system BIOS should automatically control the brightness level
709  *			of the LCD when:
710  *			- the power changes from AC to DC (ACPI appendix B)
711  *			- a brightness hotkey gets pressed (implied by Win7/8 backlight docs)
712  *		1.	The system BIOS should NOT automatically control the brightness
713  *			level of the LCD when:
714  *			- the power changes from AC to DC (ACPI appendix B)
715  *			- a brightness hotkey gets pressed (implied by Win7/8 backlight docs)
716  *  Return Value:
717  *		-EINVAL	wrong arg.
718  */
719 
720 static int
721 acpi_video_bus_DOS(struct acpi_video_bus *video, int bios_flag, int lcd_flag)
722 {
723 	acpi_status status;
724 
725 	if (!video->cap._DOS)
726 		return 0;
727 
728 	if (bios_flag < 0 || bios_flag > 3 || lcd_flag < 0 || lcd_flag > 1)
729 		return -EINVAL;
730 	video->dos_setting = (lcd_flag << 2) | bios_flag;
731 	status = acpi_execute_simple_method(video->device->handle, "_DOS",
732 					    (lcd_flag << 2) | bios_flag);
733 	if (ACPI_FAILURE(status))
734 		return -EIO;
735 
736 	return 0;
737 }
738 
739 /*
740  * Simple comparison function used to sort backlight levels.
741  */
742 
743 static int
744 acpi_video_cmp_level(const void *a, const void *b)
745 {
746 	return *(int *)a - *(int *)b;
747 }
748 
749 /*
750  * Decides if _BQC/_BCQ for this system is usable
751  *
752  * We do this by changing the level first and then read out the current
753  * brightness level, if the value does not match, find out if it is using
754  * index. If not, clear the _BQC/_BCQ capability.
755  */
756 static int acpi_video_bqc_quirk(struct acpi_video_device *device,
757 				int max_level, int current_level)
758 {
759 	struct acpi_video_device_brightness *br = device->brightness;
760 	int result;
761 	unsigned long long level;
762 	int test_level;
763 
764 	/* don't mess with existing known broken systems */
765 	if (bqc_offset_aml_bug_workaround)
766 		return 0;
767 
768 	/*
769 	 * Some systems always report current brightness level as maximum
770 	 * through _BQC, we need to test another value for them. However,
771 	 * there is a subtlety:
772 	 *
773 	 * If the _BCL package ordering is descending, the first level
774 	 * (br->levels[2]) is likely to be 0, and if the number of levels
775 	 * matches the number of steps, we might confuse a returned level to
776 	 * mean the index.
777 	 *
778 	 * For example:
779 	 *
780 	 *     current_level = max_level = 100
781 	 *     test_level = 0
782 	 *     returned level = 100
783 	 *
784 	 * In this case 100 means the level, not the index, and _BCM failed.
785 	 * Still, if the _BCL package ordering is descending, the index of
786 	 * level 0 is also 100, so we assume _BQC is indexed, when it's not.
787 	 *
788 	 * This causes all _BQC calls to return bogus values causing weird
789 	 * behavior from the user's perspective.  For example:
790 	 *
791 	 * xbacklight -set 10; xbacklight -set 20;
792 	 *
793 	 * would flash to 90% and then slowly down to the desired level (20).
794 	 *
795 	 * The solution is simple; test anything other than the first level
796 	 * (e.g. 1).
797 	 */
798 	test_level = current_level == max_level
799 		? br->levels[ACPI_VIDEO_FIRST_LEVEL + 1]
800 		: max_level;
801 
802 	result = acpi_video_device_lcd_set_level(device, test_level);
803 	if (result)
804 		return result;
805 
806 	result = acpi_video_device_lcd_get_level_current(device, &level, true);
807 	if (result)
808 		return result;
809 
810 	if (level != test_level) {
811 		/* buggy _BQC found, need to find out if it uses index */
812 		if (level < br->count) {
813 			if (br->flags._BCL_reversed)
814 				level = br->count - ACPI_VIDEO_FIRST_LEVEL - 1 - level;
815 			if (br->levels[level + ACPI_VIDEO_FIRST_LEVEL] == test_level)
816 				br->flags._BQC_use_index = 1;
817 		}
818 
819 		if (!br->flags._BQC_use_index)
820 			device->cap._BQC = device->cap._BCQ = 0;
821 	}
822 
823 	return 0;
824 }
825 
826 int acpi_video_get_levels(struct acpi_device *device,
827 			  struct acpi_video_device_brightness **dev_br,
828 			  int *pmax_level)
829 {
830 	union acpi_object *obj = NULL;
831 	int i, max_level = 0, count = 0, level_ac_battery = 0;
832 	union acpi_object *o;
833 	struct acpi_video_device_brightness *br = NULL;
834 	int result = 0;
835 	u32 value;
836 
837 	if (ACPI_FAILURE(acpi_video_device_lcd_query_levels(device->handle, &obj))) {
838 		acpi_handle_debug(device->handle,
839 				  "Could not query available LCD brightness level\n");
840 		result = -ENODEV;
841 		goto out;
842 	}
843 
844 	if (obj->package.count < ACPI_VIDEO_FIRST_LEVEL) {
845 		result = -EINVAL;
846 		goto out;
847 	}
848 
849 	br = kzalloc(sizeof(*br), GFP_KERNEL);
850 	if (!br) {
851 		result = -ENOMEM;
852 		goto out;
853 	}
854 
855 	/*
856 	 * Note that we have to reserve 2 extra items (ACPI_VIDEO_FIRST_LEVEL),
857 	 * in order to account for buggy BIOS which don't export the first two
858 	 * special levels (see below)
859 	 */
860 	br->levels = kmalloc_array(obj->package.count + ACPI_VIDEO_FIRST_LEVEL,
861 				   sizeof(*br->levels),
862 				   GFP_KERNEL);
863 	if (!br->levels) {
864 		result = -ENOMEM;
865 		goto out_free;
866 	}
867 
868 	for (i = 0; i < obj->package.count; i++) {
869 		o = (union acpi_object *)&obj->package.elements[i];
870 		if (o->type != ACPI_TYPE_INTEGER) {
871 			acpi_handle_info(device->handle, "Invalid data\n");
872 			continue;
873 		}
874 		value = (u32) o->integer.value;
875 		/* Skip duplicate entries */
876 		if (count > ACPI_VIDEO_FIRST_LEVEL
877 		    && br->levels[count - 1] == value)
878 			continue;
879 
880 		br->levels[count] = value;
881 
882 		if (br->levels[count] > max_level)
883 			max_level = br->levels[count];
884 		count++;
885 	}
886 
887 	/*
888 	 * some buggy BIOS don't export the levels
889 	 * when machine is on AC/Battery in _BCL package.
890 	 * In this case, the first two elements in _BCL packages
891 	 * are also supported brightness levels that OS should take care of.
892 	 */
893 	for (i = ACPI_VIDEO_FIRST_LEVEL; i < count; i++) {
894 		if (br->levels[i] == br->levels[ACPI_VIDEO_AC_LEVEL])
895 			level_ac_battery++;
896 		if (br->levels[i] == br->levels[ACPI_VIDEO_BATTERY_LEVEL])
897 			level_ac_battery++;
898 	}
899 
900 	if (level_ac_battery < ACPI_VIDEO_FIRST_LEVEL) {
901 		level_ac_battery = ACPI_VIDEO_FIRST_LEVEL - level_ac_battery;
902 		br->flags._BCL_no_ac_battery_levels = 1;
903 		for (i = (count - 1 + level_ac_battery);
904 		     i >= ACPI_VIDEO_FIRST_LEVEL; i--)
905 			br->levels[i] = br->levels[i - level_ac_battery];
906 		count += level_ac_battery;
907 	} else if (level_ac_battery > ACPI_VIDEO_FIRST_LEVEL)
908 		acpi_handle_info(device->handle,
909 				 "Too many duplicates in _BCL package");
910 
911 	/* Check if the _BCL package is in a reversed order */
912 	if (max_level == br->levels[ACPI_VIDEO_FIRST_LEVEL]) {
913 		br->flags._BCL_reversed = 1;
914 		sort(&br->levels[ACPI_VIDEO_FIRST_LEVEL],
915 		     count - ACPI_VIDEO_FIRST_LEVEL,
916 		     sizeof(br->levels[ACPI_VIDEO_FIRST_LEVEL]),
917 		     acpi_video_cmp_level, NULL);
918 	} else if (max_level != br->levels[count - 1])
919 		acpi_handle_info(device->handle,
920 				 "Found unordered _BCL package");
921 
922 	br->count = count;
923 	*dev_br = br;
924 	if (pmax_level)
925 		*pmax_level = max_level;
926 
927 out:
928 	kfree(obj);
929 	return result;
930 out_free:
931 	kfree(br);
932 	goto out;
933 }
934 EXPORT_SYMBOL(acpi_video_get_levels);
935 
936 /*
937  *  Arg:
938  *	device	: video output device (LCD, CRT, ..)
939  *
940  *  Return Value:
941  *	Maximum brightness level
942  *
943  *  Allocate and initialize device->brightness.
944  */
945 
946 static int
947 acpi_video_init_brightness(struct acpi_video_device *device)
948 {
949 	int i, max_level = 0;
950 	unsigned long long level, level_old;
951 	struct acpi_video_device_brightness *br = NULL;
952 	int result;
953 
954 	result = acpi_video_get_levels(device->dev, &br, &max_level);
955 	if (result)
956 		return result;
957 	device->brightness = br;
958 
959 	/* _BQC uses INDEX while _BCL uses VALUE in some laptops */
960 	br->curr = level = max_level;
961 
962 	if (!device->cap._BQC)
963 		goto set_level;
964 
965 	result = acpi_video_device_lcd_get_level_current(device,
966 							 &level_old, true);
967 	if (result)
968 		goto out_free_levels;
969 
970 	result = acpi_video_bqc_quirk(device, max_level, level_old);
971 	if (result)
972 		goto out_free_levels;
973 	/*
974 	 * cap._BQC may get cleared due to _BQC is found to be broken
975 	 * in acpi_video_bqc_quirk, so check again here.
976 	 */
977 	if (!device->cap._BQC)
978 		goto set_level;
979 
980 	level = acpi_video_bqc_value_to_level(device, level_old);
981 	/*
982 	 * On some buggy laptops, _BQC returns an uninitialized
983 	 * value when invoked for the first time, i.e.
984 	 * level_old is invalid (no matter whether it's a level
985 	 * or an index). Set the backlight to max_level in this case.
986 	 */
987 	for (i = ACPI_VIDEO_FIRST_LEVEL; i < br->count; i++)
988 		if (level == br->levels[i])
989 			break;
990 	if (i == br->count || !level)
991 		level = max_level;
992 
993 set_level:
994 	result = acpi_video_device_lcd_set_level(device, level);
995 	if (result)
996 		goto out_free_levels;
997 
998 	acpi_handle_debug(device->dev->handle, "found %d brightness levels\n",
999 			  br->count - ACPI_VIDEO_FIRST_LEVEL);
1000 
1001 	return 0;
1002 
1003 out_free_levels:
1004 	kfree(br->levels);
1005 	kfree(br);
1006 	device->brightness = NULL;
1007 	return result;
1008 }
1009 
1010 /*
1011  *  Arg:
1012  *	device	: video output device (LCD, CRT, ..)
1013  *
1014  *  Return Value:
1015  *	None
1016  *
1017  *  Find out all required AML methods defined under the output
1018  *  device.
1019  */
1020 
1021 static void acpi_video_device_find_cap(struct acpi_video_device *device)
1022 {
1023 	if (acpi_has_method(device->dev->handle, "_ADR"))
1024 		device->cap._ADR = 1;
1025 	if (acpi_has_method(device->dev->handle, "_BCL"))
1026 		device->cap._BCL = 1;
1027 	if (acpi_has_method(device->dev->handle, "_BCM"))
1028 		device->cap._BCM = 1;
1029 	if (acpi_has_method(device->dev->handle, "_BQC")) {
1030 		device->cap._BQC = 1;
1031 	} else if (acpi_has_method(device->dev->handle, "_BCQ")) {
1032 		acpi_handle_info(device->dev->handle,
1033 				 "_BCQ is used instead of _BQC\n");
1034 		device->cap._BCQ = 1;
1035 	}
1036 
1037 	if (acpi_has_method(device->dev->handle, "_DDC"))
1038 		device->cap._DDC = 1;
1039 }
1040 
1041 /*
1042  *  Arg:
1043  *	device	: video output device (VGA)
1044  *
1045  *  Return Value:
1046  *	None
1047  *
1048  *  Find out all required AML methods defined under the video bus device.
1049  */
1050 
1051 static void acpi_video_bus_find_cap(struct acpi_video_bus *video)
1052 {
1053 	if (acpi_has_method(video->device->handle, "_DOS"))
1054 		video->cap._DOS = 1;
1055 	if (acpi_has_method(video->device->handle, "_DOD"))
1056 		video->cap._DOD = 1;
1057 	if (acpi_has_method(video->device->handle, "_ROM"))
1058 		video->cap._ROM = 1;
1059 	if (acpi_has_method(video->device->handle, "_GPD"))
1060 		video->cap._GPD = 1;
1061 	if (acpi_has_method(video->device->handle, "_SPD"))
1062 		video->cap._SPD = 1;
1063 	if (acpi_has_method(video->device->handle, "_VPO"))
1064 		video->cap._VPO = 1;
1065 }
1066 
1067 /*
1068  * Check whether the video bus device has required AML method to
1069  * support the desired features
1070  */
1071 
1072 static int acpi_video_bus_check(struct acpi_video_bus *video)
1073 {
1074 	acpi_status status = -ENOENT;
1075 	struct pci_dev *dev;
1076 
1077 	if (!video)
1078 		return -EINVAL;
1079 
1080 	dev = acpi_get_pci_dev(video->device->handle);
1081 	if (!dev)
1082 		return -ENODEV;
1083 	pci_dev_put(dev);
1084 
1085 	/*
1086 	 * Since there is no HID, CID and so on for VGA driver, we have
1087 	 * to check well known required nodes.
1088 	 */
1089 
1090 	/* Does this device support video switching? */
1091 	if (video->cap._DOS || video->cap._DOD) {
1092 		if (!video->cap._DOS) {
1093 			pr_info(FW_BUG "ACPI(%s) defines _DOD but not _DOS\n",
1094 				acpi_device_bid(video->device));
1095 		}
1096 		video->flags.multihead = 1;
1097 		status = 0;
1098 	}
1099 
1100 	/* Does this device support retrieving a video ROM? */
1101 	if (video->cap._ROM) {
1102 		video->flags.rom = 1;
1103 		status = 0;
1104 	}
1105 
1106 	/* Does this device support configuring which video device to POST? */
1107 	if (video->cap._GPD && video->cap._SPD && video->cap._VPO) {
1108 		video->flags.post = 1;
1109 		status = 0;
1110 	}
1111 
1112 	return status;
1113 }
1114 
1115 /*
1116  * --------------------------------------------------------------------------
1117  *                               Driver Interface
1118  * --------------------------------------------------------------------------
1119  */
1120 
1121 /* device interface */
1122 static struct acpi_video_device_attrib *
1123 acpi_video_get_device_attr(struct acpi_video_bus *video, unsigned long device_id)
1124 {
1125 	struct acpi_video_enumerated_device *ids;
1126 	int i;
1127 
1128 	for (i = 0; i < video->attached_count; i++) {
1129 		ids = &video->attached_array[i];
1130 		if ((ids->value.int_val & 0xffff) == device_id)
1131 			return &ids->value.attrib;
1132 	}
1133 
1134 	return NULL;
1135 }
1136 
1137 static int
1138 acpi_video_get_device_type(struct acpi_video_bus *video,
1139 			   unsigned long device_id)
1140 {
1141 	struct acpi_video_enumerated_device *ids;
1142 	int i;
1143 
1144 	for (i = 0; i < video->attached_count; i++) {
1145 		ids = &video->attached_array[i];
1146 		if ((ids->value.int_val & 0xffff) == device_id)
1147 			return ids->value.int_val;
1148 	}
1149 
1150 	return 0;
1151 }
1152 
1153 static int acpi_video_bus_get_one_device(struct acpi_device *device, void *arg)
1154 {
1155 	struct acpi_video_bus *video = arg;
1156 	struct acpi_video_device_attrib *attribute;
1157 	struct acpi_video_device *data;
1158 	unsigned long long device_id;
1159 	acpi_status status;
1160 	int device_type;
1161 
1162 	status = acpi_evaluate_integer(device->handle, "_ADR", NULL, &device_id);
1163 	/* Skip devices without _ADR instead of failing. */
1164 	if (ACPI_FAILURE(status))
1165 		goto exit;
1166 
1167 	data = kzalloc(sizeof(struct acpi_video_device), GFP_KERNEL);
1168 	if (!data) {
1169 		dev_dbg(&device->dev, "Cannot attach\n");
1170 		return -ENOMEM;
1171 	}
1172 
1173 	strcpy(acpi_device_name(device), ACPI_VIDEO_DEVICE_NAME);
1174 	strcpy(acpi_device_class(device), ACPI_VIDEO_CLASS);
1175 	device->driver_data = data;
1176 
1177 	data->device_id = device_id;
1178 	data->video = video;
1179 	data->dev = device;
1180 	INIT_DELAYED_WORK(&data->switch_brightness_work,
1181 			  acpi_video_switch_brightness);
1182 
1183 	attribute = acpi_video_get_device_attr(video, device_id);
1184 
1185 	if (attribute && (attribute->device_id_scheme || device_id_scheme)) {
1186 		switch (attribute->display_type) {
1187 		case ACPI_VIDEO_DISPLAY_CRT:
1188 			data->flags.crt = 1;
1189 			break;
1190 		case ACPI_VIDEO_DISPLAY_TV:
1191 			data->flags.tvout = 1;
1192 			break;
1193 		case ACPI_VIDEO_DISPLAY_DVI:
1194 			data->flags.dvi = 1;
1195 			break;
1196 		case ACPI_VIDEO_DISPLAY_LCD:
1197 			data->flags.lcd = 1;
1198 			break;
1199 		default:
1200 			data->flags.unknown = 1;
1201 			break;
1202 		}
1203 		if (attribute->bios_can_detect)
1204 			data->flags.bios = 1;
1205 	} else {
1206 		/* Check for legacy IDs */
1207 		device_type = acpi_video_get_device_type(video, device_id);
1208 		/* Ignore bits 16 and 18-20 */
1209 		switch (device_type & 0xffe2ffff) {
1210 		case ACPI_VIDEO_DISPLAY_LEGACY_MONITOR:
1211 			data->flags.crt = 1;
1212 			break;
1213 		case ACPI_VIDEO_DISPLAY_LEGACY_PANEL:
1214 			data->flags.lcd = 1;
1215 			break;
1216 		case ACPI_VIDEO_DISPLAY_LEGACY_TV:
1217 			data->flags.tvout = 1;
1218 			break;
1219 		default:
1220 			data->flags.unknown = 1;
1221 		}
1222 	}
1223 
1224 	acpi_video_device_bind(video, data);
1225 	acpi_video_device_find_cap(data);
1226 
1227 	if (data->cap._BCM && data->cap._BCL)
1228 		may_report_brightness_keys = true;
1229 
1230 	mutex_lock(&video->device_list_lock);
1231 	list_add_tail(&data->entry, &video->video_device_list);
1232 	mutex_unlock(&video->device_list_lock);
1233 
1234 exit:
1235 	video->child_count++;
1236 	return 0;
1237 }
1238 
1239 /*
1240  *  Arg:
1241  *	video	: video bus device
1242  *
1243  *  Return:
1244  *	none
1245  *
1246  *  Enumerate the video device list of the video bus,
1247  *  bind the ids with the corresponding video devices
1248  *  under the video bus.
1249  */
1250 
1251 static void acpi_video_device_rebind(struct acpi_video_bus *video)
1252 {
1253 	struct acpi_video_device *dev;
1254 
1255 	mutex_lock(&video->device_list_lock);
1256 
1257 	list_for_each_entry(dev, &video->video_device_list, entry)
1258 		acpi_video_device_bind(video, dev);
1259 
1260 	mutex_unlock(&video->device_list_lock);
1261 }
1262 
1263 /*
1264  *  Arg:
1265  *	video	: video bus device
1266  *	device	: video output device under the video
1267  *		bus
1268  *
1269  *  Return:
1270  *	none
1271  *
1272  *  Bind the ids with the corresponding video devices
1273  *  under the video bus.
1274  */
1275 
1276 static void
1277 acpi_video_device_bind(struct acpi_video_bus *video,
1278 		       struct acpi_video_device *device)
1279 {
1280 	struct acpi_video_enumerated_device *ids;
1281 	int i;
1282 
1283 	for (i = 0; i < video->attached_count; i++) {
1284 		ids = &video->attached_array[i];
1285 		if (device->device_id == (ids->value.int_val & 0xffff)) {
1286 			ids->bind_info = device;
1287 			acpi_handle_debug(video->device->handle, "%s: %d\n",
1288 					  __func__, i);
1289 		}
1290 	}
1291 }
1292 
1293 static bool acpi_video_device_in_dod(struct acpi_video_device *device)
1294 {
1295 	struct acpi_video_bus *video = device->video;
1296 	int i;
1297 
1298 	/*
1299 	 * If we have a broken _DOD or we have more than 8 output devices
1300 	 * under the graphics controller node that we can't proper deal with
1301 	 * in the operation region code currently, no need to test.
1302 	 */
1303 	if (!video->attached_count || video->child_count > 8)
1304 		return true;
1305 
1306 	for (i = 0; i < video->attached_count; i++) {
1307 		if ((video->attached_array[i].value.int_val & 0xfff) ==
1308 		    (device->device_id & 0xfff))
1309 			return true;
1310 	}
1311 
1312 	return false;
1313 }
1314 
1315 /*
1316  *  Arg:
1317  *	video	: video bus device
1318  *
1319  *  Return:
1320  *	< 0	: error
1321  *
1322  *  Call _DOD to enumerate all devices attached to display adapter
1323  *
1324  */
1325 
1326 static int acpi_video_device_enumerate(struct acpi_video_bus *video)
1327 {
1328 	int status;
1329 	int count;
1330 	int i;
1331 	struct acpi_video_enumerated_device *active_list;
1332 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
1333 	union acpi_object *dod = NULL;
1334 	union acpi_object *obj;
1335 
1336 	if (!video->cap._DOD)
1337 		return AE_NOT_EXIST;
1338 
1339 	status = acpi_evaluate_object(video->device->handle, "_DOD", NULL, &buffer);
1340 	if (ACPI_FAILURE(status)) {
1341 		acpi_handle_info(video->device->handle,
1342 				 "_DOD evaluation failed: %s\n",
1343 				 acpi_format_exception(status));
1344 		return status;
1345 	}
1346 
1347 	dod = buffer.pointer;
1348 	if (!dod || (dod->type != ACPI_TYPE_PACKAGE)) {
1349 		acpi_handle_info(video->device->handle, "Invalid _DOD data\n");
1350 		status = -EFAULT;
1351 		goto out;
1352 	}
1353 
1354 	acpi_handle_debug(video->device->handle, "Found %d video heads in _DOD\n",
1355 			  dod->package.count);
1356 
1357 	active_list = kcalloc(1 + dod->package.count,
1358 			      sizeof(struct acpi_video_enumerated_device),
1359 			      GFP_KERNEL);
1360 	if (!active_list) {
1361 		status = -ENOMEM;
1362 		goto out;
1363 	}
1364 
1365 	count = 0;
1366 	for (i = 0; i < dod->package.count; i++) {
1367 		obj = &dod->package.elements[i];
1368 
1369 		if (obj->type != ACPI_TYPE_INTEGER) {
1370 			acpi_handle_info(video->device->handle,
1371 					 "Invalid _DOD data in element %d\n", i);
1372 			continue;
1373 		}
1374 
1375 		active_list[count].value.int_val = obj->integer.value;
1376 		active_list[count].bind_info = NULL;
1377 
1378 		acpi_handle_debug(video->device->handle,
1379 				  "_DOD element[%d] = %d\n", i,
1380 				  (int)obj->integer.value);
1381 
1382 		count++;
1383 	}
1384 
1385 	kfree(video->attached_array);
1386 
1387 	video->attached_array = active_list;
1388 	video->attached_count = count;
1389 
1390 out:
1391 	kfree(buffer.pointer);
1392 	return status;
1393 }
1394 
1395 static int
1396 acpi_video_get_next_level(struct acpi_video_device *device,
1397 			  u32 level_current, u32 event)
1398 {
1399 	int min, max, min_above, max_below, i, l, delta = 255;
1400 	max = max_below = 0;
1401 	min = min_above = 255;
1402 	/* Find closest level to level_current */
1403 	for (i = ACPI_VIDEO_FIRST_LEVEL; i < device->brightness->count; i++) {
1404 		l = device->brightness->levels[i];
1405 		if (abs(l - level_current) < abs(delta)) {
1406 			delta = l - level_current;
1407 			if (!delta)
1408 				break;
1409 		}
1410 	}
1411 	/* Adjust level_current to closest available level */
1412 	level_current += delta;
1413 	for (i = ACPI_VIDEO_FIRST_LEVEL; i < device->brightness->count; i++) {
1414 		l = device->brightness->levels[i];
1415 		if (l < min)
1416 			min = l;
1417 		if (l > max)
1418 			max = l;
1419 		if (l < min_above && l > level_current)
1420 			min_above = l;
1421 		if (l > max_below && l < level_current)
1422 			max_below = l;
1423 	}
1424 
1425 	switch (event) {
1426 	case ACPI_VIDEO_NOTIFY_CYCLE_BRIGHTNESS:
1427 		return (level_current < max) ? min_above : min;
1428 	case ACPI_VIDEO_NOTIFY_INC_BRIGHTNESS:
1429 		return (level_current < max) ? min_above : max;
1430 	case ACPI_VIDEO_NOTIFY_DEC_BRIGHTNESS:
1431 		return (level_current > min) ? max_below : min;
1432 	case ACPI_VIDEO_NOTIFY_ZERO_BRIGHTNESS:
1433 	case ACPI_VIDEO_NOTIFY_DISPLAY_OFF:
1434 		return 0;
1435 	default:
1436 		return level_current;
1437 	}
1438 }
1439 
1440 static void
1441 acpi_video_switch_brightness(struct work_struct *work)
1442 {
1443 	struct acpi_video_device *device = container_of(to_delayed_work(work),
1444 			     struct acpi_video_device, switch_brightness_work);
1445 	unsigned long long level_current, level_next;
1446 	int event = device->switch_brightness_event;
1447 	int result = -EINVAL;
1448 
1449 	/* no warning message if acpi_backlight=vendor or a quirk is used */
1450 	if (!device->backlight)
1451 		return;
1452 
1453 	if (!device->brightness)
1454 		goto out;
1455 
1456 	result = acpi_video_device_lcd_get_level_current(device,
1457 							 &level_current,
1458 							 false);
1459 	if (result)
1460 		goto out;
1461 
1462 	level_next = acpi_video_get_next_level(device, level_current, event);
1463 
1464 	result = acpi_video_device_lcd_set_level(device, level_next);
1465 
1466 	if (!result)
1467 		backlight_force_update(device->backlight,
1468 				       BACKLIGHT_UPDATE_HOTKEY);
1469 
1470 out:
1471 	if (result)
1472 		acpi_handle_info(device->dev->handle,
1473 				 "Failed to switch brightness\n");
1474 }
1475 
1476 int acpi_video_get_edid(struct acpi_device *device, int type, int device_id,
1477 			void **edid)
1478 {
1479 	struct acpi_video_bus *video;
1480 	struct acpi_video_device *video_device;
1481 	union acpi_object *buffer = NULL;
1482 	acpi_status status;
1483 	int i, length;
1484 
1485 	if (!device || !acpi_driver_data(device))
1486 		return -EINVAL;
1487 
1488 	video = acpi_driver_data(device);
1489 
1490 	for (i = 0; i < video->attached_count; i++) {
1491 		video_device = video->attached_array[i].bind_info;
1492 		length = 256;
1493 
1494 		if (!video_device)
1495 			continue;
1496 
1497 		if (!video_device->cap._DDC)
1498 			continue;
1499 
1500 		if (type) {
1501 			switch (type) {
1502 			case ACPI_VIDEO_DISPLAY_CRT:
1503 				if (!video_device->flags.crt)
1504 					continue;
1505 				break;
1506 			case ACPI_VIDEO_DISPLAY_TV:
1507 				if (!video_device->flags.tvout)
1508 					continue;
1509 				break;
1510 			case ACPI_VIDEO_DISPLAY_DVI:
1511 				if (!video_device->flags.dvi)
1512 					continue;
1513 				break;
1514 			case ACPI_VIDEO_DISPLAY_LCD:
1515 				if (!video_device->flags.lcd)
1516 					continue;
1517 				break;
1518 			}
1519 		} else if (video_device->device_id != device_id) {
1520 			continue;
1521 		}
1522 
1523 		status = acpi_video_device_EDID(video_device, &buffer, length);
1524 
1525 		if (ACPI_FAILURE(status) || !buffer ||
1526 		    buffer->type != ACPI_TYPE_BUFFER) {
1527 			length = 128;
1528 			status = acpi_video_device_EDID(video_device, &buffer,
1529 							length);
1530 			if (ACPI_FAILURE(status) || !buffer ||
1531 			    buffer->type != ACPI_TYPE_BUFFER) {
1532 				continue;
1533 			}
1534 		}
1535 
1536 		*edid = buffer->buffer.pointer;
1537 		return length;
1538 	}
1539 
1540 	return -ENODEV;
1541 }
1542 EXPORT_SYMBOL(acpi_video_get_edid);
1543 
1544 static int
1545 acpi_video_bus_get_devices(struct acpi_video_bus *video,
1546 			   struct acpi_device *device)
1547 {
1548 	/*
1549 	 * There are systems where video module known to work fine regardless
1550 	 * of broken _DOD and ignoring returned value here doesn't cause
1551 	 * any issues later.
1552 	 */
1553 	acpi_video_device_enumerate(video);
1554 
1555 	return acpi_dev_for_each_child(device, acpi_video_bus_get_one_device, video);
1556 }
1557 
1558 /* acpi_video interface */
1559 
1560 /*
1561  * Win8 requires setting bit2 of _DOS to let firmware know it shouldn't
1562  * perform any automatic brightness change on receiving a notification.
1563  */
1564 static int acpi_video_bus_start_devices(struct acpi_video_bus *video)
1565 {
1566 	return acpi_video_bus_DOS(video, 0,
1567 				  acpi_osi_is_win8() ? 1 : 0);
1568 }
1569 
1570 static int acpi_video_bus_stop_devices(struct acpi_video_bus *video)
1571 {
1572 	return acpi_video_bus_DOS(video, 0,
1573 				  acpi_osi_is_win8() ? 0 : 1);
1574 }
1575 
1576 static void acpi_video_bus_notify(struct acpi_device *device, u32 event)
1577 {
1578 	struct acpi_video_bus *video = acpi_driver_data(device);
1579 	struct input_dev *input;
1580 	int keycode = 0;
1581 
1582 	if (!video || !video->input)
1583 		return;
1584 
1585 	input = video->input;
1586 
1587 	switch (event) {
1588 	case ACPI_VIDEO_NOTIFY_SWITCH:	/* User requested a switch,
1589 					 * most likely via hotkey. */
1590 		keycode = KEY_SWITCHVIDEOMODE;
1591 		break;
1592 
1593 	case ACPI_VIDEO_NOTIFY_PROBE:	/* User plugged in or removed a video
1594 					 * connector. */
1595 		acpi_video_device_enumerate(video);
1596 		acpi_video_device_rebind(video);
1597 		keycode = KEY_SWITCHVIDEOMODE;
1598 		break;
1599 
1600 	case ACPI_VIDEO_NOTIFY_CYCLE:	/* Cycle Display output hotkey pressed. */
1601 		keycode = KEY_SWITCHVIDEOMODE;
1602 		break;
1603 	case ACPI_VIDEO_NOTIFY_NEXT_OUTPUT:	/* Next Display output hotkey pressed. */
1604 		keycode = KEY_VIDEO_NEXT;
1605 		break;
1606 	case ACPI_VIDEO_NOTIFY_PREV_OUTPUT:	/* previous Display output hotkey pressed. */
1607 		keycode = KEY_VIDEO_PREV;
1608 		break;
1609 
1610 	default:
1611 		acpi_handle_debug(device->handle, "Unsupported event [0x%x]\n",
1612 				  event);
1613 		break;
1614 	}
1615 
1616 	if (acpi_notifier_call_chain(device, event, 0))
1617 		/* Something vetoed the keypress. */
1618 		keycode = 0;
1619 
1620 	if (keycode && (report_key_events & REPORT_OUTPUT_KEY_EVENTS)) {
1621 		input_report_key(input, keycode, 1);
1622 		input_sync(input);
1623 		input_report_key(input, keycode, 0);
1624 		input_sync(input);
1625 	}
1626 }
1627 
1628 static void brightness_switch_event(struct acpi_video_device *video_device,
1629 				    u32 event)
1630 {
1631 	if (!brightness_switch_enabled)
1632 		return;
1633 
1634 	video_device->switch_brightness_event = event;
1635 	schedule_delayed_work(&video_device->switch_brightness_work, HZ / 10);
1636 }
1637 
1638 static void acpi_video_device_notify(acpi_handle handle, u32 event, void *data)
1639 {
1640 	struct acpi_video_device *video_device = data;
1641 	struct acpi_device *device = NULL;
1642 	struct acpi_video_bus *bus;
1643 	struct input_dev *input;
1644 	int keycode = 0;
1645 
1646 	if (!video_device)
1647 		return;
1648 
1649 	device = video_device->dev;
1650 	bus = video_device->video;
1651 	input = bus->input;
1652 
1653 	if (hw_changes_brightness > 0) {
1654 		if (video_device->backlight)
1655 			backlight_force_update(video_device->backlight,
1656 					       BACKLIGHT_UPDATE_HOTKEY);
1657 		acpi_notifier_call_chain(device, event, 0);
1658 		return;
1659 	}
1660 
1661 	switch (event) {
1662 	case ACPI_VIDEO_NOTIFY_CYCLE_BRIGHTNESS:	/* Cycle brightness */
1663 		brightness_switch_event(video_device, event);
1664 		keycode = KEY_BRIGHTNESS_CYCLE;
1665 		break;
1666 	case ACPI_VIDEO_NOTIFY_INC_BRIGHTNESS:	/* Increase brightness */
1667 		brightness_switch_event(video_device, event);
1668 		keycode = KEY_BRIGHTNESSUP;
1669 		break;
1670 	case ACPI_VIDEO_NOTIFY_DEC_BRIGHTNESS:	/* Decrease brightness */
1671 		brightness_switch_event(video_device, event);
1672 		keycode = KEY_BRIGHTNESSDOWN;
1673 		break;
1674 	case ACPI_VIDEO_NOTIFY_ZERO_BRIGHTNESS:	/* zero brightness */
1675 		brightness_switch_event(video_device, event);
1676 		keycode = KEY_BRIGHTNESS_ZERO;
1677 		break;
1678 	case ACPI_VIDEO_NOTIFY_DISPLAY_OFF:	/* display device off */
1679 		brightness_switch_event(video_device, event);
1680 		keycode = KEY_DISPLAY_OFF;
1681 		break;
1682 	default:
1683 		acpi_handle_debug(handle, "Unsupported event [0x%x]\n", event);
1684 		break;
1685 	}
1686 
1687 	if (keycode)
1688 		may_report_brightness_keys = true;
1689 
1690 	acpi_notifier_call_chain(device, event, 0);
1691 
1692 	if (keycode && (report_key_events & REPORT_BRIGHTNESS_KEY_EVENTS)) {
1693 		input_report_key(input, keycode, 1);
1694 		input_sync(input);
1695 		input_report_key(input, keycode, 0);
1696 		input_sync(input);
1697 	}
1698 }
1699 
1700 static int acpi_video_resume(struct notifier_block *nb,
1701 				unsigned long val, void *ign)
1702 {
1703 	struct acpi_video_bus *video;
1704 	struct acpi_video_device *video_device;
1705 	int i;
1706 
1707 	switch (val) {
1708 	case PM_POST_HIBERNATION:
1709 	case PM_POST_SUSPEND:
1710 	case PM_POST_RESTORE:
1711 		video = container_of(nb, struct acpi_video_bus, pm_nb);
1712 
1713 		dev_info(&video->device->dev, "Restoring backlight state\n");
1714 
1715 		for (i = 0; i < video->attached_count; i++) {
1716 			video_device = video->attached_array[i].bind_info;
1717 			if (video_device && video_device->brightness)
1718 				acpi_video_device_lcd_set_level(video_device,
1719 						video_device->brightness->curr);
1720 		}
1721 
1722 		return NOTIFY_OK;
1723 	}
1724 	return NOTIFY_DONE;
1725 }
1726 
1727 static acpi_status
1728 acpi_video_bus_match(acpi_handle handle, u32 level, void *context,
1729 			void **return_value)
1730 {
1731 	struct acpi_device *device = context;
1732 	struct acpi_device *sibling;
1733 
1734 	if (handle == device->handle)
1735 		return AE_CTRL_TERMINATE;
1736 
1737 	sibling = acpi_fetch_acpi_dev(handle);
1738 	if (!sibling)
1739 		return AE_OK;
1740 
1741 	if (!strcmp(acpi_device_name(sibling), ACPI_VIDEO_BUS_NAME))
1742 			return AE_ALREADY_EXISTS;
1743 
1744 	return AE_OK;
1745 }
1746 
1747 static void acpi_video_dev_register_backlight(struct acpi_video_device *device)
1748 {
1749 	struct backlight_properties props;
1750 	struct pci_dev *pdev;
1751 	acpi_handle acpi_parent;
1752 	struct device *parent = NULL;
1753 	int result;
1754 	static int count;
1755 	char *name;
1756 
1757 	result = acpi_video_init_brightness(device);
1758 	if (result)
1759 		return;
1760 
1761 	if (disable_backlight_sysfs_if > 0)
1762 		return;
1763 
1764 	name = kasprintf(GFP_KERNEL, "acpi_video%d", count);
1765 	if (!name)
1766 		return;
1767 	count++;
1768 
1769 	acpi_get_parent(device->dev->handle, &acpi_parent);
1770 
1771 	pdev = acpi_get_pci_dev(acpi_parent);
1772 	if (pdev) {
1773 		parent = &pdev->dev;
1774 		pci_dev_put(pdev);
1775 	}
1776 
1777 	memset(&props, 0, sizeof(struct backlight_properties));
1778 	props.type = BACKLIGHT_FIRMWARE;
1779 	props.max_brightness =
1780 		device->brightness->count - ACPI_VIDEO_FIRST_LEVEL - 1;
1781 	device->backlight = backlight_device_register(name,
1782 						      parent,
1783 						      device,
1784 						      &acpi_backlight_ops,
1785 						      &props);
1786 	kfree(name);
1787 	if (IS_ERR(device->backlight)) {
1788 		device->backlight = NULL;
1789 		return;
1790 	}
1791 
1792 	/*
1793 	 * Save current brightness level in case we have to restore it
1794 	 * before acpi_video_device_lcd_set_level() is called next time.
1795 	 */
1796 	device->backlight->props.brightness =
1797 			acpi_video_get_brightness(device->backlight);
1798 
1799 	device->cooling_dev = thermal_cooling_device_register("LCD",
1800 				device->dev, &video_cooling_ops);
1801 	if (IS_ERR(device->cooling_dev)) {
1802 		/*
1803 		 * Set cooling_dev to NULL so we don't crash trying to free it.
1804 		 * Also, why the hell we are returning early and not attempt to
1805 		 * register video output if cooling device registration failed?
1806 		 * -- dtor
1807 		 */
1808 		device->cooling_dev = NULL;
1809 		return;
1810 	}
1811 
1812 	dev_info(&device->dev->dev, "registered as cooling_device%d\n",
1813 		 device->cooling_dev->id);
1814 	result = sysfs_create_link(&device->dev->dev.kobj,
1815 			&device->cooling_dev->device.kobj,
1816 			"thermal_cooling");
1817 	if (result)
1818 		pr_info("sysfs link creation failed\n");
1819 
1820 	result = sysfs_create_link(&device->cooling_dev->device.kobj,
1821 			&device->dev->dev.kobj, "device");
1822 	if (result)
1823 		pr_info("Reverse sysfs link creation failed\n");
1824 }
1825 
1826 static void acpi_video_run_bcl_for_osi(struct acpi_video_bus *video)
1827 {
1828 	struct acpi_video_device *dev;
1829 	union acpi_object *levels;
1830 
1831 	mutex_lock(&video->device_list_lock);
1832 	list_for_each_entry(dev, &video->video_device_list, entry) {
1833 		if (!acpi_video_device_lcd_query_levels(dev->dev->handle, &levels))
1834 			kfree(levels);
1835 	}
1836 	mutex_unlock(&video->device_list_lock);
1837 }
1838 
1839 static bool acpi_video_should_register_backlight(struct acpi_video_device *dev)
1840 {
1841 	/*
1842 	 * Do not create backlight device for video output
1843 	 * device that is not in the enumerated list.
1844 	 */
1845 	if (!acpi_video_device_in_dod(dev)) {
1846 		dev_dbg(&dev->dev->dev, "not in _DOD list, ignore\n");
1847 		return false;
1848 	}
1849 
1850 	if (only_lcd)
1851 		return dev->flags.lcd;
1852 	return true;
1853 }
1854 
1855 static int acpi_video_bus_register_backlight(struct acpi_video_bus *video)
1856 {
1857 	struct acpi_video_device *dev;
1858 
1859 	if (video->backlight_registered)
1860 		return 0;
1861 
1862 	acpi_video_run_bcl_for_osi(video);
1863 
1864 	if (acpi_video_get_backlight_type() != acpi_backlight_video)
1865 		return 0;
1866 
1867 	mutex_lock(&video->device_list_lock);
1868 	list_for_each_entry(dev, &video->video_device_list, entry) {
1869 		if (acpi_video_should_register_backlight(dev))
1870 			acpi_video_dev_register_backlight(dev);
1871 	}
1872 	mutex_unlock(&video->device_list_lock);
1873 
1874 	video->backlight_registered = true;
1875 
1876 	video->pm_nb.notifier_call = acpi_video_resume;
1877 	video->pm_nb.priority = 0;
1878 	return register_pm_notifier(&video->pm_nb);
1879 }
1880 
1881 static void acpi_video_dev_unregister_backlight(struct acpi_video_device *device)
1882 {
1883 	if (device->backlight) {
1884 		backlight_device_unregister(device->backlight);
1885 		device->backlight = NULL;
1886 	}
1887 	if (device->brightness) {
1888 		kfree(device->brightness->levels);
1889 		kfree(device->brightness);
1890 		device->brightness = NULL;
1891 	}
1892 	if (device->cooling_dev) {
1893 		sysfs_remove_link(&device->dev->dev.kobj, "thermal_cooling");
1894 		sysfs_remove_link(&device->cooling_dev->device.kobj, "device");
1895 		thermal_cooling_device_unregister(device->cooling_dev);
1896 		device->cooling_dev = NULL;
1897 	}
1898 }
1899 
1900 static int acpi_video_bus_unregister_backlight(struct acpi_video_bus *video)
1901 {
1902 	struct acpi_video_device *dev;
1903 	int error;
1904 
1905 	if (!video->backlight_registered)
1906 		return 0;
1907 
1908 	error = unregister_pm_notifier(&video->pm_nb);
1909 
1910 	mutex_lock(&video->device_list_lock);
1911 	list_for_each_entry(dev, &video->video_device_list, entry)
1912 		acpi_video_dev_unregister_backlight(dev);
1913 	mutex_unlock(&video->device_list_lock);
1914 
1915 	video->backlight_registered = false;
1916 
1917 	return error;
1918 }
1919 
1920 static void acpi_video_dev_add_notify_handler(struct acpi_video_device *device)
1921 {
1922 	acpi_status status;
1923 	struct acpi_device *adev = device->dev;
1924 
1925 	status = acpi_install_notify_handler(adev->handle, ACPI_DEVICE_NOTIFY,
1926 					     acpi_video_device_notify, device);
1927 	if (ACPI_FAILURE(status))
1928 		dev_err(&adev->dev, "Error installing notify handler\n");
1929 	else
1930 		device->flags.notify = 1;
1931 }
1932 
1933 static int acpi_video_bus_add_notify_handler(struct acpi_video_bus *video)
1934 {
1935 	struct input_dev *input;
1936 	struct acpi_video_device *dev;
1937 	int error;
1938 
1939 	video->input = input = input_allocate_device();
1940 	if (!input) {
1941 		error = -ENOMEM;
1942 		goto out;
1943 	}
1944 
1945 	error = acpi_video_bus_start_devices(video);
1946 	if (error)
1947 		goto err_free_input;
1948 
1949 	snprintf(video->phys, sizeof(video->phys),
1950 			"%s/video/input0", acpi_device_hid(video->device));
1951 
1952 	input->name = acpi_device_name(video->device);
1953 	input->phys = video->phys;
1954 	input->id.bustype = BUS_HOST;
1955 	input->id.product = 0x06;
1956 	input->dev.parent = &video->device->dev;
1957 	input->evbit[0] = BIT(EV_KEY);
1958 	set_bit(KEY_SWITCHVIDEOMODE, input->keybit);
1959 	set_bit(KEY_VIDEO_NEXT, input->keybit);
1960 	set_bit(KEY_VIDEO_PREV, input->keybit);
1961 	set_bit(KEY_BRIGHTNESS_CYCLE, input->keybit);
1962 	set_bit(KEY_BRIGHTNESSUP, input->keybit);
1963 	set_bit(KEY_BRIGHTNESSDOWN, input->keybit);
1964 	set_bit(KEY_BRIGHTNESS_ZERO, input->keybit);
1965 	set_bit(KEY_DISPLAY_OFF, input->keybit);
1966 
1967 	error = input_register_device(input);
1968 	if (error)
1969 		goto err_stop_dev;
1970 
1971 	mutex_lock(&video->device_list_lock);
1972 	list_for_each_entry(dev, &video->video_device_list, entry)
1973 		acpi_video_dev_add_notify_handler(dev);
1974 	mutex_unlock(&video->device_list_lock);
1975 
1976 	return 0;
1977 
1978 err_stop_dev:
1979 	acpi_video_bus_stop_devices(video);
1980 err_free_input:
1981 	input_free_device(input);
1982 	video->input = NULL;
1983 out:
1984 	return error;
1985 }
1986 
1987 static void acpi_video_dev_remove_notify_handler(struct acpi_video_device *dev)
1988 {
1989 	if (dev->flags.notify) {
1990 		acpi_remove_notify_handler(dev->dev->handle, ACPI_DEVICE_NOTIFY,
1991 					   acpi_video_device_notify);
1992 		dev->flags.notify = 0;
1993 	}
1994 }
1995 
1996 static void acpi_video_bus_remove_notify_handler(struct acpi_video_bus *video)
1997 {
1998 	struct acpi_video_device *dev;
1999 
2000 	mutex_lock(&video->device_list_lock);
2001 	list_for_each_entry(dev, &video->video_device_list, entry)
2002 		acpi_video_dev_remove_notify_handler(dev);
2003 	mutex_unlock(&video->device_list_lock);
2004 
2005 	acpi_video_bus_stop_devices(video);
2006 	input_unregister_device(video->input);
2007 	video->input = NULL;
2008 }
2009 
2010 static int acpi_video_bus_put_devices(struct acpi_video_bus *video)
2011 {
2012 	struct acpi_video_device *dev, *next;
2013 
2014 	mutex_lock(&video->device_list_lock);
2015 	list_for_each_entry_safe(dev, next, &video->video_device_list, entry) {
2016 		list_del(&dev->entry);
2017 		kfree(dev);
2018 	}
2019 	mutex_unlock(&video->device_list_lock);
2020 
2021 	return 0;
2022 }
2023 
2024 static int instance;
2025 
2026 static int acpi_video_bus_add(struct acpi_device *device)
2027 {
2028 	struct acpi_video_bus *video;
2029 	int error;
2030 	acpi_status status;
2031 
2032 	status = acpi_walk_namespace(ACPI_TYPE_DEVICE,
2033 				device->parent->handle, 1,
2034 				acpi_video_bus_match, NULL,
2035 				device, NULL);
2036 	if (status == AE_ALREADY_EXISTS) {
2037 		pr_info(FW_BUG
2038 			"Duplicate ACPI video bus devices for the"
2039 			" same VGA controller, please try module "
2040 			"parameter \"video.allow_duplicates=1\""
2041 			"if the current driver doesn't work.\n");
2042 		if (!allow_duplicates)
2043 			return -ENODEV;
2044 	}
2045 
2046 	video = kzalloc(sizeof(struct acpi_video_bus), GFP_KERNEL);
2047 	if (!video)
2048 		return -ENOMEM;
2049 
2050 	/* a hack to fix the duplicate name "VID" problem on T61 */
2051 	if (!strcmp(device->pnp.bus_id, "VID")) {
2052 		if (instance)
2053 			device->pnp.bus_id[3] = '0' + instance;
2054 		instance++;
2055 	}
2056 	/* a hack to fix the duplicate name "VGA" problem on Pa 3553 */
2057 	if (!strcmp(device->pnp.bus_id, "VGA")) {
2058 		if (instance)
2059 			device->pnp.bus_id[3] = '0' + instance;
2060 		instance++;
2061 	}
2062 
2063 	video->device = device;
2064 	strcpy(acpi_device_name(device), ACPI_VIDEO_BUS_NAME);
2065 	strcpy(acpi_device_class(device), ACPI_VIDEO_CLASS);
2066 	device->driver_data = video;
2067 
2068 	acpi_video_bus_find_cap(video);
2069 	error = acpi_video_bus_check(video);
2070 	if (error)
2071 		goto err_free_video;
2072 
2073 	mutex_init(&video->device_list_lock);
2074 	INIT_LIST_HEAD(&video->video_device_list);
2075 
2076 	error = acpi_video_bus_get_devices(video, device);
2077 	if (error)
2078 		goto err_put_video;
2079 
2080 	pr_info("%s [%s] (multi-head: %s  rom: %s  post: %s)\n",
2081 	       ACPI_VIDEO_DEVICE_NAME, acpi_device_bid(device),
2082 	       video->flags.multihead ? "yes" : "no",
2083 	       video->flags.rom ? "yes" : "no",
2084 	       video->flags.post ? "yes" : "no");
2085 	mutex_lock(&video_list_lock);
2086 	list_add_tail(&video->entry, &video_bus_head);
2087 	mutex_unlock(&video_list_lock);
2088 
2089 	acpi_video_bus_register_backlight(video);
2090 	acpi_video_bus_add_notify_handler(video);
2091 
2092 	return 0;
2093 
2094 err_put_video:
2095 	acpi_video_bus_put_devices(video);
2096 	kfree(video->attached_array);
2097 err_free_video:
2098 	kfree(video);
2099 	device->driver_data = NULL;
2100 
2101 	return error;
2102 }
2103 
2104 static int acpi_video_bus_remove(struct acpi_device *device)
2105 {
2106 	struct acpi_video_bus *video = NULL;
2107 
2108 
2109 	if (!device || !acpi_driver_data(device))
2110 		return -EINVAL;
2111 
2112 	video = acpi_driver_data(device);
2113 
2114 	acpi_video_bus_remove_notify_handler(video);
2115 	acpi_video_bus_unregister_backlight(video);
2116 	acpi_video_bus_put_devices(video);
2117 
2118 	mutex_lock(&video_list_lock);
2119 	list_del(&video->entry);
2120 	mutex_unlock(&video_list_lock);
2121 
2122 	kfree(video->attached_array);
2123 	kfree(video);
2124 
2125 	return 0;
2126 }
2127 
2128 static int __init is_i740(struct pci_dev *dev)
2129 {
2130 	if (dev->device == 0x00D1)
2131 		return 1;
2132 	if (dev->device == 0x7000)
2133 		return 1;
2134 	return 0;
2135 }
2136 
2137 static int __init intel_opregion_present(void)
2138 {
2139 	int opregion = 0;
2140 	struct pci_dev *dev = NULL;
2141 	u32 address;
2142 
2143 	for_each_pci_dev(dev) {
2144 		if ((dev->class >> 8) != PCI_CLASS_DISPLAY_VGA)
2145 			continue;
2146 		if (dev->vendor != PCI_VENDOR_ID_INTEL)
2147 			continue;
2148 		/* We don't want to poke around undefined i740 registers */
2149 		if (is_i740(dev))
2150 			continue;
2151 		pci_read_config_dword(dev, 0xfc, &address);
2152 		if (!address)
2153 			continue;
2154 		opregion = 1;
2155 	}
2156 	return opregion;
2157 }
2158 
2159 /* Check if the chassis-type indicates there is no builtin LCD panel */
2160 static bool dmi_is_desktop(void)
2161 {
2162 	const char *chassis_type;
2163 	unsigned long type;
2164 
2165 	chassis_type = dmi_get_system_info(DMI_CHASSIS_TYPE);
2166 	if (!chassis_type)
2167 		return false;
2168 
2169 	if (kstrtoul(chassis_type, 10, &type) != 0)
2170 		return false;
2171 
2172 	switch (type) {
2173 	case 0x03: /* Desktop */
2174 	case 0x04: /* Low Profile Desktop */
2175 	case 0x05: /* Pizza Box */
2176 	case 0x06: /* Mini Tower */
2177 	case 0x07: /* Tower */
2178 	case 0x10: /* Lunch Box */
2179 	case 0x11: /* Main Server Chassis */
2180 		return true;
2181 	}
2182 
2183 	return false;
2184 }
2185 
2186 /*
2187  * We're seeing a lot of bogus backlight interfaces on newer machines
2188  * without a LCD such as desktops, servers and HDMI sticks. Checking the
2189  * lcd flag fixes this, enable this by default on any machines which are:
2190  * 1.  Win8 ready (where we also prefer the native backlight driver, so
2191  *     normally the acpi_video code should not register there anyways); *and*
2192  * 2.1 Report a desktop/server DMI chassis-type, or
2193  * 2.2 Are an ACPI-reduced-hardware platform (and thus won't use the EC for
2194        backlight control)
2195  */
2196 static bool should_check_lcd_flag(void)
2197 {
2198 	if (!acpi_osi_is_win8())
2199 		return false;
2200 
2201 	if (dmi_is_desktop())
2202 		return true;
2203 
2204 	if (acpi_reduced_hardware())
2205 		return true;
2206 
2207 	return false;
2208 }
2209 
2210 int acpi_video_register(void)
2211 {
2212 	int ret = 0;
2213 
2214 	mutex_lock(&register_count_mutex);
2215 	if (register_count) {
2216 		/*
2217 		 * if the function of acpi_video_register is already called,
2218 		 * don't register the acpi_video_bus again and return no error.
2219 		 */
2220 		goto leave;
2221 	}
2222 
2223 	if (only_lcd == -1)
2224 		only_lcd = should_check_lcd_flag();
2225 
2226 	dmi_check_system(video_dmi_table);
2227 
2228 	ret = acpi_bus_register_driver(&acpi_video_bus);
2229 	if (ret)
2230 		goto leave;
2231 
2232 	/*
2233 	 * When the acpi_video_bus is loaded successfully, increase
2234 	 * the counter reference.
2235 	 */
2236 	register_count = 1;
2237 
2238 leave:
2239 	mutex_unlock(&register_count_mutex);
2240 	return ret;
2241 }
2242 EXPORT_SYMBOL(acpi_video_register);
2243 
2244 void acpi_video_unregister(void)
2245 {
2246 	mutex_lock(&register_count_mutex);
2247 	if (register_count) {
2248 		acpi_bus_unregister_driver(&acpi_video_bus);
2249 		register_count = 0;
2250 		may_report_brightness_keys = false;
2251 	}
2252 	mutex_unlock(&register_count_mutex);
2253 }
2254 EXPORT_SYMBOL(acpi_video_unregister);
2255 
2256 void acpi_video_unregister_backlight(void)
2257 {
2258 	struct acpi_video_bus *video;
2259 
2260 	mutex_lock(&register_count_mutex);
2261 	if (register_count) {
2262 		mutex_lock(&video_list_lock);
2263 		list_for_each_entry(video, &video_bus_head, entry)
2264 			acpi_video_bus_unregister_backlight(video);
2265 		mutex_unlock(&video_list_lock);
2266 	}
2267 	mutex_unlock(&register_count_mutex);
2268 }
2269 
2270 bool acpi_video_handles_brightness_key_presses(void)
2271 {
2272 	return may_report_brightness_keys &&
2273 	       (report_key_events & REPORT_BRIGHTNESS_KEY_EVENTS);
2274 }
2275 EXPORT_SYMBOL(acpi_video_handles_brightness_key_presses);
2276 
2277 /*
2278  * This is kind of nasty. Hardware using Intel chipsets may require
2279  * the video opregion code to be run first in order to initialise
2280  * state before any ACPI video calls are made. To handle this we defer
2281  * registration of the video class until the opregion code has run.
2282  */
2283 
2284 static int __init acpi_video_init(void)
2285 {
2286 	/*
2287 	 * Let the module load even if ACPI is disabled (e.g. due to
2288 	 * a broken BIOS) so that i915.ko can still be loaded on such
2289 	 * old systems without an AcpiOpRegion.
2290 	 *
2291 	 * acpi_video_register() will report -ENODEV later as well due
2292 	 * to acpi_disabled when i915.ko tries to register itself afterwards.
2293 	 */
2294 	if (acpi_disabled)
2295 		return 0;
2296 
2297 	if (intel_opregion_present())
2298 		return 0;
2299 
2300 	return acpi_video_register();
2301 }
2302 
2303 static void __exit acpi_video_exit(void)
2304 {
2305 	acpi_video_detect_exit();
2306 	acpi_video_unregister();
2307 }
2308 
2309 module_init(acpi_video_init);
2310 module_exit(acpi_video_exit);
2311