xref: /openbmc/linux/drivers/acpi/acpi_video.c (revision 3e30a927)
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 #include <linux/kernel.h>
11 #include <linux/module.h>
12 #include <linux/init.h>
13 #include <linux/types.h>
14 #include <linux/list.h>
15 #include <linux/mutex.h>
16 #include <linux/input.h>
17 #include <linux/backlight.h>
18 #include <linux/thermal.h>
19 #include <linux/sort.h>
20 #include <linux/pci.h>
21 #include <linux/pci_ids.h>
22 #include <linux/slab.h>
23 #include <linux/dmi.h>
24 #include <linux/suspend.h>
25 #include <linux/acpi.h>
26 #include <acpi/video.h>
27 #include <linux/uaccess.h>
28 
29 #define PREFIX "ACPI: "
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 #define _COMPONENT		ACPI_VIDEO_COMPONENT
37 ACPI_MODULE_NAME("video");
38 
39 MODULE_AUTHOR("Bruno Ducrot");
40 MODULE_DESCRIPTION("ACPI Video Driver");
41 MODULE_LICENSE("GPL");
42 
43 static bool brightness_switch_enabled = true;
44 module_param(brightness_switch_enabled, bool, 0644);
45 
46 /*
47  * By default, we don't allow duplicate ACPI video bus devices
48  * under the same VGA controller
49  */
50 static bool allow_duplicates;
51 module_param(allow_duplicates, bool, 0644);
52 
53 static int disable_backlight_sysfs_if = -1;
54 module_param(disable_backlight_sysfs_if, int, 0444);
55 
56 #define REPORT_OUTPUT_KEY_EVENTS		0x01
57 #define REPORT_BRIGHTNESS_KEY_EVENTS		0x02
58 static int report_key_events = -1;
59 module_param(report_key_events, int, 0644);
60 MODULE_PARM_DESC(report_key_events,
61 	"0: none, 1: output changes, 2: brightness changes, 3: all");
62 
63 static int hw_changes_brightness = -1;
64 module_param(hw_changes_brightness, int, 0644);
65 MODULE_PARM_DESC(hw_changes_brightness,
66 	"Set this to 1 on buggy hw which changes the brightness itself when "
67 	"a hotkey is pressed: -1: auto, 0: normal 1: hw-changes-brightness");
68 
69 /*
70  * Whether the struct acpi_video_device_attrib::device_id_scheme bit should be
71  * assumed even if not actually set.
72  */
73 static bool device_id_scheme = false;
74 module_param(device_id_scheme, bool, 0444);
75 
76 static int only_lcd = -1;
77 module_param(only_lcd, int, 0444);
78 
79 static int register_count;
80 static DEFINE_MUTEX(register_count_mutex);
81 static DEFINE_MUTEX(video_list_lock);
82 static LIST_HEAD(video_bus_head);
83 static int acpi_video_bus_add(struct acpi_device *device);
84 static int acpi_video_bus_remove(struct acpi_device *device);
85 static void acpi_video_bus_notify(struct acpi_device *device, u32 event);
86 void acpi_video_detect_exit(void);
87 
88 /*
89  * Indices in the _BCL method response: the first two items are special,
90  * the rest are all supported levels.
91  *
92  * See page 575 of the ACPI spec 3.0
93  */
94 enum acpi_video_level_idx {
95 	ACPI_VIDEO_AC_LEVEL,		/* level when machine has full power */
96 	ACPI_VIDEO_BATTERY_LEVEL,	/* level when machine is on batteries */
97 	ACPI_VIDEO_FIRST_LEVEL,		/* actual supported levels begin here */
98 };
99 
100 static const struct acpi_device_id video_device_ids[] = {
101 	{ACPI_VIDEO_HID, 0},
102 	{"", 0},
103 };
104 MODULE_DEVICE_TABLE(acpi, video_device_ids);
105 
106 static struct acpi_driver acpi_video_bus = {
107 	.name = "video",
108 	.class = ACPI_VIDEO_CLASS,
109 	.ids = video_device_ids,
110 	.ops = {
111 		.add = acpi_video_bus_add,
112 		.remove = acpi_video_bus_remove,
113 		.notify = acpi_video_bus_notify,
114 		},
115 };
116 
117 struct acpi_video_bus_flags {
118 	u8 multihead:1;		/* can switch video heads */
119 	u8 rom:1;		/* can retrieve a video rom */
120 	u8 post:1;		/* can configure the head to */
121 	u8 reserved:5;
122 };
123 
124 struct acpi_video_bus_cap {
125 	u8 _DOS:1;		/* Enable/Disable output switching */
126 	u8 _DOD:1;		/* Enumerate all devices attached to display adapter */
127 	u8 _ROM:1;		/* Get ROM Data */
128 	u8 _GPD:1;		/* Get POST Device */
129 	u8 _SPD:1;		/* Set POST Device */
130 	u8 _VPO:1;		/* Video POST Options */
131 	u8 reserved:2;
132 };
133 
134 struct acpi_video_device_attrib {
135 	u32 display_index:4;	/* A zero-based instance of the Display */
136 	u32 display_port_attachment:4;	/* This field differentiates the display type */
137 	u32 display_type:4;	/* Describe the specific type in use */
138 	u32 vendor_specific:4;	/* Chipset Vendor Specific */
139 	u32 bios_can_detect:1;	/* BIOS can detect the device */
140 	u32 depend_on_vga:1;	/* Non-VGA output device whose power is related to
141 				   the VGA device. */
142 	u32 pipe_id:3;		/* For VGA multiple-head devices. */
143 	u32 reserved:10;	/* Must be 0 */
144 
145 	/*
146 	 * The device ID might not actually follow the scheme described by this
147 	 * struct acpi_video_device_attrib. If it does, then this bit
148 	 * device_id_scheme is set; otherwise, other fields should be ignored.
149 	 *
150 	 * (but also see the global flag device_id_scheme)
151 	 */
152 	u32 device_id_scheme:1;
153 };
154 
155 struct acpi_video_enumerated_device {
156 	union {
157 		u32 int_val;
158 		struct acpi_video_device_attrib attrib;
159 	} value;
160 	struct acpi_video_device *bind_info;
161 };
162 
163 struct acpi_video_bus {
164 	struct acpi_device *device;
165 	bool backlight_registered;
166 	u8 dos_setting;
167 	struct acpi_video_enumerated_device *attached_array;
168 	u8 attached_count;
169 	u8 child_count;
170 	struct acpi_video_bus_cap cap;
171 	struct acpi_video_bus_flags flags;
172 	struct list_head video_device_list;
173 	struct mutex device_list_lock;	/* protects video_device_list */
174 	struct list_head entry;
175 	struct input_dev *input;
176 	char phys[32];	/* for input device */
177 	struct notifier_block pm_nb;
178 };
179 
180 struct acpi_video_device_flags {
181 	u8 crt:1;
182 	u8 lcd:1;
183 	u8 tvout:1;
184 	u8 dvi:1;
185 	u8 bios:1;
186 	u8 unknown:1;
187 	u8 notify:1;
188 	u8 reserved:1;
189 };
190 
191 struct acpi_video_device_cap {
192 	u8 _ADR:1;		/* Return the unique ID */
193 	u8 _BCL:1;		/* Query list of brightness control levels supported */
194 	u8 _BCM:1;		/* Set the brightness level */
195 	u8 _BQC:1;		/* Get current brightness level */
196 	u8 _BCQ:1;		/* Some buggy BIOS uses _BCQ instead of _BQC */
197 	u8 _DDC:1;		/* Return the EDID for this device */
198 };
199 
200 struct acpi_video_device {
201 	unsigned long device_id;
202 	struct acpi_video_device_flags flags;
203 	struct acpi_video_device_cap cap;
204 	struct list_head entry;
205 	struct delayed_work switch_brightness_work;
206 	int switch_brightness_event;
207 	struct acpi_video_bus *video;
208 	struct acpi_device *dev;
209 	struct acpi_video_device_brightness *brightness;
210 	struct backlight_device *backlight;
211 	struct thermal_cooling_device *cooling_dev;
212 };
213 
214 static void acpi_video_device_notify(acpi_handle handle, u32 event, void *data);
215 static void acpi_video_device_rebind(struct acpi_video_bus *video);
216 static void acpi_video_device_bind(struct acpi_video_bus *video,
217 				   struct acpi_video_device *device);
218 static int acpi_video_device_enumerate(struct acpi_video_bus *video);
219 static int acpi_video_device_lcd_set_level(struct acpi_video_device *device,
220 			int level);
221 static int acpi_video_device_lcd_get_level_current(
222 			struct acpi_video_device *device,
223 			unsigned long long *level, bool raw);
224 static int acpi_video_get_next_level(struct acpi_video_device *device,
225 				     u32 level_current, u32 event);
226 static void acpi_video_switch_brightness(struct work_struct *work);
227 
228 /* backlight device sysfs support */
229 static int acpi_video_get_brightness(struct backlight_device *bd)
230 {
231 	unsigned long long cur_level;
232 	int i;
233 	struct acpi_video_device *vd = bl_get_data(bd);
234 
235 	if (acpi_video_device_lcd_get_level_current(vd, &cur_level, false))
236 		return -EINVAL;
237 	for (i = ACPI_VIDEO_FIRST_LEVEL; i < vd->brightness->count; i++) {
238 		if (vd->brightness->levels[i] == cur_level)
239 			return i - ACPI_VIDEO_FIRST_LEVEL;
240 	}
241 	return 0;
242 }
243 
244 static int acpi_video_set_brightness(struct backlight_device *bd)
245 {
246 	int request_level = bd->props.brightness + ACPI_VIDEO_FIRST_LEVEL;
247 	struct acpi_video_device *vd = bl_get_data(bd);
248 
249 	cancel_delayed_work(&vd->switch_brightness_work);
250 	return acpi_video_device_lcd_set_level(vd,
251 				vd->brightness->levels[request_level]);
252 }
253 
254 static const struct backlight_ops acpi_backlight_ops = {
255 	.get_brightness = acpi_video_get_brightness,
256 	.update_status  = acpi_video_set_brightness,
257 };
258 
259 /* thermal cooling device callbacks */
260 static int video_get_max_state(struct thermal_cooling_device *cooling_dev,
261 			       unsigned long *state)
262 {
263 	struct acpi_device *device = cooling_dev->devdata;
264 	struct acpi_video_device *video = acpi_driver_data(device);
265 
266 	*state = video->brightness->count - ACPI_VIDEO_FIRST_LEVEL - 1;
267 	return 0;
268 }
269 
270 static int video_get_cur_state(struct thermal_cooling_device *cooling_dev,
271 			       unsigned long *state)
272 {
273 	struct acpi_device *device = cooling_dev->devdata;
274 	struct acpi_video_device *video = acpi_driver_data(device);
275 	unsigned long long level;
276 	int offset;
277 
278 	if (acpi_video_device_lcd_get_level_current(video, &level, false))
279 		return -EINVAL;
280 	for (offset = ACPI_VIDEO_FIRST_LEVEL; offset < video->brightness->count;
281 	     offset++)
282 		if (level == video->brightness->levels[offset]) {
283 			*state = video->brightness->count - offset - 1;
284 			return 0;
285 		}
286 
287 	return -EINVAL;
288 }
289 
290 static int
291 video_set_cur_state(struct thermal_cooling_device *cooling_dev, unsigned long state)
292 {
293 	struct acpi_device *device = cooling_dev->devdata;
294 	struct acpi_video_device *video = acpi_driver_data(device);
295 	int level;
296 
297 	if (state >= video->brightness->count - ACPI_VIDEO_FIRST_LEVEL)
298 		return -EINVAL;
299 
300 	state = video->brightness->count - state;
301 	level = video->brightness->levels[state - 1];
302 	return acpi_video_device_lcd_set_level(video, level);
303 }
304 
305 static const struct thermal_cooling_device_ops video_cooling_ops = {
306 	.get_max_state = video_get_max_state,
307 	.get_cur_state = video_get_cur_state,
308 	.set_cur_state = video_set_cur_state,
309 };
310 
311 /*
312  * --------------------------------------------------------------------------
313  *                             Video Management
314  * --------------------------------------------------------------------------
315  */
316 
317 static int
318 acpi_video_device_lcd_query_levels(acpi_handle handle,
319 				   union acpi_object **levels)
320 {
321 	int status;
322 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
323 	union acpi_object *obj;
324 
325 
326 	*levels = NULL;
327 
328 	status = acpi_evaluate_object(handle, "_BCL", NULL, &buffer);
329 	if (!ACPI_SUCCESS(status))
330 		return status;
331 	obj = (union acpi_object *)buffer.pointer;
332 	if (!obj || (obj->type != ACPI_TYPE_PACKAGE)) {
333 		printk(KERN_ERR PREFIX "Invalid _BCL data\n");
334 		status = -EFAULT;
335 		goto err;
336 	}
337 
338 	*levels = obj;
339 
340 	return 0;
341 
342 err:
343 	kfree(buffer.pointer);
344 
345 	return status;
346 }
347 
348 static int
349 acpi_video_device_lcd_set_level(struct acpi_video_device *device, int level)
350 {
351 	int status;
352 	int state;
353 
354 	status = acpi_execute_simple_method(device->dev->handle,
355 					    "_BCM", level);
356 	if (ACPI_FAILURE(status)) {
357 		ACPI_ERROR((AE_INFO, "Evaluating _BCM failed"));
358 		return -EIO;
359 	}
360 
361 	device->brightness->curr = level;
362 	for (state = ACPI_VIDEO_FIRST_LEVEL; state < device->brightness->count;
363 	     state++)
364 		if (level == device->brightness->levels[state]) {
365 			if (device->backlight)
366 				device->backlight->props.brightness =
367 					state - ACPI_VIDEO_FIRST_LEVEL;
368 			return 0;
369 		}
370 
371 	ACPI_ERROR((AE_INFO, "Current brightness invalid"));
372 	return -EINVAL;
373 }
374 
375 /*
376  * For some buggy _BQC methods, we need to add a constant value to
377  * the _BQC return value to get the actual current brightness level
378  */
379 
380 static int bqc_offset_aml_bug_workaround;
381 static int video_set_bqc_offset(const struct dmi_system_id *d)
382 {
383 	bqc_offset_aml_bug_workaround = 9;
384 	return 0;
385 }
386 
387 static int video_disable_backlight_sysfs_if(
388 	const struct dmi_system_id *d)
389 {
390 	if (disable_backlight_sysfs_if == -1)
391 		disable_backlight_sysfs_if = 1;
392 	return 0;
393 }
394 
395 static int video_set_device_id_scheme(const struct dmi_system_id *d)
396 {
397 	device_id_scheme = true;
398 	return 0;
399 }
400 
401 static int video_enable_only_lcd(const struct dmi_system_id *d)
402 {
403 	only_lcd = true;
404 	return 0;
405 }
406 
407 static int video_set_report_key_events(const struct dmi_system_id *id)
408 {
409 	if (report_key_events == -1)
410 		report_key_events = (uintptr_t)id->driver_data;
411 	return 0;
412 }
413 
414 static int video_hw_changes_brightness(
415 	const struct dmi_system_id *d)
416 {
417 	if (hw_changes_brightness == -1)
418 		hw_changes_brightness = 1;
419 	return 0;
420 }
421 
422 static const struct dmi_system_id video_dmi_table[] = {
423 	/*
424 	 * Broken _BQC workaround http://bugzilla.kernel.org/show_bug.cgi?id=13121
425 	 */
426 	{
427 	 .callback = video_set_bqc_offset,
428 	 .ident = "Acer Aspire 5720",
429 	 .matches = {
430 		DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
431 		DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5720"),
432 		},
433 	},
434 	{
435 	 .callback = video_set_bqc_offset,
436 	 .ident = "Acer Aspire 5710Z",
437 	 .matches = {
438 		DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
439 		DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5710Z"),
440 		},
441 	},
442 	{
443 	 .callback = video_set_bqc_offset,
444 	 .ident = "eMachines E510",
445 	 .matches = {
446 		DMI_MATCH(DMI_BOARD_VENDOR, "EMACHINES"),
447 		DMI_MATCH(DMI_PRODUCT_NAME, "eMachines E510"),
448 		},
449 	},
450 	{
451 	 .callback = video_set_bqc_offset,
452 	 .ident = "Acer Aspire 5315",
453 	 .matches = {
454 		DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
455 		DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5315"),
456 		},
457 	},
458 	{
459 	 .callback = video_set_bqc_offset,
460 	 .ident = "Acer Aspire 7720",
461 	 .matches = {
462 		DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
463 		DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 7720"),
464 		},
465 	},
466 
467 	/*
468 	 * Some machines have a broken acpi-video interface for brightness
469 	 * control, but still need an acpi_video_device_lcd_set_level() call
470 	 * on resume to turn the backlight power on.  We Enable backlight
471 	 * control on these systems, but do not register a backlight sysfs
472 	 * as brightness control does not work.
473 	 */
474 	{
475 	 /* https://bugzilla.kernel.org/show_bug.cgi?id=21012 */
476 	 .callback = video_disable_backlight_sysfs_if,
477 	 .ident = "Toshiba Portege R700",
478 	 .matches = {
479 		DMI_MATCH(DMI_SYS_VENDOR, "TOSHIBA"),
480 		DMI_MATCH(DMI_PRODUCT_NAME, "PORTEGE R700"),
481 		},
482 	},
483 	{
484 	 /* https://bugs.freedesktop.org/show_bug.cgi?id=82634 */
485 	 .callback = video_disable_backlight_sysfs_if,
486 	 .ident = "Toshiba Portege R830",
487 	 .matches = {
488 		DMI_MATCH(DMI_SYS_VENDOR, "TOSHIBA"),
489 		DMI_MATCH(DMI_PRODUCT_NAME, "PORTEGE R830"),
490 		},
491 	},
492 	{
493 	 /* https://bugzilla.kernel.org/show_bug.cgi?id=21012 */
494 	 .callback = video_disable_backlight_sysfs_if,
495 	 .ident = "Toshiba Satellite R830",
496 	 .matches = {
497 		DMI_MATCH(DMI_SYS_VENDOR, "TOSHIBA"),
498 		DMI_MATCH(DMI_PRODUCT_NAME, "SATELLITE R830"),
499 		},
500 	},
501 	/*
502 	 * Some machine's _DOD IDs don't have bit 31(Device ID Scheme) set
503 	 * but the IDs actually follow the Device ID Scheme.
504 	 */
505 	{
506 	 /* https://bugzilla.kernel.org/show_bug.cgi?id=104121 */
507 	 .callback = video_set_device_id_scheme,
508 	 .ident = "ESPRIMO Mobile M9410",
509 	 .matches = {
510 		DMI_MATCH(DMI_SYS_VENDOR, "FUJITSU SIEMENS"),
511 		DMI_MATCH(DMI_PRODUCT_NAME, "ESPRIMO Mobile M9410"),
512 		},
513 	},
514 	/*
515 	 * Some machines have multiple video output devices, but only the one
516 	 * that is the type of LCD can do the backlight control so we should not
517 	 * register backlight interface for other video output devices.
518 	 */
519 	{
520 	 /* https://bugzilla.kernel.org/show_bug.cgi?id=104121 */
521 	 .callback = video_enable_only_lcd,
522 	 .ident = "ESPRIMO Mobile M9410",
523 	 .matches = {
524 		DMI_MATCH(DMI_SYS_VENDOR, "FUJITSU SIEMENS"),
525 		DMI_MATCH(DMI_PRODUCT_NAME, "ESPRIMO Mobile M9410"),
526 		},
527 	},
528 	/*
529 	 * Some machines report wrong key events on the acpi-bus, suppress
530 	 * key event reporting on these.  Note this is only intended to work
531 	 * around events which are plain wrong. In some cases we get double
532 	 * events, in this case acpi-video is considered the canonical source
533 	 * and the events from the other source should be filtered. E.g.
534 	 * by calling acpi_video_handles_brightness_key_presses() from the
535 	 * vendor acpi/wmi driver or by using /lib/udev/hwdb.d/60-keyboard.hwdb
536 	 */
537 	{
538 	 .callback = video_set_report_key_events,
539 	 .driver_data = (void *)((uintptr_t)REPORT_OUTPUT_KEY_EVENTS),
540 	 .ident = "Dell Vostro V131",
541 	 .matches = {
542 		DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
543 		DMI_MATCH(DMI_PRODUCT_NAME, "Vostro V131"),
544 		},
545 	},
546 	/*
547 	 * Some machines change the brightness themselves when a brightness
548 	 * hotkey gets pressed, despite us telling them not to. In this case
549 	 * acpi_video_device_notify() should only call backlight_force_update(
550 	 * BACKLIGHT_UPDATE_HOTKEY) and not do anything else.
551 	 */
552 	{
553 	 /* https://bugzilla.kernel.org/show_bug.cgi?id=204077 */
554 	 .callback = video_hw_changes_brightness,
555 	 .ident = "Packard Bell EasyNote MZ35",
556 	 .matches = {
557 		DMI_MATCH(DMI_SYS_VENDOR, "Packard Bell"),
558 		DMI_MATCH(DMI_PRODUCT_NAME, "EasyNote MZ35"),
559 		},
560 	},
561 	{}
562 };
563 
564 static unsigned long long
565 acpi_video_bqc_value_to_level(struct acpi_video_device *device,
566 			      unsigned long long bqc_value)
567 {
568 	unsigned long long level;
569 
570 	if (device->brightness->flags._BQC_use_index) {
571 		/*
572 		 * _BQC returns an index that doesn't account for the first 2
573 		 * items with special meaning (see enum acpi_video_level_idx),
574 		 * so we need to compensate for that by offsetting ourselves
575 		 */
576 		if (device->brightness->flags._BCL_reversed)
577 			bqc_value = device->brightness->count -
578 				ACPI_VIDEO_FIRST_LEVEL - 1 - bqc_value;
579 
580 		level = device->brightness->levels[bqc_value +
581 		                                   ACPI_VIDEO_FIRST_LEVEL];
582 	} else {
583 		level = bqc_value;
584 	}
585 
586 	level += bqc_offset_aml_bug_workaround;
587 
588 	return level;
589 }
590 
591 static int
592 acpi_video_device_lcd_get_level_current(struct acpi_video_device *device,
593 					unsigned long long *level, bool raw)
594 {
595 	acpi_status status = AE_OK;
596 	int i;
597 
598 	if (device->cap._BQC || device->cap._BCQ) {
599 		char *buf = device->cap._BQC ? "_BQC" : "_BCQ";
600 
601 		status = acpi_evaluate_integer(device->dev->handle, buf,
602 						NULL, level);
603 		if (ACPI_SUCCESS(status)) {
604 			if (raw) {
605 				/*
606 				 * Caller has indicated he wants the raw
607 				 * value returned by _BQC, so don't furtherly
608 				 * mess with the value.
609 				 */
610 				return 0;
611 			}
612 
613 			*level = acpi_video_bqc_value_to_level(device, *level);
614 
615 			for (i = ACPI_VIDEO_FIRST_LEVEL;
616 			     i < device->brightness->count; i++)
617 				if (device->brightness->levels[i] == *level) {
618 					device->brightness->curr = *level;
619 					return 0;
620 				}
621 			/*
622 			 * BQC returned an invalid level.
623 			 * Stop using it.
624 			 */
625 			ACPI_WARNING((AE_INFO,
626 				      "%s returned an invalid level",
627 				      buf));
628 			device->cap._BQC = device->cap._BCQ = 0;
629 		} else {
630 			/*
631 			 * Fixme:
632 			 * should we return an error or ignore this failure?
633 			 * dev->brightness->curr is a cached value which stores
634 			 * the correct current backlight level in most cases.
635 			 * ACPI video backlight still works w/ buggy _BQC.
636 			 * http://bugzilla.kernel.org/show_bug.cgi?id=12233
637 			 */
638 			ACPI_WARNING((AE_INFO, "Evaluating %s failed", buf));
639 			device->cap._BQC = device->cap._BCQ = 0;
640 		}
641 	}
642 
643 	*level = device->brightness->curr;
644 	return 0;
645 }
646 
647 static int
648 acpi_video_device_EDID(struct acpi_video_device *device,
649 		       union acpi_object **edid, ssize_t length)
650 {
651 	int status;
652 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
653 	union acpi_object *obj;
654 	union acpi_object arg0 = { ACPI_TYPE_INTEGER };
655 	struct acpi_object_list args = { 1, &arg0 };
656 
657 
658 	*edid = NULL;
659 
660 	if (!device)
661 		return -ENODEV;
662 	if (length == 128)
663 		arg0.integer.value = 1;
664 	else if (length == 256)
665 		arg0.integer.value = 2;
666 	else
667 		return -EINVAL;
668 
669 	status = acpi_evaluate_object(device->dev->handle, "_DDC", &args, &buffer);
670 	if (ACPI_FAILURE(status))
671 		return -ENODEV;
672 
673 	obj = buffer.pointer;
674 
675 	if (obj && obj->type == ACPI_TYPE_BUFFER)
676 		*edid = obj;
677 	else {
678 		printk(KERN_ERR PREFIX "Invalid _DDC data\n");
679 		status = -EFAULT;
680 		kfree(obj);
681 	}
682 
683 	return status;
684 }
685 
686 /* bus */
687 
688 /*
689  *  Arg:
690  *	video		: video bus device pointer
691  *	bios_flag	:
692  *		0.	The system BIOS should NOT automatically switch(toggle)
693  *			the active display output.
694  *		1.	The system BIOS should automatically switch (toggle) the
695  *			active display output. No switch event.
696  *		2.	The _DGS value should be locked.
697  *		3.	The system BIOS should not automatically switch (toggle) the
698  *			active display output, but instead generate the display switch
699  *			event notify code.
700  *	lcd_flag	:
701  *		0.	The system BIOS should automatically control the brightness level
702  *			of the LCD when:
703  *			- the power changes from AC to DC (ACPI appendix B)
704  *			- a brightness hotkey gets pressed (implied by Win7/8 backlight docs)
705  *		1.	The system BIOS should NOT automatically control the brightness
706  *			level of the LCD when:
707  *			- the power changes from AC to DC (ACPI appendix B)
708  *			- a brightness hotkey gets pressed (implied by Win7/8 backlight docs)
709  *  Return Value:
710  *		-EINVAL	wrong arg.
711  */
712 
713 static int
714 acpi_video_bus_DOS(struct acpi_video_bus *video, int bios_flag, int lcd_flag)
715 {
716 	acpi_status status;
717 
718 	if (!video->cap._DOS)
719 		return 0;
720 
721 	if (bios_flag < 0 || bios_flag > 3 || lcd_flag < 0 || lcd_flag > 1)
722 		return -EINVAL;
723 	video->dos_setting = (lcd_flag << 2) | bios_flag;
724 	status = acpi_execute_simple_method(video->device->handle, "_DOS",
725 					    (lcd_flag << 2) | bios_flag);
726 	if (ACPI_FAILURE(status))
727 		return -EIO;
728 
729 	return 0;
730 }
731 
732 /*
733  * Simple comparison function used to sort backlight levels.
734  */
735 
736 static int
737 acpi_video_cmp_level(const void *a, const void *b)
738 {
739 	return *(int *)a - *(int *)b;
740 }
741 
742 /*
743  * Decides if _BQC/_BCQ for this system is usable
744  *
745  * We do this by changing the level first and then read out the current
746  * brightness level, if the value does not match, find out if it is using
747  * index. If not, clear the _BQC/_BCQ capability.
748  */
749 static int acpi_video_bqc_quirk(struct acpi_video_device *device,
750 				int max_level, int current_level)
751 {
752 	struct acpi_video_device_brightness *br = device->brightness;
753 	int result;
754 	unsigned long long level;
755 	int test_level;
756 
757 	/* don't mess with existing known broken systems */
758 	if (bqc_offset_aml_bug_workaround)
759 		return 0;
760 
761 	/*
762 	 * Some systems always report current brightness level as maximum
763 	 * through _BQC, we need to test another value for them. However,
764 	 * there is a subtlety:
765 	 *
766 	 * If the _BCL package ordering is descending, the first level
767 	 * (br->levels[2]) is likely to be 0, and if the number of levels
768 	 * matches the number of steps, we might confuse a returned level to
769 	 * mean the index.
770 	 *
771 	 * For example:
772 	 *
773 	 *     current_level = max_level = 100
774 	 *     test_level = 0
775 	 *     returned level = 100
776 	 *
777 	 * In this case 100 means the level, not the index, and _BCM failed.
778 	 * Still, if the _BCL package ordering is descending, the index of
779 	 * level 0 is also 100, so we assume _BQC is indexed, when it's not.
780 	 *
781 	 * This causes all _BQC calls to return bogus values causing weird
782 	 * behavior from the user's perspective.  For example:
783 	 *
784 	 * xbacklight -set 10; xbacklight -set 20;
785 	 *
786 	 * would flash to 90% and then slowly down to the desired level (20).
787 	 *
788 	 * The solution is simple; test anything other than the first level
789 	 * (e.g. 1).
790 	 */
791 	test_level = current_level == max_level
792 		? br->levels[ACPI_VIDEO_FIRST_LEVEL + 1]
793 		: max_level;
794 
795 	result = acpi_video_device_lcd_set_level(device, test_level);
796 	if (result)
797 		return result;
798 
799 	result = acpi_video_device_lcd_get_level_current(device, &level, true);
800 	if (result)
801 		return result;
802 
803 	if (level != test_level) {
804 		/* buggy _BQC found, need to find out if it uses index */
805 		if (level < br->count) {
806 			if (br->flags._BCL_reversed)
807 				level = br->count - ACPI_VIDEO_FIRST_LEVEL - 1 - level;
808 			if (br->levels[level + ACPI_VIDEO_FIRST_LEVEL] == test_level)
809 				br->flags._BQC_use_index = 1;
810 		}
811 
812 		if (!br->flags._BQC_use_index)
813 			device->cap._BQC = device->cap._BCQ = 0;
814 	}
815 
816 	return 0;
817 }
818 
819 int acpi_video_get_levels(struct acpi_device *device,
820 			  struct acpi_video_device_brightness **dev_br,
821 			  int *pmax_level)
822 {
823 	union acpi_object *obj = NULL;
824 	int i, max_level = 0, count = 0, level_ac_battery = 0;
825 	union acpi_object *o;
826 	struct acpi_video_device_brightness *br = NULL;
827 	int result = 0;
828 	u32 value;
829 
830 	if (!ACPI_SUCCESS(acpi_video_device_lcd_query_levels(device->handle,
831 								&obj))) {
832 		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Could not query available "
833 						"LCD brightness level\n"));
834 		result = -ENODEV;
835 		goto out;
836 	}
837 
838 	if (obj->package.count < ACPI_VIDEO_FIRST_LEVEL) {
839 		result = -EINVAL;
840 		goto out;
841 	}
842 
843 	br = kzalloc(sizeof(*br), GFP_KERNEL);
844 	if (!br) {
845 		printk(KERN_ERR "can't allocate memory\n");
846 		result = -ENOMEM;
847 		goto out;
848 	}
849 
850 	/*
851 	 * Note that we have to reserve 2 extra items (ACPI_VIDEO_FIRST_LEVEL),
852 	 * in order to account for buggy BIOS which don't export the first two
853 	 * special levels (see below)
854 	 */
855 	br->levels = kmalloc_array(obj->package.count + ACPI_VIDEO_FIRST_LEVEL,
856 				   sizeof(*br->levels),
857 				   GFP_KERNEL);
858 	if (!br->levels) {
859 		result = -ENOMEM;
860 		goto out_free;
861 	}
862 
863 	for (i = 0; i < obj->package.count; i++) {
864 		o = (union acpi_object *)&obj->package.elements[i];
865 		if (o->type != ACPI_TYPE_INTEGER) {
866 			printk(KERN_ERR PREFIX "Invalid data\n");
867 			continue;
868 		}
869 		value = (u32) o->integer.value;
870 		/* Skip duplicate entries */
871 		if (count > ACPI_VIDEO_FIRST_LEVEL
872 		    && br->levels[count - 1] == value)
873 			continue;
874 
875 		br->levels[count] = value;
876 
877 		if (br->levels[count] > max_level)
878 			max_level = br->levels[count];
879 		count++;
880 	}
881 
882 	/*
883 	 * some buggy BIOS don't export the levels
884 	 * when machine is on AC/Battery in _BCL package.
885 	 * In this case, the first two elements in _BCL packages
886 	 * are also supported brightness levels that OS should take care of.
887 	 */
888 	for (i = ACPI_VIDEO_FIRST_LEVEL; i < count; i++) {
889 		if (br->levels[i] == br->levels[ACPI_VIDEO_AC_LEVEL])
890 			level_ac_battery++;
891 		if (br->levels[i] == br->levels[ACPI_VIDEO_BATTERY_LEVEL])
892 			level_ac_battery++;
893 	}
894 
895 	if (level_ac_battery < ACPI_VIDEO_FIRST_LEVEL) {
896 		level_ac_battery = ACPI_VIDEO_FIRST_LEVEL - level_ac_battery;
897 		br->flags._BCL_no_ac_battery_levels = 1;
898 		for (i = (count - 1 + level_ac_battery);
899 		     i >= ACPI_VIDEO_FIRST_LEVEL; i--)
900 			br->levels[i] = br->levels[i - level_ac_battery];
901 		count += level_ac_battery;
902 	} else if (level_ac_battery > ACPI_VIDEO_FIRST_LEVEL)
903 		ACPI_ERROR((AE_INFO, "Too many duplicates in _BCL package"));
904 
905 	/* Check if the _BCL package is in a reversed order */
906 	if (max_level == br->levels[ACPI_VIDEO_FIRST_LEVEL]) {
907 		br->flags._BCL_reversed = 1;
908 		sort(&br->levels[ACPI_VIDEO_FIRST_LEVEL],
909 		     count - ACPI_VIDEO_FIRST_LEVEL,
910 		     sizeof(br->levels[ACPI_VIDEO_FIRST_LEVEL]),
911 		     acpi_video_cmp_level, NULL);
912 	} else if (max_level != br->levels[count - 1])
913 		ACPI_ERROR((AE_INFO,
914 			    "Found unordered _BCL package"));
915 
916 	br->count = count;
917 	*dev_br = br;
918 	if (pmax_level)
919 		*pmax_level = max_level;
920 
921 out:
922 	kfree(obj);
923 	return result;
924 out_free:
925 	kfree(br);
926 	goto out;
927 }
928 EXPORT_SYMBOL(acpi_video_get_levels);
929 
930 /*
931  *  Arg:
932  *	device	: video output device (LCD, CRT, ..)
933  *
934  *  Return Value:
935  *	Maximum brightness level
936  *
937  *  Allocate and initialize device->brightness.
938  */
939 
940 static int
941 acpi_video_init_brightness(struct acpi_video_device *device)
942 {
943 	int i, max_level = 0;
944 	unsigned long long level, level_old;
945 	struct acpi_video_device_brightness *br = NULL;
946 	int result = -EINVAL;
947 
948 	result = acpi_video_get_levels(device->dev, &br, &max_level);
949 	if (result)
950 		return result;
951 	device->brightness = br;
952 
953 	/* _BQC uses INDEX while _BCL uses VALUE in some laptops */
954 	br->curr = level = max_level;
955 
956 	if (!device->cap._BQC)
957 		goto set_level;
958 
959 	result = acpi_video_device_lcd_get_level_current(device,
960 							 &level_old, true);
961 	if (result)
962 		goto out_free_levels;
963 
964 	result = acpi_video_bqc_quirk(device, max_level, level_old);
965 	if (result)
966 		goto out_free_levels;
967 	/*
968 	 * cap._BQC may get cleared due to _BQC is found to be broken
969 	 * in acpi_video_bqc_quirk, so check again here.
970 	 */
971 	if (!device->cap._BQC)
972 		goto set_level;
973 
974 	level = acpi_video_bqc_value_to_level(device, level_old);
975 	/*
976 	 * On some buggy laptops, _BQC returns an uninitialized
977 	 * value when invoked for the first time, i.e.
978 	 * level_old is invalid (no matter whether it's a level
979 	 * or an index). Set the backlight to max_level in this case.
980 	 */
981 	for (i = ACPI_VIDEO_FIRST_LEVEL; i < br->count; i++)
982 		if (level == br->levels[i])
983 			break;
984 	if (i == br->count || !level)
985 		level = max_level;
986 
987 set_level:
988 	result = acpi_video_device_lcd_set_level(device, level);
989 	if (result)
990 		goto out_free_levels;
991 
992 	ACPI_DEBUG_PRINT((ACPI_DB_INFO,
993 	                  "found %d brightness levels\n",
994 	                  br->count - ACPI_VIDEO_FIRST_LEVEL));
995 	return 0;
996 
997 out_free_levels:
998 	kfree(br->levels);
999 	kfree(br);
1000 	device->brightness = NULL;
1001 	return result;
1002 }
1003 
1004 /*
1005  *  Arg:
1006  *	device	: video output device (LCD, CRT, ..)
1007  *
1008  *  Return Value:
1009  *	None
1010  *
1011  *  Find out all required AML methods defined under the output
1012  *  device.
1013  */
1014 
1015 static void acpi_video_device_find_cap(struct acpi_video_device *device)
1016 {
1017 	if (acpi_has_method(device->dev->handle, "_ADR"))
1018 		device->cap._ADR = 1;
1019 	if (acpi_has_method(device->dev->handle, "_BCL"))
1020 		device->cap._BCL = 1;
1021 	if (acpi_has_method(device->dev->handle, "_BCM"))
1022 		device->cap._BCM = 1;
1023 	if (acpi_has_method(device->dev->handle, "_BQC")) {
1024 		device->cap._BQC = 1;
1025 	} else if (acpi_has_method(device->dev->handle, "_BCQ")) {
1026 		printk(KERN_WARNING FW_BUG "_BCQ is used instead of _BQC\n");
1027 		device->cap._BCQ = 1;
1028 	}
1029 
1030 	if (acpi_has_method(device->dev->handle, "_DDC"))
1031 		device->cap._DDC = 1;
1032 }
1033 
1034 /*
1035  *  Arg:
1036  *	device	: video output device (VGA)
1037  *
1038  *  Return Value:
1039  *	None
1040  *
1041  *  Find out all required AML methods defined under the video bus device.
1042  */
1043 
1044 static void acpi_video_bus_find_cap(struct acpi_video_bus *video)
1045 {
1046 	if (acpi_has_method(video->device->handle, "_DOS"))
1047 		video->cap._DOS = 1;
1048 	if (acpi_has_method(video->device->handle, "_DOD"))
1049 		video->cap._DOD = 1;
1050 	if (acpi_has_method(video->device->handle, "_ROM"))
1051 		video->cap._ROM = 1;
1052 	if (acpi_has_method(video->device->handle, "_GPD"))
1053 		video->cap._GPD = 1;
1054 	if (acpi_has_method(video->device->handle, "_SPD"))
1055 		video->cap._SPD = 1;
1056 	if (acpi_has_method(video->device->handle, "_VPO"))
1057 		video->cap._VPO = 1;
1058 }
1059 
1060 /*
1061  * Check whether the video bus device has required AML method to
1062  * support the desired features
1063  */
1064 
1065 static int acpi_video_bus_check(struct acpi_video_bus *video)
1066 {
1067 	acpi_status status = -ENOENT;
1068 	struct pci_dev *dev;
1069 
1070 	if (!video)
1071 		return -EINVAL;
1072 
1073 	dev = acpi_get_pci_dev(video->device->handle);
1074 	if (!dev)
1075 		return -ENODEV;
1076 	pci_dev_put(dev);
1077 
1078 	/*
1079 	 * Since there is no HID, CID and so on for VGA driver, we have
1080 	 * to check well known required nodes.
1081 	 */
1082 
1083 	/* Does this device support video switching? */
1084 	if (video->cap._DOS || video->cap._DOD) {
1085 		if (!video->cap._DOS) {
1086 			printk(KERN_WARNING FW_BUG
1087 				"ACPI(%s) defines _DOD but not _DOS\n",
1088 				acpi_device_bid(video->device));
1089 		}
1090 		video->flags.multihead = 1;
1091 		status = 0;
1092 	}
1093 
1094 	/* Does this device support retrieving a video ROM? */
1095 	if (video->cap._ROM) {
1096 		video->flags.rom = 1;
1097 		status = 0;
1098 	}
1099 
1100 	/* Does this device support configuring which video device to POST? */
1101 	if (video->cap._GPD && video->cap._SPD && video->cap._VPO) {
1102 		video->flags.post = 1;
1103 		status = 0;
1104 	}
1105 
1106 	return status;
1107 }
1108 
1109 /*
1110  * --------------------------------------------------------------------------
1111  *                               Driver Interface
1112  * --------------------------------------------------------------------------
1113  */
1114 
1115 /* device interface */
1116 static struct acpi_video_device_attrib *
1117 acpi_video_get_device_attr(struct acpi_video_bus *video, unsigned long device_id)
1118 {
1119 	struct acpi_video_enumerated_device *ids;
1120 	int i;
1121 
1122 	for (i = 0; i < video->attached_count; i++) {
1123 		ids = &video->attached_array[i];
1124 		if ((ids->value.int_val & 0xffff) == device_id)
1125 			return &ids->value.attrib;
1126 	}
1127 
1128 	return NULL;
1129 }
1130 
1131 static int
1132 acpi_video_get_device_type(struct acpi_video_bus *video,
1133 			   unsigned long device_id)
1134 {
1135 	struct acpi_video_enumerated_device *ids;
1136 	int i;
1137 
1138 	for (i = 0; i < video->attached_count; i++) {
1139 		ids = &video->attached_array[i];
1140 		if ((ids->value.int_val & 0xffff) == device_id)
1141 			return ids->value.int_val;
1142 	}
1143 
1144 	return 0;
1145 }
1146 
1147 static int
1148 acpi_video_bus_get_one_device(struct acpi_device *device,
1149 			      struct acpi_video_bus *video)
1150 {
1151 	unsigned long long device_id;
1152 	int status, device_type;
1153 	struct acpi_video_device *data;
1154 	struct acpi_video_device_attrib *attribute;
1155 
1156 	status =
1157 	    acpi_evaluate_integer(device->handle, "_ADR", NULL, &device_id);
1158 	/* Some device omits _ADR, we skip them instead of fail */
1159 	if (ACPI_FAILURE(status))
1160 		return 0;
1161 
1162 	data = kzalloc(sizeof(struct acpi_video_device), GFP_KERNEL);
1163 	if (!data)
1164 		return -ENOMEM;
1165 
1166 	strcpy(acpi_device_name(device), ACPI_VIDEO_DEVICE_NAME);
1167 	strcpy(acpi_device_class(device), ACPI_VIDEO_CLASS);
1168 	device->driver_data = data;
1169 
1170 	data->device_id = device_id;
1171 	data->video = video;
1172 	data->dev = device;
1173 	INIT_DELAYED_WORK(&data->switch_brightness_work,
1174 			  acpi_video_switch_brightness);
1175 
1176 	attribute = acpi_video_get_device_attr(video, device_id);
1177 
1178 	if (attribute && (attribute->device_id_scheme || device_id_scheme)) {
1179 		switch (attribute->display_type) {
1180 		case ACPI_VIDEO_DISPLAY_CRT:
1181 			data->flags.crt = 1;
1182 			break;
1183 		case ACPI_VIDEO_DISPLAY_TV:
1184 			data->flags.tvout = 1;
1185 			break;
1186 		case ACPI_VIDEO_DISPLAY_DVI:
1187 			data->flags.dvi = 1;
1188 			break;
1189 		case ACPI_VIDEO_DISPLAY_LCD:
1190 			data->flags.lcd = 1;
1191 			break;
1192 		default:
1193 			data->flags.unknown = 1;
1194 			break;
1195 		}
1196 		if (attribute->bios_can_detect)
1197 			data->flags.bios = 1;
1198 	} else {
1199 		/* Check for legacy IDs */
1200 		device_type = acpi_video_get_device_type(video, device_id);
1201 		/* Ignore bits 16 and 18-20 */
1202 		switch (device_type & 0xffe2ffff) {
1203 		case ACPI_VIDEO_DISPLAY_LEGACY_MONITOR:
1204 			data->flags.crt = 1;
1205 			break;
1206 		case ACPI_VIDEO_DISPLAY_LEGACY_PANEL:
1207 			data->flags.lcd = 1;
1208 			break;
1209 		case ACPI_VIDEO_DISPLAY_LEGACY_TV:
1210 			data->flags.tvout = 1;
1211 			break;
1212 		default:
1213 			data->flags.unknown = 1;
1214 		}
1215 	}
1216 
1217 	acpi_video_device_bind(video, data);
1218 	acpi_video_device_find_cap(data);
1219 
1220 	mutex_lock(&video->device_list_lock);
1221 	list_add_tail(&data->entry, &video->video_device_list);
1222 	mutex_unlock(&video->device_list_lock);
1223 
1224 	return status;
1225 }
1226 
1227 /*
1228  *  Arg:
1229  *	video	: video bus device
1230  *
1231  *  Return:
1232  *	none
1233  *
1234  *  Enumerate the video device list of the video bus,
1235  *  bind the ids with the corresponding video devices
1236  *  under the video bus.
1237  */
1238 
1239 static void acpi_video_device_rebind(struct acpi_video_bus *video)
1240 {
1241 	struct acpi_video_device *dev;
1242 
1243 	mutex_lock(&video->device_list_lock);
1244 
1245 	list_for_each_entry(dev, &video->video_device_list, entry)
1246 		acpi_video_device_bind(video, dev);
1247 
1248 	mutex_unlock(&video->device_list_lock);
1249 }
1250 
1251 /*
1252  *  Arg:
1253  *	video	: video bus device
1254  *	device	: video output device under the video
1255  *		bus
1256  *
1257  *  Return:
1258  *	none
1259  *
1260  *  Bind the ids with the corresponding video devices
1261  *  under the video bus.
1262  */
1263 
1264 static void
1265 acpi_video_device_bind(struct acpi_video_bus *video,
1266 		       struct acpi_video_device *device)
1267 {
1268 	struct acpi_video_enumerated_device *ids;
1269 	int i;
1270 
1271 	for (i = 0; i < video->attached_count; i++) {
1272 		ids = &video->attached_array[i];
1273 		if (device->device_id == (ids->value.int_val & 0xffff)) {
1274 			ids->bind_info = device;
1275 			ACPI_DEBUG_PRINT((ACPI_DB_INFO, "device_bind %d\n", i));
1276 		}
1277 	}
1278 }
1279 
1280 static bool acpi_video_device_in_dod(struct acpi_video_device *device)
1281 {
1282 	struct acpi_video_bus *video = device->video;
1283 	int i;
1284 
1285 	/*
1286 	 * If we have a broken _DOD or we have more than 8 output devices
1287 	 * under the graphics controller node that we can't proper deal with
1288 	 * in the operation region code currently, no need to test.
1289 	 */
1290 	if (!video->attached_count || video->child_count > 8)
1291 		return true;
1292 
1293 	for (i = 0; i < video->attached_count; i++) {
1294 		if ((video->attached_array[i].value.int_val & 0xfff) ==
1295 		    (device->device_id & 0xfff))
1296 			return true;
1297 	}
1298 
1299 	return false;
1300 }
1301 
1302 /*
1303  *  Arg:
1304  *	video	: video bus device
1305  *
1306  *  Return:
1307  *	< 0	: error
1308  *
1309  *  Call _DOD to enumerate all devices attached to display adapter
1310  *
1311  */
1312 
1313 static int acpi_video_device_enumerate(struct acpi_video_bus *video)
1314 {
1315 	int status;
1316 	int count;
1317 	int i;
1318 	struct acpi_video_enumerated_device *active_list;
1319 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
1320 	union acpi_object *dod = NULL;
1321 	union acpi_object *obj;
1322 
1323 	if (!video->cap._DOD)
1324 		return AE_NOT_EXIST;
1325 
1326 	status = acpi_evaluate_object(video->device->handle, "_DOD", NULL, &buffer);
1327 	if (!ACPI_SUCCESS(status)) {
1328 		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _DOD"));
1329 		return status;
1330 	}
1331 
1332 	dod = buffer.pointer;
1333 	if (!dod || (dod->type != ACPI_TYPE_PACKAGE)) {
1334 		ACPI_EXCEPTION((AE_INFO, status, "Invalid _DOD data"));
1335 		status = -EFAULT;
1336 		goto out;
1337 	}
1338 
1339 	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %d video heads in _DOD\n",
1340 			  dod->package.count));
1341 
1342 	active_list = kcalloc(1 + dod->package.count,
1343 			      sizeof(struct acpi_video_enumerated_device),
1344 			      GFP_KERNEL);
1345 	if (!active_list) {
1346 		status = -ENOMEM;
1347 		goto out;
1348 	}
1349 
1350 	count = 0;
1351 	for (i = 0; i < dod->package.count; i++) {
1352 		obj = &dod->package.elements[i];
1353 
1354 		if (obj->type != ACPI_TYPE_INTEGER) {
1355 			printk(KERN_ERR PREFIX
1356 				"Invalid _DOD data in element %d\n", i);
1357 			continue;
1358 		}
1359 
1360 		active_list[count].value.int_val = obj->integer.value;
1361 		active_list[count].bind_info = NULL;
1362 		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "dod element[%d] = %d\n", i,
1363 				  (int)obj->integer.value));
1364 		count++;
1365 	}
1366 
1367 	kfree(video->attached_array);
1368 
1369 	video->attached_array = active_list;
1370 	video->attached_count = count;
1371 
1372 out:
1373 	kfree(buffer.pointer);
1374 	return status;
1375 }
1376 
1377 static int
1378 acpi_video_get_next_level(struct acpi_video_device *device,
1379 			  u32 level_current, u32 event)
1380 {
1381 	int min, max, min_above, max_below, i, l, delta = 255;
1382 	max = max_below = 0;
1383 	min = min_above = 255;
1384 	/* Find closest level to level_current */
1385 	for (i = ACPI_VIDEO_FIRST_LEVEL; i < device->brightness->count; i++) {
1386 		l = device->brightness->levels[i];
1387 		if (abs(l - level_current) < abs(delta)) {
1388 			delta = l - level_current;
1389 			if (!delta)
1390 				break;
1391 		}
1392 	}
1393 	/* Ajust level_current to closest available level */
1394 	level_current += delta;
1395 	for (i = ACPI_VIDEO_FIRST_LEVEL; i < device->brightness->count; i++) {
1396 		l = device->brightness->levels[i];
1397 		if (l < min)
1398 			min = l;
1399 		if (l > max)
1400 			max = l;
1401 		if (l < min_above && l > level_current)
1402 			min_above = l;
1403 		if (l > max_below && l < level_current)
1404 			max_below = l;
1405 	}
1406 
1407 	switch (event) {
1408 	case ACPI_VIDEO_NOTIFY_CYCLE_BRIGHTNESS:
1409 		return (level_current < max) ? min_above : min;
1410 	case ACPI_VIDEO_NOTIFY_INC_BRIGHTNESS:
1411 		return (level_current < max) ? min_above : max;
1412 	case ACPI_VIDEO_NOTIFY_DEC_BRIGHTNESS:
1413 		return (level_current > min) ? max_below : min;
1414 	case ACPI_VIDEO_NOTIFY_ZERO_BRIGHTNESS:
1415 	case ACPI_VIDEO_NOTIFY_DISPLAY_OFF:
1416 		return 0;
1417 	default:
1418 		return level_current;
1419 	}
1420 }
1421 
1422 static void
1423 acpi_video_switch_brightness(struct work_struct *work)
1424 {
1425 	struct acpi_video_device *device = container_of(to_delayed_work(work),
1426 			     struct acpi_video_device, switch_brightness_work);
1427 	unsigned long long level_current, level_next;
1428 	int event = device->switch_brightness_event;
1429 	int result = -EINVAL;
1430 
1431 	/* no warning message if acpi_backlight=vendor or a quirk is used */
1432 	if (!device->backlight)
1433 		return;
1434 
1435 	if (!device->brightness)
1436 		goto out;
1437 
1438 	result = acpi_video_device_lcd_get_level_current(device,
1439 							 &level_current,
1440 							 false);
1441 	if (result)
1442 		goto out;
1443 
1444 	level_next = acpi_video_get_next_level(device, level_current, event);
1445 
1446 	result = acpi_video_device_lcd_set_level(device, level_next);
1447 
1448 	if (!result)
1449 		backlight_force_update(device->backlight,
1450 				       BACKLIGHT_UPDATE_HOTKEY);
1451 
1452 out:
1453 	if (result)
1454 		printk(KERN_ERR PREFIX "Failed to switch the brightness\n");
1455 }
1456 
1457 int acpi_video_get_edid(struct acpi_device *device, int type, int device_id,
1458 			void **edid)
1459 {
1460 	struct acpi_video_bus *video;
1461 	struct acpi_video_device *video_device;
1462 	union acpi_object *buffer = NULL;
1463 	acpi_status status;
1464 	int i, length;
1465 
1466 	if (!device || !acpi_driver_data(device))
1467 		return -EINVAL;
1468 
1469 	video = acpi_driver_data(device);
1470 
1471 	for (i = 0; i < video->attached_count; i++) {
1472 		video_device = video->attached_array[i].bind_info;
1473 		length = 256;
1474 
1475 		if (!video_device)
1476 			continue;
1477 
1478 		if (!video_device->cap._DDC)
1479 			continue;
1480 
1481 		if (type) {
1482 			switch (type) {
1483 			case ACPI_VIDEO_DISPLAY_CRT:
1484 				if (!video_device->flags.crt)
1485 					continue;
1486 				break;
1487 			case ACPI_VIDEO_DISPLAY_TV:
1488 				if (!video_device->flags.tvout)
1489 					continue;
1490 				break;
1491 			case ACPI_VIDEO_DISPLAY_DVI:
1492 				if (!video_device->flags.dvi)
1493 					continue;
1494 				break;
1495 			case ACPI_VIDEO_DISPLAY_LCD:
1496 				if (!video_device->flags.lcd)
1497 					continue;
1498 				break;
1499 			}
1500 		} else if (video_device->device_id != device_id) {
1501 			continue;
1502 		}
1503 
1504 		status = acpi_video_device_EDID(video_device, &buffer, length);
1505 
1506 		if (ACPI_FAILURE(status) || !buffer ||
1507 		    buffer->type != ACPI_TYPE_BUFFER) {
1508 			length = 128;
1509 			status = acpi_video_device_EDID(video_device, &buffer,
1510 							length);
1511 			if (ACPI_FAILURE(status) || !buffer ||
1512 			    buffer->type != ACPI_TYPE_BUFFER) {
1513 				continue;
1514 			}
1515 		}
1516 
1517 		*edid = buffer->buffer.pointer;
1518 		return length;
1519 	}
1520 
1521 	return -ENODEV;
1522 }
1523 EXPORT_SYMBOL(acpi_video_get_edid);
1524 
1525 static int
1526 acpi_video_bus_get_devices(struct acpi_video_bus *video,
1527 			   struct acpi_device *device)
1528 {
1529 	int status = 0;
1530 	struct acpi_device *dev;
1531 
1532 	/*
1533 	 * There are systems where video module known to work fine regardless
1534 	 * of broken _DOD and ignoring returned value here doesn't cause
1535 	 * any issues later.
1536 	 */
1537 	acpi_video_device_enumerate(video);
1538 
1539 	list_for_each_entry(dev, &device->children, node) {
1540 
1541 		status = acpi_video_bus_get_one_device(dev, video);
1542 		if (status) {
1543 			dev_err(&dev->dev, "Can't attach device\n");
1544 			break;
1545 		}
1546 		video->child_count++;
1547 	}
1548 	return status;
1549 }
1550 
1551 /* acpi_video interface */
1552 
1553 /*
1554  * Win8 requires setting bit2 of _DOS to let firmware know it shouldn't
1555  * preform any automatic brightness change on receiving a notification.
1556  */
1557 static int acpi_video_bus_start_devices(struct acpi_video_bus *video)
1558 {
1559 	return acpi_video_bus_DOS(video, 0,
1560 				  acpi_osi_is_win8() ? 1 : 0);
1561 }
1562 
1563 static int acpi_video_bus_stop_devices(struct acpi_video_bus *video)
1564 {
1565 	return acpi_video_bus_DOS(video, 0,
1566 				  acpi_osi_is_win8() ? 0 : 1);
1567 }
1568 
1569 static void acpi_video_bus_notify(struct acpi_device *device, u32 event)
1570 {
1571 	struct acpi_video_bus *video = acpi_driver_data(device);
1572 	struct input_dev *input;
1573 	int keycode = 0;
1574 
1575 	if (!video || !video->input)
1576 		return;
1577 
1578 	input = video->input;
1579 
1580 	switch (event) {
1581 	case ACPI_VIDEO_NOTIFY_SWITCH:	/* User requested a switch,
1582 					 * most likely via hotkey. */
1583 		keycode = KEY_SWITCHVIDEOMODE;
1584 		break;
1585 
1586 	case ACPI_VIDEO_NOTIFY_PROBE:	/* User plugged in or removed a video
1587 					 * connector. */
1588 		acpi_video_device_enumerate(video);
1589 		acpi_video_device_rebind(video);
1590 		keycode = KEY_SWITCHVIDEOMODE;
1591 		break;
1592 
1593 	case ACPI_VIDEO_NOTIFY_CYCLE:	/* Cycle Display output hotkey pressed. */
1594 		keycode = KEY_SWITCHVIDEOMODE;
1595 		break;
1596 	case ACPI_VIDEO_NOTIFY_NEXT_OUTPUT:	/* Next Display output hotkey pressed. */
1597 		keycode = KEY_VIDEO_NEXT;
1598 		break;
1599 	case ACPI_VIDEO_NOTIFY_PREV_OUTPUT:	/* previous Display output hotkey pressed. */
1600 		keycode = KEY_VIDEO_PREV;
1601 		break;
1602 
1603 	default:
1604 		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
1605 				  "Unsupported event [0x%x]\n", event));
1606 		break;
1607 	}
1608 
1609 	if (acpi_notifier_call_chain(device, event, 0))
1610 		/* Something vetoed the keypress. */
1611 		keycode = 0;
1612 
1613 	if (keycode && (report_key_events & REPORT_OUTPUT_KEY_EVENTS)) {
1614 		input_report_key(input, keycode, 1);
1615 		input_sync(input);
1616 		input_report_key(input, keycode, 0);
1617 		input_sync(input);
1618 	}
1619 
1620 	return;
1621 }
1622 
1623 static void brightness_switch_event(struct acpi_video_device *video_device,
1624 				    u32 event)
1625 {
1626 	if (!brightness_switch_enabled)
1627 		return;
1628 
1629 	video_device->switch_brightness_event = event;
1630 	schedule_delayed_work(&video_device->switch_brightness_work, HZ / 10);
1631 }
1632 
1633 static void acpi_video_device_notify(acpi_handle handle, u32 event, void *data)
1634 {
1635 	struct acpi_video_device *video_device = data;
1636 	struct acpi_device *device = NULL;
1637 	struct acpi_video_bus *bus;
1638 	struct input_dev *input;
1639 	int keycode = 0;
1640 
1641 	if (!video_device)
1642 		return;
1643 
1644 	device = video_device->dev;
1645 	bus = video_device->video;
1646 	input = bus->input;
1647 
1648 	if (hw_changes_brightness > 0) {
1649 		if (video_device->backlight)
1650 			backlight_force_update(video_device->backlight,
1651 					       BACKLIGHT_UPDATE_HOTKEY);
1652 		acpi_notifier_call_chain(device, event, 0);
1653 		return;
1654 	}
1655 
1656 	switch (event) {
1657 	case ACPI_VIDEO_NOTIFY_CYCLE_BRIGHTNESS:	/* Cycle brightness */
1658 		brightness_switch_event(video_device, event);
1659 		keycode = KEY_BRIGHTNESS_CYCLE;
1660 		break;
1661 	case ACPI_VIDEO_NOTIFY_INC_BRIGHTNESS:	/* Increase brightness */
1662 		brightness_switch_event(video_device, event);
1663 		keycode = KEY_BRIGHTNESSUP;
1664 		break;
1665 	case ACPI_VIDEO_NOTIFY_DEC_BRIGHTNESS:	/* Decrease brightness */
1666 		brightness_switch_event(video_device, event);
1667 		keycode = KEY_BRIGHTNESSDOWN;
1668 		break;
1669 	case ACPI_VIDEO_NOTIFY_ZERO_BRIGHTNESS:	/* zero brightness */
1670 		brightness_switch_event(video_device, event);
1671 		keycode = KEY_BRIGHTNESS_ZERO;
1672 		break;
1673 	case ACPI_VIDEO_NOTIFY_DISPLAY_OFF:	/* display device off */
1674 		brightness_switch_event(video_device, event);
1675 		keycode = KEY_DISPLAY_OFF;
1676 		break;
1677 	default:
1678 		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
1679 				  "Unsupported event [0x%x]\n", event));
1680 		break;
1681 	}
1682 
1683 	acpi_notifier_call_chain(device, event, 0);
1684 
1685 	if (keycode && (report_key_events & REPORT_BRIGHTNESS_KEY_EVENTS)) {
1686 		input_report_key(input, keycode, 1);
1687 		input_sync(input);
1688 		input_report_key(input, keycode, 0);
1689 		input_sync(input);
1690 	}
1691 
1692 	return;
1693 }
1694 
1695 static int acpi_video_resume(struct notifier_block *nb,
1696 				unsigned long val, void *ign)
1697 {
1698 	struct acpi_video_bus *video;
1699 	struct acpi_video_device *video_device;
1700 	int i;
1701 
1702 	switch (val) {
1703 	case PM_HIBERNATION_PREPARE:
1704 	case PM_SUSPEND_PREPARE:
1705 	case PM_RESTORE_PREPARE:
1706 		return NOTIFY_DONE;
1707 	}
1708 
1709 	video = container_of(nb, struct acpi_video_bus, pm_nb);
1710 
1711 	dev_info(&video->device->dev, "Restoring backlight state\n");
1712 
1713 	for (i = 0; i < video->attached_count; i++) {
1714 		video_device = video->attached_array[i].bind_info;
1715 		if (video_device && video_device->brightness)
1716 			acpi_video_device_lcd_set_level(video_device,
1717 					video_device->brightness->curr);
1718 	}
1719 
1720 	return NOTIFY_OK;
1721 }
1722 
1723 static acpi_status
1724 acpi_video_bus_match(acpi_handle handle, u32 level, void *context,
1725 			void **return_value)
1726 {
1727 	struct acpi_device *device = context;
1728 	struct acpi_device *sibling;
1729 	int result;
1730 
1731 	if (handle == device->handle)
1732 		return AE_CTRL_TERMINATE;
1733 
1734 	result = acpi_bus_get_device(handle, &sibling);
1735 	if (result)
1736 		return AE_OK;
1737 
1738 	if (!strcmp(acpi_device_name(sibling), ACPI_VIDEO_BUS_NAME))
1739 			return AE_ALREADY_EXISTS;
1740 
1741 	return AE_OK;
1742 }
1743 
1744 static void acpi_video_dev_register_backlight(struct acpi_video_device *device)
1745 {
1746 	struct backlight_properties props;
1747 	struct pci_dev *pdev;
1748 	acpi_handle acpi_parent;
1749 	struct device *parent = NULL;
1750 	int result;
1751 	static int count;
1752 	char *name;
1753 
1754 	result = acpi_video_init_brightness(device);
1755 	if (result)
1756 		return;
1757 
1758 	if (disable_backlight_sysfs_if > 0)
1759 		return;
1760 
1761 	name = kasprintf(GFP_KERNEL, "acpi_video%d", count);
1762 	if (!name)
1763 		return;
1764 	count++;
1765 
1766 	acpi_get_parent(device->dev->handle, &acpi_parent);
1767 
1768 	pdev = acpi_get_pci_dev(acpi_parent);
1769 	if (pdev) {
1770 		parent = &pdev->dev;
1771 		pci_dev_put(pdev);
1772 	}
1773 
1774 	memset(&props, 0, sizeof(struct backlight_properties));
1775 	props.type = BACKLIGHT_FIRMWARE;
1776 	props.max_brightness =
1777 		device->brightness->count - ACPI_VIDEO_FIRST_LEVEL - 1;
1778 	device->backlight = backlight_device_register(name,
1779 						      parent,
1780 						      device,
1781 						      &acpi_backlight_ops,
1782 						      &props);
1783 	kfree(name);
1784 	if (IS_ERR(device->backlight)) {
1785 		device->backlight = NULL;
1786 		return;
1787 	}
1788 
1789 	/*
1790 	 * Save current brightness level in case we have to restore it
1791 	 * before acpi_video_device_lcd_set_level() is called next time.
1792 	 */
1793 	device->backlight->props.brightness =
1794 			acpi_video_get_brightness(device->backlight);
1795 
1796 	device->cooling_dev = thermal_cooling_device_register("LCD",
1797 				device->dev, &video_cooling_ops);
1798 	if (IS_ERR(device->cooling_dev)) {
1799 		/*
1800 		 * Set cooling_dev to NULL so we don't crash trying to free it.
1801 		 * Also, why the hell we are returning early and not attempt to
1802 		 * register video output if cooling device registration failed?
1803 		 * -- dtor
1804 		 */
1805 		device->cooling_dev = NULL;
1806 		return;
1807 	}
1808 
1809 	dev_info(&device->dev->dev, "registered as cooling_device%d\n",
1810 		 device->cooling_dev->id);
1811 	result = sysfs_create_link(&device->dev->dev.kobj,
1812 			&device->cooling_dev->device.kobj,
1813 			"thermal_cooling");
1814 	if (result)
1815 		printk(KERN_ERR PREFIX "Create sysfs link\n");
1816 	result = sysfs_create_link(&device->cooling_dev->device.kobj,
1817 			&device->dev->dev.kobj, "device");
1818 	if (result)
1819 		printk(KERN_ERR PREFIX "Create sysfs link\n");
1820 }
1821 
1822 static void acpi_video_run_bcl_for_osi(struct acpi_video_bus *video)
1823 {
1824 	struct acpi_video_device *dev;
1825 	union acpi_object *levels;
1826 
1827 	mutex_lock(&video->device_list_lock);
1828 	list_for_each_entry(dev, &video->video_device_list, entry) {
1829 		if (!acpi_video_device_lcd_query_levels(dev->dev->handle, &levels))
1830 			kfree(levels);
1831 	}
1832 	mutex_unlock(&video->device_list_lock);
1833 }
1834 
1835 static bool acpi_video_should_register_backlight(struct acpi_video_device *dev)
1836 {
1837 	/*
1838 	 * Do not create backlight device for video output
1839 	 * device that is not in the enumerated list.
1840 	 */
1841 	if (!acpi_video_device_in_dod(dev)) {
1842 		dev_dbg(&dev->dev->dev, "not in _DOD list, ignore\n");
1843 		return false;
1844 	}
1845 
1846 	if (only_lcd)
1847 		return dev->flags.lcd;
1848 	return true;
1849 }
1850 
1851 static int acpi_video_bus_register_backlight(struct acpi_video_bus *video)
1852 {
1853 	struct acpi_video_device *dev;
1854 
1855 	if (video->backlight_registered)
1856 		return 0;
1857 
1858 	acpi_video_run_bcl_for_osi(video);
1859 
1860 	if (acpi_video_get_backlight_type() != acpi_backlight_video)
1861 		return 0;
1862 
1863 	mutex_lock(&video->device_list_lock);
1864 	list_for_each_entry(dev, &video->video_device_list, entry) {
1865 		if (acpi_video_should_register_backlight(dev))
1866 			acpi_video_dev_register_backlight(dev);
1867 	}
1868 	mutex_unlock(&video->device_list_lock);
1869 
1870 	video->backlight_registered = true;
1871 
1872 	video->pm_nb.notifier_call = acpi_video_resume;
1873 	video->pm_nb.priority = 0;
1874 	return register_pm_notifier(&video->pm_nb);
1875 }
1876 
1877 static void acpi_video_dev_unregister_backlight(struct acpi_video_device *device)
1878 {
1879 	if (device->backlight) {
1880 		backlight_device_unregister(device->backlight);
1881 		device->backlight = NULL;
1882 	}
1883 	if (device->brightness) {
1884 		kfree(device->brightness->levels);
1885 		kfree(device->brightness);
1886 		device->brightness = NULL;
1887 	}
1888 	if (device->cooling_dev) {
1889 		sysfs_remove_link(&device->dev->dev.kobj, "thermal_cooling");
1890 		sysfs_remove_link(&device->cooling_dev->device.kobj, "device");
1891 		thermal_cooling_device_unregister(device->cooling_dev);
1892 		device->cooling_dev = NULL;
1893 	}
1894 }
1895 
1896 static int acpi_video_bus_unregister_backlight(struct acpi_video_bus *video)
1897 {
1898 	struct acpi_video_device *dev;
1899 	int error;
1900 
1901 	if (!video->backlight_registered)
1902 		return 0;
1903 
1904 	error = unregister_pm_notifier(&video->pm_nb);
1905 
1906 	mutex_lock(&video->device_list_lock);
1907 	list_for_each_entry(dev, &video->video_device_list, entry)
1908 		acpi_video_dev_unregister_backlight(dev);
1909 	mutex_unlock(&video->device_list_lock);
1910 
1911 	video->backlight_registered = false;
1912 
1913 	return error;
1914 }
1915 
1916 static void acpi_video_dev_add_notify_handler(struct acpi_video_device *device)
1917 {
1918 	acpi_status status;
1919 	struct acpi_device *adev = device->dev;
1920 
1921 	status = acpi_install_notify_handler(adev->handle, ACPI_DEVICE_NOTIFY,
1922 					     acpi_video_device_notify, device);
1923 	if (ACPI_FAILURE(status))
1924 		dev_err(&adev->dev, "Error installing notify handler\n");
1925 	else
1926 		device->flags.notify = 1;
1927 }
1928 
1929 static int acpi_video_bus_add_notify_handler(struct acpi_video_bus *video)
1930 {
1931 	struct input_dev *input;
1932 	struct acpi_video_device *dev;
1933 	int error;
1934 
1935 	video->input = input = input_allocate_device();
1936 	if (!input) {
1937 		error = -ENOMEM;
1938 		goto out;
1939 	}
1940 
1941 	error = acpi_video_bus_start_devices(video);
1942 	if (error)
1943 		goto err_free_input;
1944 
1945 	snprintf(video->phys, sizeof(video->phys),
1946 			"%s/video/input0", acpi_device_hid(video->device));
1947 
1948 	input->name = acpi_device_name(video->device);
1949 	input->phys = video->phys;
1950 	input->id.bustype = BUS_HOST;
1951 	input->id.product = 0x06;
1952 	input->dev.parent = &video->device->dev;
1953 	input->evbit[0] = BIT(EV_KEY);
1954 	set_bit(KEY_SWITCHVIDEOMODE, input->keybit);
1955 	set_bit(KEY_VIDEO_NEXT, input->keybit);
1956 	set_bit(KEY_VIDEO_PREV, input->keybit);
1957 	set_bit(KEY_BRIGHTNESS_CYCLE, input->keybit);
1958 	set_bit(KEY_BRIGHTNESSUP, input->keybit);
1959 	set_bit(KEY_BRIGHTNESSDOWN, input->keybit);
1960 	set_bit(KEY_BRIGHTNESS_ZERO, input->keybit);
1961 	set_bit(KEY_DISPLAY_OFF, input->keybit);
1962 
1963 	error = input_register_device(input);
1964 	if (error)
1965 		goto err_stop_dev;
1966 
1967 	mutex_lock(&video->device_list_lock);
1968 	list_for_each_entry(dev, &video->video_device_list, entry)
1969 		acpi_video_dev_add_notify_handler(dev);
1970 	mutex_unlock(&video->device_list_lock);
1971 
1972 	return 0;
1973 
1974 err_stop_dev:
1975 	acpi_video_bus_stop_devices(video);
1976 err_free_input:
1977 	input_free_device(input);
1978 	video->input = NULL;
1979 out:
1980 	return error;
1981 }
1982 
1983 static void acpi_video_dev_remove_notify_handler(struct acpi_video_device *dev)
1984 {
1985 	if (dev->flags.notify) {
1986 		acpi_remove_notify_handler(dev->dev->handle, ACPI_DEVICE_NOTIFY,
1987 					   acpi_video_device_notify);
1988 		dev->flags.notify = 0;
1989 	}
1990 }
1991 
1992 static void acpi_video_bus_remove_notify_handler(struct acpi_video_bus *video)
1993 {
1994 	struct acpi_video_device *dev;
1995 
1996 	mutex_lock(&video->device_list_lock);
1997 	list_for_each_entry(dev, &video->video_device_list, entry)
1998 		acpi_video_dev_remove_notify_handler(dev);
1999 	mutex_unlock(&video->device_list_lock);
2000 
2001 	acpi_video_bus_stop_devices(video);
2002 	input_unregister_device(video->input);
2003 	video->input = NULL;
2004 }
2005 
2006 static int acpi_video_bus_put_devices(struct acpi_video_bus *video)
2007 {
2008 	struct acpi_video_device *dev, *next;
2009 
2010 	mutex_lock(&video->device_list_lock);
2011 	list_for_each_entry_safe(dev, next, &video->video_device_list, entry) {
2012 		list_del(&dev->entry);
2013 		kfree(dev);
2014 	}
2015 	mutex_unlock(&video->device_list_lock);
2016 
2017 	return 0;
2018 }
2019 
2020 static int instance;
2021 
2022 static int acpi_video_bus_add(struct acpi_device *device)
2023 {
2024 	struct acpi_video_bus *video;
2025 	int error;
2026 	acpi_status status;
2027 
2028 	status = acpi_walk_namespace(ACPI_TYPE_DEVICE,
2029 				device->parent->handle, 1,
2030 				acpi_video_bus_match, NULL,
2031 				device, NULL);
2032 	if (status == AE_ALREADY_EXISTS) {
2033 		printk(KERN_WARNING FW_BUG
2034 			"Duplicate ACPI video bus devices for the"
2035 			" same VGA controller, please try module "
2036 			"parameter \"video.allow_duplicates=1\""
2037 			"if the current driver doesn't work.\n");
2038 		if (!allow_duplicates)
2039 			return -ENODEV;
2040 	}
2041 
2042 	video = kzalloc(sizeof(struct acpi_video_bus), GFP_KERNEL);
2043 	if (!video)
2044 		return -ENOMEM;
2045 
2046 	/* a hack to fix the duplicate name "VID" problem on T61 */
2047 	if (!strcmp(device->pnp.bus_id, "VID")) {
2048 		if (instance)
2049 			device->pnp.bus_id[3] = '0' + instance;
2050 		instance++;
2051 	}
2052 	/* a hack to fix the duplicate name "VGA" problem on Pa 3553 */
2053 	if (!strcmp(device->pnp.bus_id, "VGA")) {
2054 		if (instance)
2055 			device->pnp.bus_id[3] = '0' + instance;
2056 		instance++;
2057 	}
2058 
2059 	video->device = device;
2060 	strcpy(acpi_device_name(device), ACPI_VIDEO_BUS_NAME);
2061 	strcpy(acpi_device_class(device), ACPI_VIDEO_CLASS);
2062 	device->driver_data = video;
2063 
2064 	acpi_video_bus_find_cap(video);
2065 	error = acpi_video_bus_check(video);
2066 	if (error)
2067 		goto err_free_video;
2068 
2069 	mutex_init(&video->device_list_lock);
2070 	INIT_LIST_HEAD(&video->video_device_list);
2071 
2072 	error = acpi_video_bus_get_devices(video, device);
2073 	if (error)
2074 		goto err_put_video;
2075 
2076 	printk(KERN_INFO PREFIX "%s [%s] (multi-head: %s  rom: %s  post: %s)\n",
2077 	       ACPI_VIDEO_DEVICE_NAME, acpi_device_bid(device),
2078 	       video->flags.multihead ? "yes" : "no",
2079 	       video->flags.rom ? "yes" : "no",
2080 	       video->flags.post ? "yes" : "no");
2081 	mutex_lock(&video_list_lock);
2082 	list_add_tail(&video->entry, &video_bus_head);
2083 	mutex_unlock(&video_list_lock);
2084 
2085 	acpi_video_bus_register_backlight(video);
2086 	acpi_video_bus_add_notify_handler(video);
2087 
2088 	return 0;
2089 
2090 err_put_video:
2091 	acpi_video_bus_put_devices(video);
2092 	kfree(video->attached_array);
2093 err_free_video:
2094 	kfree(video);
2095 	device->driver_data = NULL;
2096 
2097 	return error;
2098 }
2099 
2100 static int acpi_video_bus_remove(struct acpi_device *device)
2101 {
2102 	struct acpi_video_bus *video = NULL;
2103 
2104 
2105 	if (!device || !acpi_driver_data(device))
2106 		return -EINVAL;
2107 
2108 	video = acpi_driver_data(device);
2109 
2110 	acpi_video_bus_remove_notify_handler(video);
2111 	acpi_video_bus_unregister_backlight(video);
2112 	acpi_video_bus_put_devices(video);
2113 
2114 	mutex_lock(&video_list_lock);
2115 	list_del(&video->entry);
2116 	mutex_unlock(&video_list_lock);
2117 
2118 	kfree(video->attached_array);
2119 	kfree(video);
2120 
2121 	return 0;
2122 }
2123 
2124 static int __init is_i740(struct pci_dev *dev)
2125 {
2126 	if (dev->device == 0x00D1)
2127 		return 1;
2128 	if (dev->device == 0x7000)
2129 		return 1;
2130 	return 0;
2131 }
2132 
2133 static int __init intel_opregion_present(void)
2134 {
2135 	int opregion = 0;
2136 	struct pci_dev *dev = NULL;
2137 	u32 address;
2138 
2139 	for_each_pci_dev(dev) {
2140 		if ((dev->class >> 8) != PCI_CLASS_DISPLAY_VGA)
2141 			continue;
2142 		if (dev->vendor != PCI_VENDOR_ID_INTEL)
2143 			continue;
2144 		/* We don't want to poke around undefined i740 registers */
2145 		if (is_i740(dev))
2146 			continue;
2147 		pci_read_config_dword(dev, 0xfc, &address);
2148 		if (!address)
2149 			continue;
2150 		opregion = 1;
2151 	}
2152 	return opregion;
2153 }
2154 
2155 /* Check if the chassis-type indicates there is no builtin LCD panel */
2156 static bool dmi_is_desktop(void)
2157 {
2158 	const char *chassis_type;
2159 	unsigned long type;
2160 
2161 	chassis_type = dmi_get_system_info(DMI_CHASSIS_TYPE);
2162 	if (!chassis_type)
2163 		return false;
2164 
2165 	if (kstrtoul(chassis_type, 10, &type) != 0)
2166 		return false;
2167 
2168 	switch (type) {
2169 	case 0x03: /* Desktop */
2170 	case 0x04: /* Low Profile Desktop */
2171 	case 0x05: /* Pizza Box */
2172 	case 0x06: /* Mini Tower */
2173 	case 0x07: /* Tower */
2174 	case 0x10: /* Lunch Box */
2175 	case 0x11: /* Main Server Chassis */
2176 		return true;
2177 	}
2178 
2179 	return false;
2180 }
2181 
2182 int acpi_video_register(void)
2183 {
2184 	int ret = 0;
2185 
2186 	mutex_lock(&register_count_mutex);
2187 	if (register_count) {
2188 		/*
2189 		 * if the function of acpi_video_register is already called,
2190 		 * don't register the acpi_video_bus again and return no error.
2191 		 */
2192 		goto leave;
2193 	}
2194 
2195 	/*
2196 	 * We're seeing a lot of bogus backlight interfaces on newer machines
2197 	 * without a LCD such as desktops, servers and HDMI sticks. Checking
2198 	 * the lcd flag fixes this, so enable this on any machines which are
2199 	 * win8 ready (where we also prefer the native backlight driver, so
2200 	 * normally the acpi_video code should not register there anyways).
2201 	 */
2202 	if (only_lcd == -1) {
2203 		if (dmi_is_desktop() && acpi_osi_is_win8())
2204 			only_lcd = true;
2205 		else
2206 			only_lcd = false;
2207 	}
2208 
2209 	dmi_check_system(video_dmi_table);
2210 
2211 	ret = acpi_bus_register_driver(&acpi_video_bus);
2212 	if (ret)
2213 		goto leave;
2214 
2215 	/*
2216 	 * When the acpi_video_bus is loaded successfully, increase
2217 	 * the counter reference.
2218 	 */
2219 	register_count = 1;
2220 
2221 leave:
2222 	mutex_unlock(&register_count_mutex);
2223 	return ret;
2224 }
2225 EXPORT_SYMBOL(acpi_video_register);
2226 
2227 void acpi_video_unregister(void)
2228 {
2229 	mutex_lock(&register_count_mutex);
2230 	if (register_count) {
2231 		acpi_bus_unregister_driver(&acpi_video_bus);
2232 		register_count = 0;
2233 	}
2234 	mutex_unlock(&register_count_mutex);
2235 }
2236 EXPORT_SYMBOL(acpi_video_unregister);
2237 
2238 void acpi_video_unregister_backlight(void)
2239 {
2240 	struct acpi_video_bus *video;
2241 
2242 	mutex_lock(&register_count_mutex);
2243 	if (register_count) {
2244 		mutex_lock(&video_list_lock);
2245 		list_for_each_entry(video, &video_bus_head, entry)
2246 			acpi_video_bus_unregister_backlight(video);
2247 		mutex_unlock(&video_list_lock);
2248 	}
2249 	mutex_unlock(&register_count_mutex);
2250 }
2251 
2252 bool acpi_video_handles_brightness_key_presses(void)
2253 {
2254 	bool have_video_busses;
2255 
2256 	mutex_lock(&video_list_lock);
2257 	have_video_busses = !list_empty(&video_bus_head);
2258 	mutex_unlock(&video_list_lock);
2259 
2260 	return have_video_busses &&
2261 	       (report_key_events & REPORT_BRIGHTNESS_KEY_EVENTS);
2262 }
2263 EXPORT_SYMBOL(acpi_video_handles_brightness_key_presses);
2264 
2265 /*
2266  * This is kind of nasty. Hardware using Intel chipsets may require
2267  * the video opregion code to be run first in order to initialise
2268  * state before any ACPI video calls are made. To handle this we defer
2269  * registration of the video class until the opregion code has run.
2270  */
2271 
2272 static int __init acpi_video_init(void)
2273 {
2274 	/*
2275 	 * Let the module load even if ACPI is disabled (e.g. due to
2276 	 * a broken BIOS) so that i915.ko can still be loaded on such
2277 	 * old systems without an AcpiOpRegion.
2278 	 *
2279 	 * acpi_video_register() will report -ENODEV later as well due
2280 	 * to acpi_disabled when i915.ko tries to register itself afterwards.
2281 	 */
2282 	if (acpi_disabled)
2283 		return 0;
2284 
2285 	if (intel_opregion_present())
2286 		return 0;
2287 
2288 	return acpi_video_register();
2289 }
2290 
2291 static void __exit acpi_video_exit(void)
2292 {
2293 	acpi_video_detect_exit();
2294 	acpi_video_unregister();
2295 
2296 	return;
2297 }
2298 
2299 module_init(acpi_video_init);
2300 module_exit(acpi_video_exit);
2301