xref: /linux/drivers/acpi/acpi_video.c (revision 87c9c16317882dd6dbbc07e349bc3223e14f3244)
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 int register_count;
77 static DEFINE_MUTEX(register_count_mutex);
78 static DEFINE_MUTEX(video_list_lock);
79 static LIST_HEAD(video_bus_head);
80 static int acpi_video_bus_add(struct acpi_device *device);
81 static int acpi_video_bus_remove(struct acpi_device *device);
82 static void acpi_video_bus_notify(struct acpi_device *device, u32 event);
83 void acpi_video_detect_exit(void);
84 
85 /*
86  * Indices in the _BCL method response: the first two items are special,
87  * the rest are all supported levels.
88  *
89  * See page 575 of the ACPI spec 3.0
90  */
91 enum acpi_video_level_idx {
92 	ACPI_VIDEO_AC_LEVEL,		/* level when machine has full power */
93 	ACPI_VIDEO_BATTERY_LEVEL,	/* level when machine is on batteries */
94 	ACPI_VIDEO_FIRST_LEVEL,		/* actual supported levels begin here */
95 };
96 
97 static const struct acpi_device_id video_device_ids[] = {
98 	{ACPI_VIDEO_HID, 0},
99 	{"", 0},
100 };
101 MODULE_DEVICE_TABLE(acpi, video_device_ids);
102 
103 static struct acpi_driver acpi_video_bus = {
104 	.name = "video",
105 	.class = ACPI_VIDEO_CLASS,
106 	.ids = video_device_ids,
107 	.ops = {
108 		.add = acpi_video_bus_add,
109 		.remove = acpi_video_bus_remove,
110 		.notify = acpi_video_bus_notify,
111 		},
112 };
113 
114 struct acpi_video_bus_flags {
115 	u8 multihead:1;		/* can switch video heads */
116 	u8 rom:1;		/* can retrieve a video rom */
117 	u8 post:1;		/* can configure the head to */
118 	u8 reserved:5;
119 };
120 
121 struct acpi_video_bus_cap {
122 	u8 _DOS:1;		/* Enable/Disable output switching */
123 	u8 _DOD:1;		/* Enumerate all devices attached to display adapter */
124 	u8 _ROM:1;		/* Get ROM Data */
125 	u8 _GPD:1;		/* Get POST Device */
126 	u8 _SPD:1;		/* Set POST Device */
127 	u8 _VPO:1;		/* Video POST Options */
128 	u8 reserved:2;
129 };
130 
131 struct acpi_video_device_attrib {
132 	u32 display_index:4;	/* A zero-based instance of the Display */
133 	u32 display_port_attachment:4;	/* This field differentiates the display type */
134 	u32 display_type:4;	/* Describe the specific type in use */
135 	u32 vendor_specific:4;	/* Chipset Vendor Specific */
136 	u32 bios_can_detect:1;	/* BIOS can detect the device */
137 	u32 depend_on_vga:1;	/* Non-VGA output device whose power is related to
138 				   the VGA device. */
139 	u32 pipe_id:3;		/* For VGA multiple-head devices. */
140 	u32 reserved:10;	/* Must be 0 */
141 
142 	/*
143 	 * The device ID might not actually follow the scheme described by this
144 	 * struct acpi_video_device_attrib. If it does, then this bit
145 	 * device_id_scheme is set; otherwise, other fields should be ignored.
146 	 *
147 	 * (but also see the global flag device_id_scheme)
148 	 */
149 	u32 device_id_scheme:1;
150 };
151 
152 struct acpi_video_enumerated_device {
153 	union {
154 		u32 int_val;
155 		struct acpi_video_device_attrib attrib;
156 	} value;
157 	struct acpi_video_device *bind_info;
158 };
159 
160 struct acpi_video_bus {
161 	struct acpi_device *device;
162 	bool backlight_registered;
163 	u8 dos_setting;
164 	struct acpi_video_enumerated_device *attached_array;
165 	u8 attached_count;
166 	u8 child_count;
167 	struct acpi_video_bus_cap cap;
168 	struct acpi_video_bus_flags flags;
169 	struct list_head video_device_list;
170 	struct mutex device_list_lock;	/* protects video_device_list */
171 	struct list_head entry;
172 	struct input_dev *input;
173 	char phys[32];	/* for input device */
174 	struct notifier_block pm_nb;
175 };
176 
177 struct acpi_video_device_flags {
178 	u8 crt:1;
179 	u8 lcd:1;
180 	u8 tvout:1;
181 	u8 dvi:1;
182 	u8 bios:1;
183 	u8 unknown:1;
184 	u8 notify:1;
185 	u8 reserved:1;
186 };
187 
188 struct acpi_video_device_cap {
189 	u8 _ADR:1;		/* Return the unique ID */
190 	u8 _BCL:1;		/* Query list of brightness control levels supported */
191 	u8 _BCM:1;		/* Set the brightness level */
192 	u8 _BQC:1;		/* Get current brightness level */
193 	u8 _BCQ:1;		/* Some buggy BIOS uses _BCQ instead of _BQC */
194 	u8 _DDC:1;		/* Return the EDID for this device */
195 };
196 
197 struct acpi_video_device {
198 	unsigned long device_id;
199 	struct acpi_video_device_flags flags;
200 	struct acpi_video_device_cap cap;
201 	struct list_head entry;
202 	struct delayed_work switch_brightness_work;
203 	int switch_brightness_event;
204 	struct acpi_video_bus *video;
205 	struct acpi_device *dev;
206 	struct acpi_video_device_brightness *brightness;
207 	struct backlight_device *backlight;
208 	struct thermal_cooling_device *cooling_dev;
209 };
210 
211 static void acpi_video_device_notify(acpi_handle handle, u32 event, void *data);
212 static void acpi_video_device_rebind(struct acpi_video_bus *video);
213 static void acpi_video_device_bind(struct acpi_video_bus *video,
214 				   struct acpi_video_device *device);
215 static int acpi_video_device_enumerate(struct acpi_video_bus *video);
216 static int acpi_video_device_lcd_set_level(struct acpi_video_device *device,
217 			int level);
218 static int acpi_video_device_lcd_get_level_current(
219 			struct acpi_video_device *device,
220 			unsigned long long *level, bool raw);
221 static int acpi_video_get_next_level(struct acpi_video_device *device,
222 				     u32 level_current, u32 event);
223 static void acpi_video_switch_brightness(struct work_struct *work);
224 
225 /* backlight device sysfs support */
226 static int acpi_video_get_brightness(struct backlight_device *bd)
227 {
228 	unsigned long long cur_level;
229 	int i;
230 	struct acpi_video_device *vd = bl_get_data(bd);
231 
232 	if (acpi_video_device_lcd_get_level_current(vd, &cur_level, false))
233 		return -EINVAL;
234 	for (i = ACPI_VIDEO_FIRST_LEVEL; i < vd->brightness->count; i++) {
235 		if (vd->brightness->levels[i] == cur_level)
236 			return i - ACPI_VIDEO_FIRST_LEVEL;
237 	}
238 	return 0;
239 }
240 
241 static int acpi_video_set_brightness(struct backlight_device *bd)
242 {
243 	int request_level = bd->props.brightness + ACPI_VIDEO_FIRST_LEVEL;
244 	struct acpi_video_device *vd = bl_get_data(bd);
245 
246 	cancel_delayed_work(&vd->switch_brightness_work);
247 	return acpi_video_device_lcd_set_level(vd,
248 				vd->brightness->levels[request_level]);
249 }
250 
251 static const struct backlight_ops acpi_backlight_ops = {
252 	.get_brightness = acpi_video_get_brightness,
253 	.update_status  = acpi_video_set_brightness,
254 };
255 
256 /* thermal cooling device callbacks */
257 static int video_get_max_state(struct thermal_cooling_device *cooling_dev,
258 			       unsigned long *state)
259 {
260 	struct acpi_device *device = cooling_dev->devdata;
261 	struct acpi_video_device *video = acpi_driver_data(device);
262 
263 	*state = video->brightness->count - ACPI_VIDEO_FIRST_LEVEL - 1;
264 	return 0;
265 }
266 
267 static int video_get_cur_state(struct thermal_cooling_device *cooling_dev,
268 			       unsigned long *state)
269 {
270 	struct acpi_device *device = cooling_dev->devdata;
271 	struct acpi_video_device *video = acpi_driver_data(device);
272 	unsigned long long level;
273 	int offset;
274 
275 	if (acpi_video_device_lcd_get_level_current(video, &level, false))
276 		return -EINVAL;
277 	for (offset = ACPI_VIDEO_FIRST_LEVEL; offset < video->brightness->count;
278 	     offset++)
279 		if (level == video->brightness->levels[offset]) {
280 			*state = video->brightness->count - offset - 1;
281 			return 0;
282 		}
283 
284 	return -EINVAL;
285 }
286 
287 static int
288 video_set_cur_state(struct thermal_cooling_device *cooling_dev, unsigned long state)
289 {
290 	struct acpi_device *device = cooling_dev->devdata;
291 	struct acpi_video_device *video = acpi_driver_data(device);
292 	int level;
293 
294 	if (state >= video->brightness->count - ACPI_VIDEO_FIRST_LEVEL)
295 		return -EINVAL;
296 
297 	state = video->brightness->count - state;
298 	level = video->brightness->levels[state - 1];
299 	return acpi_video_device_lcd_set_level(video, level);
300 }
301 
302 static const struct thermal_cooling_device_ops video_cooling_ops = {
303 	.get_max_state = video_get_max_state,
304 	.get_cur_state = video_get_cur_state,
305 	.set_cur_state = video_set_cur_state,
306 };
307 
308 /*
309  * --------------------------------------------------------------------------
310  *                             Video Management
311  * --------------------------------------------------------------------------
312  */
313 
314 static int
315 acpi_video_device_lcd_query_levels(acpi_handle handle,
316 				   union acpi_object **levels)
317 {
318 	int status;
319 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
320 	union acpi_object *obj;
321 
322 
323 	*levels = NULL;
324 
325 	status = acpi_evaluate_object(handle, "_BCL", NULL, &buffer);
326 	if (ACPI_FAILURE(status))
327 		return status;
328 	obj = (union acpi_object *)buffer.pointer;
329 	if (!obj || (obj->type != ACPI_TYPE_PACKAGE)) {
330 		acpi_handle_info(handle, "Invalid _BCL data\n");
331 		status = -EFAULT;
332 		goto err;
333 	}
334 
335 	*levels = obj;
336 
337 	return 0;
338 
339 err:
340 	kfree(buffer.pointer);
341 
342 	return status;
343 }
344 
345 static int
346 acpi_video_device_lcd_set_level(struct acpi_video_device *device, int level)
347 {
348 	int status;
349 	int state;
350 
351 	status = acpi_execute_simple_method(device->dev->handle,
352 					    "_BCM", level);
353 	if (ACPI_FAILURE(status)) {
354 		acpi_handle_info(device->dev->handle, "_BCM evaluation failed\n");
355 		return -EIO;
356 	}
357 
358 	device->brightness->curr = level;
359 	for (state = ACPI_VIDEO_FIRST_LEVEL; state < device->brightness->count;
360 	     state++)
361 		if (level == device->brightness->levels[state]) {
362 			if (device->backlight)
363 				device->backlight->props.brightness =
364 					state - ACPI_VIDEO_FIRST_LEVEL;
365 			return 0;
366 		}
367 
368 	acpi_handle_info(device->dev->handle, "Current brightness invalid\n");
369 	return -EINVAL;
370 }
371 
372 /*
373  * For some buggy _BQC methods, we need to add a constant value to
374  * the _BQC return value to get the actual current brightness level
375  */
376 
377 static int bqc_offset_aml_bug_workaround;
378 static int video_set_bqc_offset(const struct dmi_system_id *d)
379 {
380 	bqc_offset_aml_bug_workaround = 9;
381 	return 0;
382 }
383 
384 static int video_disable_backlight_sysfs_if(
385 	const struct dmi_system_id *d)
386 {
387 	if (disable_backlight_sysfs_if == -1)
388 		disable_backlight_sysfs_if = 1;
389 	return 0;
390 }
391 
392 static int video_set_device_id_scheme(const struct dmi_system_id *d)
393 {
394 	device_id_scheme = true;
395 	return 0;
396 }
397 
398 static int video_enable_only_lcd(const struct dmi_system_id *d)
399 {
400 	only_lcd = true;
401 	return 0;
402 }
403 
404 static int video_set_report_key_events(const struct dmi_system_id *id)
405 {
406 	if (report_key_events == -1)
407 		report_key_events = (uintptr_t)id->driver_data;
408 	return 0;
409 }
410 
411 static int video_hw_changes_brightness(
412 	const struct dmi_system_id *d)
413 {
414 	if (hw_changes_brightness == -1)
415 		hw_changes_brightness = 1;
416 	return 0;
417 }
418 
419 static const struct dmi_system_id video_dmi_table[] = {
420 	/*
421 	 * Broken _BQC workaround http://bugzilla.kernel.org/show_bug.cgi?id=13121
422 	 */
423 	{
424 	 .callback = video_set_bqc_offset,
425 	 .ident = "Acer Aspire 5720",
426 	 .matches = {
427 		DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
428 		DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5720"),
429 		},
430 	},
431 	{
432 	 .callback = video_set_bqc_offset,
433 	 .ident = "Acer Aspire 5710Z",
434 	 .matches = {
435 		DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
436 		DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5710Z"),
437 		},
438 	},
439 	{
440 	 .callback = video_set_bqc_offset,
441 	 .ident = "eMachines E510",
442 	 .matches = {
443 		DMI_MATCH(DMI_BOARD_VENDOR, "EMACHINES"),
444 		DMI_MATCH(DMI_PRODUCT_NAME, "eMachines E510"),
445 		},
446 	},
447 	{
448 	 .callback = video_set_bqc_offset,
449 	 .ident = "Acer Aspire 5315",
450 	 .matches = {
451 		DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
452 		DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5315"),
453 		},
454 	},
455 	{
456 	 .callback = video_set_bqc_offset,
457 	 .ident = "Acer Aspire 7720",
458 	 .matches = {
459 		DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
460 		DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 7720"),
461 		},
462 	},
463 
464 	/*
465 	 * Some machines have a broken acpi-video interface for brightness
466 	 * control, but still need an acpi_video_device_lcd_set_level() call
467 	 * on resume to turn the backlight power on.  We Enable backlight
468 	 * control on these systems, but do not register a backlight sysfs
469 	 * as brightness control does not work.
470 	 */
471 	{
472 	 /* https://bugzilla.kernel.org/show_bug.cgi?id=21012 */
473 	 .callback = video_disable_backlight_sysfs_if,
474 	 .ident = "Toshiba Portege R700",
475 	 .matches = {
476 		DMI_MATCH(DMI_SYS_VENDOR, "TOSHIBA"),
477 		DMI_MATCH(DMI_PRODUCT_NAME, "PORTEGE R700"),
478 		},
479 	},
480 	{
481 	 /* https://bugs.freedesktop.org/show_bug.cgi?id=82634 */
482 	 .callback = video_disable_backlight_sysfs_if,
483 	 .ident = "Toshiba Portege R830",
484 	 .matches = {
485 		DMI_MATCH(DMI_SYS_VENDOR, "TOSHIBA"),
486 		DMI_MATCH(DMI_PRODUCT_NAME, "PORTEGE R830"),
487 		},
488 	},
489 	{
490 	 /* https://bugzilla.kernel.org/show_bug.cgi?id=21012 */
491 	 .callback = video_disable_backlight_sysfs_if,
492 	 .ident = "Toshiba Satellite R830",
493 	 .matches = {
494 		DMI_MATCH(DMI_SYS_VENDOR, "TOSHIBA"),
495 		DMI_MATCH(DMI_PRODUCT_NAME, "SATELLITE R830"),
496 		},
497 	},
498 	/*
499 	 * Some machine's _DOD IDs don't have bit 31(Device ID Scheme) set
500 	 * but the IDs actually follow the Device ID Scheme.
501 	 */
502 	{
503 	 /* https://bugzilla.kernel.org/show_bug.cgi?id=104121 */
504 	 .callback = video_set_device_id_scheme,
505 	 .ident = "ESPRIMO Mobile M9410",
506 	 .matches = {
507 		DMI_MATCH(DMI_SYS_VENDOR, "FUJITSU SIEMENS"),
508 		DMI_MATCH(DMI_PRODUCT_NAME, "ESPRIMO Mobile M9410"),
509 		},
510 	},
511 	/*
512 	 * Some machines have multiple video output devices, but only the one
513 	 * that is the type of LCD can do the backlight control so we should not
514 	 * register backlight interface for other video output devices.
515 	 */
516 	{
517 	 /* https://bugzilla.kernel.org/show_bug.cgi?id=104121 */
518 	 .callback = video_enable_only_lcd,
519 	 .ident = "ESPRIMO Mobile M9410",
520 	 .matches = {
521 		DMI_MATCH(DMI_SYS_VENDOR, "FUJITSU SIEMENS"),
522 		DMI_MATCH(DMI_PRODUCT_NAME, "ESPRIMO Mobile M9410"),
523 		},
524 	},
525 	/*
526 	 * Some machines report wrong key events on the acpi-bus, suppress
527 	 * key event reporting on these.  Note this is only intended to work
528 	 * around events which are plain wrong. In some cases we get double
529 	 * events, in this case acpi-video is considered the canonical source
530 	 * and the events from the other source should be filtered. E.g.
531 	 * by calling acpi_video_handles_brightness_key_presses() from the
532 	 * vendor acpi/wmi driver or by using /lib/udev/hwdb.d/60-keyboard.hwdb
533 	 */
534 	{
535 	 .callback = video_set_report_key_events,
536 	 .driver_data = (void *)((uintptr_t)REPORT_OUTPUT_KEY_EVENTS),
537 	 .ident = "Dell Vostro V131",
538 	 .matches = {
539 		DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
540 		DMI_MATCH(DMI_PRODUCT_NAME, "Vostro V131"),
541 		},
542 	},
543 	/*
544 	 * Some machines change the brightness themselves when a brightness
545 	 * hotkey gets pressed, despite us telling them not to. In this case
546 	 * acpi_video_device_notify() should only call backlight_force_update(
547 	 * BACKLIGHT_UPDATE_HOTKEY) and not do anything else.
548 	 */
549 	{
550 	 /* https://bugzilla.kernel.org/show_bug.cgi?id=204077 */
551 	 .callback = video_hw_changes_brightness,
552 	 .ident = "Packard Bell EasyNote MZ35",
553 	 .matches = {
554 		DMI_MATCH(DMI_SYS_VENDOR, "Packard Bell"),
555 		DMI_MATCH(DMI_PRODUCT_NAME, "EasyNote MZ35"),
556 		},
557 	},
558 	{}
559 };
560 
561 static unsigned long long
562 acpi_video_bqc_value_to_level(struct acpi_video_device *device,
563 			      unsigned long long bqc_value)
564 {
565 	unsigned long long level;
566 
567 	if (device->brightness->flags._BQC_use_index) {
568 		/*
569 		 * _BQC returns an index that doesn't account for the first 2
570 		 * items with special meaning (see enum acpi_video_level_idx),
571 		 * so we need to compensate for that by offsetting ourselves
572 		 */
573 		if (device->brightness->flags._BCL_reversed)
574 			bqc_value = device->brightness->count -
575 				ACPI_VIDEO_FIRST_LEVEL - 1 - bqc_value;
576 
577 		level = device->brightness->levels[bqc_value +
578 						   ACPI_VIDEO_FIRST_LEVEL];
579 	} else {
580 		level = bqc_value;
581 	}
582 
583 	level += bqc_offset_aml_bug_workaround;
584 
585 	return level;
586 }
587 
588 static int
589 acpi_video_device_lcd_get_level_current(struct acpi_video_device *device,
590 					unsigned long long *level, bool raw)
591 {
592 	acpi_status status = AE_OK;
593 	int i;
594 
595 	if (device->cap._BQC || device->cap._BCQ) {
596 		char *buf = device->cap._BQC ? "_BQC" : "_BCQ";
597 
598 		status = acpi_evaluate_integer(device->dev->handle, buf,
599 						NULL, level);
600 		if (ACPI_SUCCESS(status)) {
601 			if (raw) {
602 				/*
603 				 * Caller has indicated he wants the raw
604 				 * value returned by _BQC, so don't furtherly
605 				 * mess with the value.
606 				 */
607 				return 0;
608 			}
609 
610 			*level = acpi_video_bqc_value_to_level(device, *level);
611 
612 			for (i = ACPI_VIDEO_FIRST_LEVEL;
613 			     i < device->brightness->count; i++)
614 				if (device->brightness->levels[i] == *level) {
615 					device->brightness->curr = *level;
616 					return 0;
617 				}
618 			/*
619 			 * BQC returned an invalid level.
620 			 * Stop using it.
621 			 */
622 			acpi_handle_info(device->dev->handle,
623 					 "%s returned an invalid level", buf);
624 			device->cap._BQC = device->cap._BCQ = 0;
625 		} else {
626 			/*
627 			 * Fixme:
628 			 * should we return an error or ignore this failure?
629 			 * dev->brightness->curr is a cached value which stores
630 			 * the correct current backlight level in most cases.
631 			 * ACPI video backlight still works w/ buggy _BQC.
632 			 * http://bugzilla.kernel.org/show_bug.cgi?id=12233
633 			 */
634 			acpi_handle_info(device->dev->handle,
635 					 "%s evaluation failed", buf);
636 			device->cap._BQC = device->cap._BCQ = 0;
637 		}
638 	}
639 
640 	*level = device->brightness->curr;
641 	return 0;
642 }
643 
644 static int
645 acpi_video_device_EDID(struct acpi_video_device *device,
646 		       union acpi_object **edid, ssize_t length)
647 {
648 	int status;
649 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
650 	union acpi_object *obj;
651 	union acpi_object arg0 = { ACPI_TYPE_INTEGER };
652 	struct acpi_object_list args = { 1, &arg0 };
653 
654 
655 	*edid = NULL;
656 
657 	if (!device)
658 		return -ENODEV;
659 	if (length == 128)
660 		arg0.integer.value = 1;
661 	else if (length == 256)
662 		arg0.integer.value = 2;
663 	else
664 		return -EINVAL;
665 
666 	status = acpi_evaluate_object(device->dev->handle, "_DDC", &args, &buffer);
667 	if (ACPI_FAILURE(status))
668 		return -ENODEV;
669 
670 	obj = buffer.pointer;
671 
672 	if (obj && obj->type == ACPI_TYPE_BUFFER)
673 		*edid = obj;
674 	else {
675 		acpi_handle_info(device->dev->handle, "Invalid _DDC data\n");
676 		status = -EFAULT;
677 		kfree(obj);
678 	}
679 
680 	return status;
681 }
682 
683 /* bus */
684 
685 /*
686  *  Arg:
687  *	video		: video bus device pointer
688  *	bios_flag	:
689  *		0.	The system BIOS should NOT automatically switch(toggle)
690  *			the active display output.
691  *		1.	The system BIOS should automatically switch (toggle) the
692  *			active display output. No switch event.
693  *		2.	The _DGS value should be locked.
694  *		3.	The system BIOS should not automatically switch (toggle) the
695  *			active display output, but instead generate the display switch
696  *			event notify code.
697  *	lcd_flag	:
698  *		0.	The system BIOS should automatically control the brightness level
699  *			of the LCD when:
700  *			- the power changes from AC to DC (ACPI appendix B)
701  *			- a brightness hotkey gets pressed (implied by Win7/8 backlight docs)
702  *		1.	The system BIOS should NOT automatically control the brightness
703  *			level of the LCD when:
704  *			- the power changes from AC to DC (ACPI appendix B)
705  *			- a brightness hotkey gets pressed (implied by Win7/8 backlight docs)
706  *  Return Value:
707  *		-EINVAL	wrong arg.
708  */
709 
710 static int
711 acpi_video_bus_DOS(struct acpi_video_bus *video, int bios_flag, int lcd_flag)
712 {
713 	acpi_status status;
714 
715 	if (!video->cap._DOS)
716 		return 0;
717 
718 	if (bios_flag < 0 || bios_flag > 3 || lcd_flag < 0 || lcd_flag > 1)
719 		return -EINVAL;
720 	video->dos_setting = (lcd_flag << 2) | bios_flag;
721 	status = acpi_execute_simple_method(video->device->handle, "_DOS",
722 					    (lcd_flag << 2) | bios_flag);
723 	if (ACPI_FAILURE(status))
724 		return -EIO;
725 
726 	return 0;
727 }
728 
729 /*
730  * Simple comparison function used to sort backlight levels.
731  */
732 
733 static int
734 acpi_video_cmp_level(const void *a, const void *b)
735 {
736 	return *(int *)a - *(int *)b;
737 }
738 
739 /*
740  * Decides if _BQC/_BCQ for this system is usable
741  *
742  * We do this by changing the level first and then read out the current
743  * brightness level, if the value does not match, find out if it is using
744  * index. If not, clear the _BQC/_BCQ capability.
745  */
746 static int acpi_video_bqc_quirk(struct acpi_video_device *device,
747 				int max_level, int current_level)
748 {
749 	struct acpi_video_device_brightness *br = device->brightness;
750 	int result;
751 	unsigned long long level;
752 	int test_level;
753 
754 	/* don't mess with existing known broken systems */
755 	if (bqc_offset_aml_bug_workaround)
756 		return 0;
757 
758 	/*
759 	 * Some systems always report current brightness level as maximum
760 	 * through _BQC, we need to test another value for them. However,
761 	 * there is a subtlety:
762 	 *
763 	 * If the _BCL package ordering is descending, the first level
764 	 * (br->levels[2]) is likely to be 0, and if the number of levels
765 	 * matches the number of steps, we might confuse a returned level to
766 	 * mean the index.
767 	 *
768 	 * For example:
769 	 *
770 	 *     current_level = max_level = 100
771 	 *     test_level = 0
772 	 *     returned level = 100
773 	 *
774 	 * In this case 100 means the level, not the index, and _BCM failed.
775 	 * Still, if the _BCL package ordering is descending, the index of
776 	 * level 0 is also 100, so we assume _BQC is indexed, when it's not.
777 	 *
778 	 * This causes all _BQC calls to return bogus values causing weird
779 	 * behavior from the user's perspective.  For example:
780 	 *
781 	 * xbacklight -set 10; xbacklight -set 20;
782 	 *
783 	 * would flash to 90% and then slowly down to the desired level (20).
784 	 *
785 	 * The solution is simple; test anything other than the first level
786 	 * (e.g. 1).
787 	 */
788 	test_level = current_level == max_level
789 		? br->levels[ACPI_VIDEO_FIRST_LEVEL + 1]
790 		: max_level;
791 
792 	result = acpi_video_device_lcd_set_level(device, test_level);
793 	if (result)
794 		return result;
795 
796 	result = acpi_video_device_lcd_get_level_current(device, &level, true);
797 	if (result)
798 		return result;
799 
800 	if (level != test_level) {
801 		/* buggy _BQC found, need to find out if it uses index */
802 		if (level < br->count) {
803 			if (br->flags._BCL_reversed)
804 				level = br->count - ACPI_VIDEO_FIRST_LEVEL - 1 - level;
805 			if (br->levels[level + ACPI_VIDEO_FIRST_LEVEL] == test_level)
806 				br->flags._BQC_use_index = 1;
807 		}
808 
809 		if (!br->flags._BQC_use_index)
810 			device->cap._BQC = device->cap._BCQ = 0;
811 	}
812 
813 	return 0;
814 }
815 
816 int acpi_video_get_levels(struct acpi_device *device,
817 			  struct acpi_video_device_brightness **dev_br,
818 			  int *pmax_level)
819 {
820 	union acpi_object *obj = NULL;
821 	int i, max_level = 0, count = 0, level_ac_battery = 0;
822 	union acpi_object *o;
823 	struct acpi_video_device_brightness *br = NULL;
824 	int result = 0;
825 	u32 value;
826 
827 	if (ACPI_FAILURE(acpi_video_device_lcd_query_levels(device->handle, &obj))) {
828 		acpi_handle_debug(device->handle,
829 				  "Could not query available LCD brightness level\n");
830 		result = -ENODEV;
831 		goto out;
832 	}
833 
834 	if (obj->package.count < ACPI_VIDEO_FIRST_LEVEL) {
835 		result = -EINVAL;
836 		goto out;
837 	}
838 
839 	br = kzalloc(sizeof(*br), GFP_KERNEL);
840 	if (!br) {
841 		result = -ENOMEM;
842 		goto out;
843 	}
844 
845 	/*
846 	 * Note that we have to reserve 2 extra items (ACPI_VIDEO_FIRST_LEVEL),
847 	 * in order to account for buggy BIOS which don't export the first two
848 	 * special levels (see below)
849 	 */
850 	br->levels = kmalloc_array(obj->package.count + ACPI_VIDEO_FIRST_LEVEL,
851 				   sizeof(*br->levels),
852 				   GFP_KERNEL);
853 	if (!br->levels) {
854 		result = -ENOMEM;
855 		goto out_free;
856 	}
857 
858 	for (i = 0; i < obj->package.count; i++) {
859 		o = (union acpi_object *)&obj->package.elements[i];
860 		if (o->type != ACPI_TYPE_INTEGER) {
861 			acpi_handle_info(device->handle, "Invalid data\n");
862 			continue;
863 		}
864 		value = (u32) o->integer.value;
865 		/* Skip duplicate entries */
866 		if (count > ACPI_VIDEO_FIRST_LEVEL
867 		    && br->levels[count - 1] == value)
868 			continue;
869 
870 		br->levels[count] = value;
871 
872 		if (br->levels[count] > max_level)
873 			max_level = br->levels[count];
874 		count++;
875 	}
876 
877 	/*
878 	 * some buggy BIOS don't export the levels
879 	 * when machine is on AC/Battery in _BCL package.
880 	 * In this case, the first two elements in _BCL packages
881 	 * are also supported brightness levels that OS should take care of.
882 	 */
883 	for (i = ACPI_VIDEO_FIRST_LEVEL; i < count; i++) {
884 		if (br->levels[i] == br->levels[ACPI_VIDEO_AC_LEVEL])
885 			level_ac_battery++;
886 		if (br->levels[i] == br->levels[ACPI_VIDEO_BATTERY_LEVEL])
887 			level_ac_battery++;
888 	}
889 
890 	if (level_ac_battery < ACPI_VIDEO_FIRST_LEVEL) {
891 		level_ac_battery = ACPI_VIDEO_FIRST_LEVEL - level_ac_battery;
892 		br->flags._BCL_no_ac_battery_levels = 1;
893 		for (i = (count - 1 + level_ac_battery);
894 		     i >= ACPI_VIDEO_FIRST_LEVEL; i--)
895 			br->levels[i] = br->levels[i - level_ac_battery];
896 		count += level_ac_battery;
897 	} else if (level_ac_battery > ACPI_VIDEO_FIRST_LEVEL)
898 		acpi_handle_info(device->handle,
899 				 "Too many duplicates in _BCL package");
900 
901 	/* Check if the _BCL package is in a reversed order */
902 	if (max_level == br->levels[ACPI_VIDEO_FIRST_LEVEL]) {
903 		br->flags._BCL_reversed = 1;
904 		sort(&br->levels[ACPI_VIDEO_FIRST_LEVEL],
905 		     count - ACPI_VIDEO_FIRST_LEVEL,
906 		     sizeof(br->levels[ACPI_VIDEO_FIRST_LEVEL]),
907 		     acpi_video_cmp_level, NULL);
908 	} else if (max_level != br->levels[count - 1])
909 		acpi_handle_info(device->handle,
910 				 "Found unordered _BCL package");
911 
912 	br->count = count;
913 	*dev_br = br;
914 	if (pmax_level)
915 		*pmax_level = max_level;
916 
917 out:
918 	kfree(obj);
919 	return result;
920 out_free:
921 	kfree(br);
922 	goto out;
923 }
924 EXPORT_SYMBOL(acpi_video_get_levels);
925 
926 /*
927  *  Arg:
928  *	device	: video output device (LCD, CRT, ..)
929  *
930  *  Return Value:
931  *	Maximum brightness level
932  *
933  *  Allocate and initialize device->brightness.
934  */
935 
936 static int
937 acpi_video_init_brightness(struct acpi_video_device *device)
938 {
939 	int i, max_level = 0;
940 	unsigned long long level, level_old;
941 	struct acpi_video_device_brightness *br = NULL;
942 	int result;
943 
944 	result = acpi_video_get_levels(device->dev, &br, &max_level);
945 	if (result)
946 		return result;
947 	device->brightness = br;
948 
949 	/* _BQC uses INDEX while _BCL uses VALUE in some laptops */
950 	br->curr = level = max_level;
951 
952 	if (!device->cap._BQC)
953 		goto set_level;
954 
955 	result = acpi_video_device_lcd_get_level_current(device,
956 							 &level_old, true);
957 	if (result)
958 		goto out_free_levels;
959 
960 	result = acpi_video_bqc_quirk(device, max_level, level_old);
961 	if (result)
962 		goto out_free_levels;
963 	/*
964 	 * cap._BQC may get cleared due to _BQC is found to be broken
965 	 * in acpi_video_bqc_quirk, so check again here.
966 	 */
967 	if (!device->cap._BQC)
968 		goto set_level;
969 
970 	level = acpi_video_bqc_value_to_level(device, level_old);
971 	/*
972 	 * On some buggy laptops, _BQC returns an uninitialized
973 	 * value when invoked for the first time, i.e.
974 	 * level_old is invalid (no matter whether it's a level
975 	 * or an index). Set the backlight to max_level in this case.
976 	 */
977 	for (i = ACPI_VIDEO_FIRST_LEVEL; i < br->count; i++)
978 		if (level == br->levels[i])
979 			break;
980 	if (i == br->count || !level)
981 		level = max_level;
982 
983 set_level:
984 	result = acpi_video_device_lcd_set_level(device, level);
985 	if (result)
986 		goto out_free_levels;
987 
988 	acpi_handle_debug(device->dev->handle, "found %d brightness levels\n",
989 			  br->count - ACPI_VIDEO_FIRST_LEVEL);
990 
991 	return 0;
992 
993 out_free_levels:
994 	kfree(br->levels);
995 	kfree(br);
996 	device->brightness = NULL;
997 	return result;
998 }
999 
1000 /*
1001  *  Arg:
1002  *	device	: video output device (LCD, CRT, ..)
1003  *
1004  *  Return Value:
1005  *	None
1006  *
1007  *  Find out all required AML methods defined under the output
1008  *  device.
1009  */
1010 
1011 static void acpi_video_device_find_cap(struct acpi_video_device *device)
1012 {
1013 	if (acpi_has_method(device->dev->handle, "_ADR"))
1014 		device->cap._ADR = 1;
1015 	if (acpi_has_method(device->dev->handle, "_BCL"))
1016 		device->cap._BCL = 1;
1017 	if (acpi_has_method(device->dev->handle, "_BCM"))
1018 		device->cap._BCM = 1;
1019 	if (acpi_has_method(device->dev->handle, "_BQC")) {
1020 		device->cap._BQC = 1;
1021 	} else if (acpi_has_method(device->dev->handle, "_BCQ")) {
1022 		acpi_handle_info(device->dev->handle,
1023 				 "_BCQ is used instead of _BQC\n");
1024 		device->cap._BCQ = 1;
1025 	}
1026 
1027 	if (acpi_has_method(device->dev->handle, "_DDC"))
1028 		device->cap._DDC = 1;
1029 }
1030 
1031 /*
1032  *  Arg:
1033  *	device	: video output device (VGA)
1034  *
1035  *  Return Value:
1036  *	None
1037  *
1038  *  Find out all required AML methods defined under the video bus device.
1039  */
1040 
1041 static void acpi_video_bus_find_cap(struct acpi_video_bus *video)
1042 {
1043 	if (acpi_has_method(video->device->handle, "_DOS"))
1044 		video->cap._DOS = 1;
1045 	if (acpi_has_method(video->device->handle, "_DOD"))
1046 		video->cap._DOD = 1;
1047 	if (acpi_has_method(video->device->handle, "_ROM"))
1048 		video->cap._ROM = 1;
1049 	if (acpi_has_method(video->device->handle, "_GPD"))
1050 		video->cap._GPD = 1;
1051 	if (acpi_has_method(video->device->handle, "_SPD"))
1052 		video->cap._SPD = 1;
1053 	if (acpi_has_method(video->device->handle, "_VPO"))
1054 		video->cap._VPO = 1;
1055 }
1056 
1057 /*
1058  * Check whether the video bus device has required AML method to
1059  * support the desired features
1060  */
1061 
1062 static int acpi_video_bus_check(struct acpi_video_bus *video)
1063 {
1064 	acpi_status status = -ENOENT;
1065 	struct pci_dev *dev;
1066 
1067 	if (!video)
1068 		return -EINVAL;
1069 
1070 	dev = acpi_get_pci_dev(video->device->handle);
1071 	if (!dev)
1072 		return -ENODEV;
1073 	pci_dev_put(dev);
1074 
1075 	/*
1076 	 * Since there is no HID, CID and so on for VGA driver, we have
1077 	 * to check well known required nodes.
1078 	 */
1079 
1080 	/* Does this device support video switching? */
1081 	if (video->cap._DOS || video->cap._DOD) {
1082 		if (!video->cap._DOS) {
1083 			pr_info(FW_BUG "ACPI(%s) defines _DOD but not _DOS\n",
1084 				acpi_device_bid(video->device));
1085 		}
1086 		video->flags.multihead = 1;
1087 		status = 0;
1088 	}
1089 
1090 	/* Does this device support retrieving a video ROM? */
1091 	if (video->cap._ROM) {
1092 		video->flags.rom = 1;
1093 		status = 0;
1094 	}
1095 
1096 	/* Does this device support configuring which video device to POST? */
1097 	if (video->cap._GPD && video->cap._SPD && video->cap._VPO) {
1098 		video->flags.post = 1;
1099 		status = 0;
1100 	}
1101 
1102 	return status;
1103 }
1104 
1105 /*
1106  * --------------------------------------------------------------------------
1107  *                               Driver Interface
1108  * --------------------------------------------------------------------------
1109  */
1110 
1111 /* device interface */
1112 static struct acpi_video_device_attrib *
1113 acpi_video_get_device_attr(struct acpi_video_bus *video, unsigned long device_id)
1114 {
1115 	struct acpi_video_enumerated_device *ids;
1116 	int i;
1117 
1118 	for (i = 0; i < video->attached_count; i++) {
1119 		ids = &video->attached_array[i];
1120 		if ((ids->value.int_val & 0xffff) == device_id)
1121 			return &ids->value.attrib;
1122 	}
1123 
1124 	return NULL;
1125 }
1126 
1127 static int
1128 acpi_video_get_device_type(struct acpi_video_bus *video,
1129 			   unsigned long device_id)
1130 {
1131 	struct acpi_video_enumerated_device *ids;
1132 	int i;
1133 
1134 	for (i = 0; i < video->attached_count; i++) {
1135 		ids = &video->attached_array[i];
1136 		if ((ids->value.int_val & 0xffff) == device_id)
1137 			return ids->value.int_val;
1138 	}
1139 
1140 	return 0;
1141 }
1142 
1143 static int
1144 acpi_video_bus_get_one_device(struct acpi_device *device,
1145 			      struct acpi_video_bus *video)
1146 {
1147 	unsigned long long device_id;
1148 	int status, device_type;
1149 	struct acpi_video_device *data;
1150 	struct acpi_video_device_attrib *attribute;
1151 
1152 	status =
1153 	    acpi_evaluate_integer(device->handle, "_ADR", NULL, &device_id);
1154 	/* Some device omits _ADR, we skip them instead of fail */
1155 	if (ACPI_FAILURE(status))
1156 		return 0;
1157 
1158 	data = kzalloc(sizeof(struct acpi_video_device), GFP_KERNEL);
1159 	if (!data)
1160 		return -ENOMEM;
1161 
1162 	strcpy(acpi_device_name(device), ACPI_VIDEO_DEVICE_NAME);
1163 	strcpy(acpi_device_class(device), ACPI_VIDEO_CLASS);
1164 	device->driver_data = data;
1165 
1166 	data->device_id = device_id;
1167 	data->video = video;
1168 	data->dev = device;
1169 	INIT_DELAYED_WORK(&data->switch_brightness_work,
1170 			  acpi_video_switch_brightness);
1171 
1172 	attribute = acpi_video_get_device_attr(video, device_id);
1173 
1174 	if (attribute && (attribute->device_id_scheme || device_id_scheme)) {
1175 		switch (attribute->display_type) {
1176 		case ACPI_VIDEO_DISPLAY_CRT:
1177 			data->flags.crt = 1;
1178 			break;
1179 		case ACPI_VIDEO_DISPLAY_TV:
1180 			data->flags.tvout = 1;
1181 			break;
1182 		case ACPI_VIDEO_DISPLAY_DVI:
1183 			data->flags.dvi = 1;
1184 			break;
1185 		case ACPI_VIDEO_DISPLAY_LCD:
1186 			data->flags.lcd = 1;
1187 			break;
1188 		default:
1189 			data->flags.unknown = 1;
1190 			break;
1191 		}
1192 		if (attribute->bios_can_detect)
1193 			data->flags.bios = 1;
1194 	} else {
1195 		/* Check for legacy IDs */
1196 		device_type = acpi_video_get_device_type(video, device_id);
1197 		/* Ignore bits 16 and 18-20 */
1198 		switch (device_type & 0xffe2ffff) {
1199 		case ACPI_VIDEO_DISPLAY_LEGACY_MONITOR:
1200 			data->flags.crt = 1;
1201 			break;
1202 		case ACPI_VIDEO_DISPLAY_LEGACY_PANEL:
1203 			data->flags.lcd = 1;
1204 			break;
1205 		case ACPI_VIDEO_DISPLAY_LEGACY_TV:
1206 			data->flags.tvout = 1;
1207 			break;
1208 		default:
1209 			data->flags.unknown = 1;
1210 		}
1211 	}
1212 
1213 	acpi_video_device_bind(video, data);
1214 	acpi_video_device_find_cap(data);
1215 
1216 	mutex_lock(&video->device_list_lock);
1217 	list_add_tail(&data->entry, &video->video_device_list);
1218 	mutex_unlock(&video->device_list_lock);
1219 
1220 	return status;
1221 }
1222 
1223 /*
1224  *  Arg:
1225  *	video	: video bus device
1226  *
1227  *  Return:
1228  *	none
1229  *
1230  *  Enumerate the video device list of the video bus,
1231  *  bind the ids with the corresponding video devices
1232  *  under the video bus.
1233  */
1234 
1235 static void acpi_video_device_rebind(struct acpi_video_bus *video)
1236 {
1237 	struct acpi_video_device *dev;
1238 
1239 	mutex_lock(&video->device_list_lock);
1240 
1241 	list_for_each_entry(dev, &video->video_device_list, entry)
1242 		acpi_video_device_bind(video, dev);
1243 
1244 	mutex_unlock(&video->device_list_lock);
1245 }
1246 
1247 /*
1248  *  Arg:
1249  *	video	: video bus device
1250  *	device	: video output device under the video
1251  *		bus
1252  *
1253  *  Return:
1254  *	none
1255  *
1256  *  Bind the ids with the corresponding video devices
1257  *  under the video bus.
1258  */
1259 
1260 static void
1261 acpi_video_device_bind(struct acpi_video_bus *video,
1262 		       struct acpi_video_device *device)
1263 {
1264 	struct acpi_video_enumerated_device *ids;
1265 	int i;
1266 
1267 	for (i = 0; i < video->attached_count; i++) {
1268 		ids = &video->attached_array[i];
1269 		if (device->device_id == (ids->value.int_val & 0xffff)) {
1270 			ids->bind_info = device;
1271 			acpi_handle_debug(video->device->handle, "%s: %d\n",
1272 					  __func__, i);
1273 		}
1274 	}
1275 }
1276 
1277 static bool acpi_video_device_in_dod(struct acpi_video_device *device)
1278 {
1279 	struct acpi_video_bus *video = device->video;
1280 	int i;
1281 
1282 	/*
1283 	 * If we have a broken _DOD or we have more than 8 output devices
1284 	 * under the graphics controller node that we can't proper deal with
1285 	 * in the operation region code currently, no need to test.
1286 	 */
1287 	if (!video->attached_count || video->child_count > 8)
1288 		return true;
1289 
1290 	for (i = 0; i < video->attached_count; i++) {
1291 		if ((video->attached_array[i].value.int_val & 0xfff) ==
1292 		    (device->device_id & 0xfff))
1293 			return true;
1294 	}
1295 
1296 	return false;
1297 }
1298 
1299 /*
1300  *  Arg:
1301  *	video	: video bus device
1302  *
1303  *  Return:
1304  *	< 0	: error
1305  *
1306  *  Call _DOD to enumerate all devices attached to display adapter
1307  *
1308  */
1309 
1310 static int acpi_video_device_enumerate(struct acpi_video_bus *video)
1311 {
1312 	int status;
1313 	int count;
1314 	int i;
1315 	struct acpi_video_enumerated_device *active_list;
1316 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
1317 	union acpi_object *dod = NULL;
1318 	union acpi_object *obj;
1319 
1320 	if (!video->cap._DOD)
1321 		return AE_NOT_EXIST;
1322 
1323 	status = acpi_evaluate_object(video->device->handle, "_DOD", NULL, &buffer);
1324 	if (ACPI_FAILURE(status)) {
1325 		acpi_handle_info(video->device->handle,
1326 				 "_DOD evaluation failed: %s\n",
1327 				 acpi_format_exception(status));
1328 		return status;
1329 	}
1330 
1331 	dod = buffer.pointer;
1332 	if (!dod || (dod->type != ACPI_TYPE_PACKAGE)) {
1333 		acpi_handle_info(video->device->handle, "Invalid _DOD data\n");
1334 		status = -EFAULT;
1335 		goto out;
1336 	}
1337 
1338 	acpi_handle_debug(video->device->handle, "Found %d video heads in _DOD\n",
1339 			  dod->package.count);
1340 
1341 	active_list = kcalloc(1 + dod->package.count,
1342 			      sizeof(struct acpi_video_enumerated_device),
1343 			      GFP_KERNEL);
1344 	if (!active_list) {
1345 		status = -ENOMEM;
1346 		goto out;
1347 	}
1348 
1349 	count = 0;
1350 	for (i = 0; i < dod->package.count; i++) {
1351 		obj = &dod->package.elements[i];
1352 
1353 		if (obj->type != ACPI_TYPE_INTEGER) {
1354 			acpi_handle_info(video->device->handle,
1355 					 "Invalid _DOD data in element %d\n", i);
1356 			continue;
1357 		}
1358 
1359 		active_list[count].value.int_val = obj->integer.value;
1360 		active_list[count].bind_info = NULL;
1361 
1362 		acpi_handle_debug(video->device->handle,
1363 				  "_DOD element[%d] = %d\n", i,
1364 				  (int)obj->integer.value);
1365 
1366 		count++;
1367 	}
1368 
1369 	kfree(video->attached_array);
1370 
1371 	video->attached_array = active_list;
1372 	video->attached_count = count;
1373 
1374 out:
1375 	kfree(buffer.pointer);
1376 	return status;
1377 }
1378 
1379 static int
1380 acpi_video_get_next_level(struct acpi_video_device *device,
1381 			  u32 level_current, u32 event)
1382 {
1383 	int min, max, min_above, max_below, i, l, delta = 255;
1384 	max = max_below = 0;
1385 	min = min_above = 255;
1386 	/* Find closest level to level_current */
1387 	for (i = ACPI_VIDEO_FIRST_LEVEL; i < device->brightness->count; i++) {
1388 		l = device->brightness->levels[i];
1389 		if (abs(l - level_current) < abs(delta)) {
1390 			delta = l - level_current;
1391 			if (!delta)
1392 				break;
1393 		}
1394 	}
1395 	/* Adjust level_current to closest available level */
1396 	level_current += delta;
1397 	for (i = ACPI_VIDEO_FIRST_LEVEL; i < device->brightness->count; i++) {
1398 		l = device->brightness->levels[i];
1399 		if (l < min)
1400 			min = l;
1401 		if (l > max)
1402 			max = l;
1403 		if (l < min_above && l > level_current)
1404 			min_above = l;
1405 		if (l > max_below && l < level_current)
1406 			max_below = l;
1407 	}
1408 
1409 	switch (event) {
1410 	case ACPI_VIDEO_NOTIFY_CYCLE_BRIGHTNESS:
1411 		return (level_current < max) ? min_above : min;
1412 	case ACPI_VIDEO_NOTIFY_INC_BRIGHTNESS:
1413 		return (level_current < max) ? min_above : max;
1414 	case ACPI_VIDEO_NOTIFY_DEC_BRIGHTNESS:
1415 		return (level_current > min) ? max_below : min;
1416 	case ACPI_VIDEO_NOTIFY_ZERO_BRIGHTNESS:
1417 	case ACPI_VIDEO_NOTIFY_DISPLAY_OFF:
1418 		return 0;
1419 	default:
1420 		return level_current;
1421 	}
1422 }
1423 
1424 static void
1425 acpi_video_switch_brightness(struct work_struct *work)
1426 {
1427 	struct acpi_video_device *device = container_of(to_delayed_work(work),
1428 			     struct acpi_video_device, switch_brightness_work);
1429 	unsigned long long level_current, level_next;
1430 	int event = device->switch_brightness_event;
1431 	int result = -EINVAL;
1432 
1433 	/* no warning message if acpi_backlight=vendor or a quirk is used */
1434 	if (!device->backlight)
1435 		return;
1436 
1437 	if (!device->brightness)
1438 		goto out;
1439 
1440 	result = acpi_video_device_lcd_get_level_current(device,
1441 							 &level_current,
1442 							 false);
1443 	if (result)
1444 		goto out;
1445 
1446 	level_next = acpi_video_get_next_level(device, level_current, event);
1447 
1448 	result = acpi_video_device_lcd_set_level(device, level_next);
1449 
1450 	if (!result)
1451 		backlight_force_update(device->backlight,
1452 				       BACKLIGHT_UPDATE_HOTKEY);
1453 
1454 out:
1455 	if (result)
1456 		acpi_handle_info(device->dev->handle,
1457 				 "Failed to switch brightness\n");
1458 }
1459 
1460 int acpi_video_get_edid(struct acpi_device *device, int type, int device_id,
1461 			void **edid)
1462 {
1463 	struct acpi_video_bus *video;
1464 	struct acpi_video_device *video_device;
1465 	union acpi_object *buffer = NULL;
1466 	acpi_status status;
1467 	int i, length;
1468 
1469 	if (!device || !acpi_driver_data(device))
1470 		return -EINVAL;
1471 
1472 	video = acpi_driver_data(device);
1473 
1474 	for (i = 0; i < video->attached_count; i++) {
1475 		video_device = video->attached_array[i].bind_info;
1476 		length = 256;
1477 
1478 		if (!video_device)
1479 			continue;
1480 
1481 		if (!video_device->cap._DDC)
1482 			continue;
1483 
1484 		if (type) {
1485 			switch (type) {
1486 			case ACPI_VIDEO_DISPLAY_CRT:
1487 				if (!video_device->flags.crt)
1488 					continue;
1489 				break;
1490 			case ACPI_VIDEO_DISPLAY_TV:
1491 				if (!video_device->flags.tvout)
1492 					continue;
1493 				break;
1494 			case ACPI_VIDEO_DISPLAY_DVI:
1495 				if (!video_device->flags.dvi)
1496 					continue;
1497 				break;
1498 			case ACPI_VIDEO_DISPLAY_LCD:
1499 				if (!video_device->flags.lcd)
1500 					continue;
1501 				break;
1502 			}
1503 		} else if (video_device->device_id != device_id) {
1504 			continue;
1505 		}
1506 
1507 		status = acpi_video_device_EDID(video_device, &buffer, length);
1508 
1509 		if (ACPI_FAILURE(status) || !buffer ||
1510 		    buffer->type != ACPI_TYPE_BUFFER) {
1511 			length = 128;
1512 			status = acpi_video_device_EDID(video_device, &buffer,
1513 							length);
1514 			if (ACPI_FAILURE(status) || !buffer ||
1515 			    buffer->type != ACPI_TYPE_BUFFER) {
1516 				continue;
1517 			}
1518 		}
1519 
1520 		*edid = buffer->buffer.pointer;
1521 		return length;
1522 	}
1523 
1524 	return -ENODEV;
1525 }
1526 EXPORT_SYMBOL(acpi_video_get_edid);
1527 
1528 static int
1529 acpi_video_bus_get_devices(struct acpi_video_bus *video,
1530 			   struct acpi_device *device)
1531 {
1532 	int status = 0;
1533 	struct acpi_device *dev;
1534 
1535 	/*
1536 	 * There are systems where video module known to work fine regardless
1537 	 * of broken _DOD and ignoring returned value here doesn't cause
1538 	 * any issues later.
1539 	 */
1540 	acpi_video_device_enumerate(video);
1541 
1542 	list_for_each_entry(dev, &device->children, node) {
1543 
1544 		status = acpi_video_bus_get_one_device(dev, video);
1545 		if (status) {
1546 			dev_err(&dev->dev, "Can't attach device\n");
1547 			break;
1548 		}
1549 		video->child_count++;
1550 	}
1551 	return status;
1552 }
1553 
1554 /* acpi_video interface */
1555 
1556 /*
1557  * Win8 requires setting bit2 of _DOS to let firmware know it shouldn't
1558  * perform any automatic brightness change on receiving a notification.
1559  */
1560 static int acpi_video_bus_start_devices(struct acpi_video_bus *video)
1561 {
1562 	return acpi_video_bus_DOS(video, 0,
1563 				  acpi_osi_is_win8() ? 1 : 0);
1564 }
1565 
1566 static int acpi_video_bus_stop_devices(struct acpi_video_bus *video)
1567 {
1568 	return acpi_video_bus_DOS(video, 0,
1569 				  acpi_osi_is_win8() ? 0 : 1);
1570 }
1571 
1572 static void acpi_video_bus_notify(struct acpi_device *device, u32 event)
1573 {
1574 	struct acpi_video_bus *video = acpi_driver_data(device);
1575 	struct input_dev *input;
1576 	int keycode = 0;
1577 
1578 	if (!video || !video->input)
1579 		return;
1580 
1581 	input = video->input;
1582 
1583 	switch (event) {
1584 	case ACPI_VIDEO_NOTIFY_SWITCH:	/* User requested a switch,
1585 					 * most likely via hotkey. */
1586 		keycode = KEY_SWITCHVIDEOMODE;
1587 		break;
1588 
1589 	case ACPI_VIDEO_NOTIFY_PROBE:	/* User plugged in or removed a video
1590 					 * connector. */
1591 		acpi_video_device_enumerate(video);
1592 		acpi_video_device_rebind(video);
1593 		keycode = KEY_SWITCHVIDEOMODE;
1594 		break;
1595 
1596 	case ACPI_VIDEO_NOTIFY_CYCLE:	/* Cycle Display output hotkey pressed. */
1597 		keycode = KEY_SWITCHVIDEOMODE;
1598 		break;
1599 	case ACPI_VIDEO_NOTIFY_NEXT_OUTPUT:	/* Next Display output hotkey pressed. */
1600 		keycode = KEY_VIDEO_NEXT;
1601 		break;
1602 	case ACPI_VIDEO_NOTIFY_PREV_OUTPUT:	/* previous Display output hotkey pressed. */
1603 		keycode = KEY_VIDEO_PREV;
1604 		break;
1605 
1606 	default:
1607 		acpi_handle_debug(device->handle, "Unsupported event [0x%x]\n",
1608 				  event);
1609 		break;
1610 	}
1611 
1612 	if (acpi_notifier_call_chain(device, event, 0))
1613 		/* Something vetoed the keypress. */
1614 		keycode = 0;
1615 
1616 	if (keycode && (report_key_events & REPORT_OUTPUT_KEY_EVENTS)) {
1617 		input_report_key(input, keycode, 1);
1618 		input_sync(input);
1619 		input_report_key(input, keycode, 0);
1620 		input_sync(input);
1621 	}
1622 
1623 	return;
1624 }
1625 
1626 static void brightness_switch_event(struct acpi_video_device *video_device,
1627 				    u32 event)
1628 {
1629 	if (!brightness_switch_enabled)
1630 		return;
1631 
1632 	video_device->switch_brightness_event = event;
1633 	schedule_delayed_work(&video_device->switch_brightness_work, HZ / 10);
1634 }
1635 
1636 static void acpi_video_device_notify(acpi_handle handle, u32 event, void *data)
1637 {
1638 	struct acpi_video_device *video_device = data;
1639 	struct acpi_device *device = NULL;
1640 	struct acpi_video_bus *bus;
1641 	struct input_dev *input;
1642 	int keycode = 0;
1643 
1644 	if (!video_device)
1645 		return;
1646 
1647 	device = video_device->dev;
1648 	bus = video_device->video;
1649 	input = bus->input;
1650 
1651 	if (hw_changes_brightness > 0) {
1652 		if (video_device->backlight)
1653 			backlight_force_update(video_device->backlight,
1654 					       BACKLIGHT_UPDATE_HOTKEY);
1655 		acpi_notifier_call_chain(device, event, 0);
1656 		return;
1657 	}
1658 
1659 	switch (event) {
1660 	case ACPI_VIDEO_NOTIFY_CYCLE_BRIGHTNESS:	/* Cycle brightness */
1661 		brightness_switch_event(video_device, event);
1662 		keycode = KEY_BRIGHTNESS_CYCLE;
1663 		break;
1664 	case ACPI_VIDEO_NOTIFY_INC_BRIGHTNESS:	/* Increase brightness */
1665 		brightness_switch_event(video_device, event);
1666 		keycode = KEY_BRIGHTNESSUP;
1667 		break;
1668 	case ACPI_VIDEO_NOTIFY_DEC_BRIGHTNESS:	/* Decrease brightness */
1669 		brightness_switch_event(video_device, event);
1670 		keycode = KEY_BRIGHTNESSDOWN;
1671 		break;
1672 	case ACPI_VIDEO_NOTIFY_ZERO_BRIGHTNESS:	/* zero brightness */
1673 		brightness_switch_event(video_device, event);
1674 		keycode = KEY_BRIGHTNESS_ZERO;
1675 		break;
1676 	case ACPI_VIDEO_NOTIFY_DISPLAY_OFF:	/* display device off */
1677 		brightness_switch_event(video_device, event);
1678 		keycode = KEY_DISPLAY_OFF;
1679 		break;
1680 	default:
1681 		acpi_handle_debug(handle, "Unsupported event [0x%x]\n", event);
1682 		break;
1683 	}
1684 
1685 	acpi_notifier_call_chain(device, event, 0);
1686 
1687 	if (keycode && (report_key_events & REPORT_BRIGHTNESS_KEY_EVENTS)) {
1688 		input_report_key(input, keycode, 1);
1689 		input_sync(input);
1690 		input_report_key(input, keycode, 0);
1691 		input_sync(input);
1692 	}
1693 
1694 	return;
1695 }
1696 
1697 static int acpi_video_resume(struct notifier_block *nb,
1698 				unsigned long val, void *ign)
1699 {
1700 	struct acpi_video_bus *video;
1701 	struct acpi_video_device *video_device;
1702 	int i;
1703 
1704 	switch (val) {
1705 	case PM_HIBERNATION_PREPARE:
1706 	case PM_SUSPEND_PREPARE:
1707 	case PM_RESTORE_PREPARE:
1708 		return NOTIFY_DONE;
1709 	}
1710 
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 
1725 static acpi_status
1726 acpi_video_bus_match(acpi_handle handle, u32 level, void *context,
1727 			void **return_value)
1728 {
1729 	struct acpi_device *device = context;
1730 	struct acpi_device *sibling;
1731 	int result;
1732 
1733 	if (handle == device->handle)
1734 		return AE_CTRL_TERMINATE;
1735 
1736 	result = acpi_bus_get_device(handle, &sibling);
1737 	if (result)
1738 		return AE_OK;
1739 
1740 	if (!strcmp(acpi_device_name(sibling), ACPI_VIDEO_BUS_NAME))
1741 			return AE_ALREADY_EXISTS;
1742 
1743 	return AE_OK;
1744 }
1745 
1746 static void acpi_video_dev_register_backlight(struct acpi_video_device *device)
1747 {
1748 	struct backlight_properties props;
1749 	struct pci_dev *pdev;
1750 	acpi_handle acpi_parent;
1751 	struct device *parent = NULL;
1752 	int result;
1753 	static int count;
1754 	char *name;
1755 
1756 	result = acpi_video_init_brightness(device);
1757 	if (result)
1758 		return;
1759 
1760 	if (disable_backlight_sysfs_if > 0)
1761 		return;
1762 
1763 	name = kasprintf(GFP_KERNEL, "acpi_video%d", count);
1764 	if (!name)
1765 		return;
1766 	count++;
1767 
1768 	acpi_get_parent(device->dev->handle, &acpi_parent);
1769 
1770 	pdev = acpi_get_pci_dev(acpi_parent);
1771 	if (pdev) {
1772 		parent = &pdev->dev;
1773 		pci_dev_put(pdev);
1774 	}
1775 
1776 	memset(&props, 0, sizeof(struct backlight_properties));
1777 	props.type = BACKLIGHT_FIRMWARE;
1778 	props.max_brightness =
1779 		device->brightness->count - ACPI_VIDEO_FIRST_LEVEL - 1;
1780 	device->backlight = backlight_device_register(name,
1781 						      parent,
1782 						      device,
1783 						      &acpi_backlight_ops,
1784 						      &props);
1785 	kfree(name);
1786 	if (IS_ERR(device->backlight)) {
1787 		device->backlight = NULL;
1788 		return;
1789 	}
1790 
1791 	/*
1792 	 * Save current brightness level in case we have to restore it
1793 	 * before acpi_video_device_lcd_set_level() is called next time.
1794 	 */
1795 	device->backlight->props.brightness =
1796 			acpi_video_get_brightness(device->backlight);
1797 
1798 	device->cooling_dev = thermal_cooling_device_register("LCD",
1799 				device->dev, &video_cooling_ops);
1800 	if (IS_ERR(device->cooling_dev)) {
1801 		/*
1802 		 * Set cooling_dev to NULL so we don't crash trying to free it.
1803 		 * Also, why the hell we are returning early and not attempt to
1804 		 * register video output if cooling device registration failed?
1805 		 * -- dtor
1806 		 */
1807 		device->cooling_dev = NULL;
1808 		return;
1809 	}
1810 
1811 	dev_info(&device->dev->dev, "registered as cooling_device%d\n",
1812 		 device->cooling_dev->id);
1813 	result = sysfs_create_link(&device->dev->dev.kobj,
1814 			&device->cooling_dev->device.kobj,
1815 			"thermal_cooling");
1816 	if (result)
1817 		pr_info("sysfs link creation failed\n");
1818 
1819 	result = sysfs_create_link(&device->cooling_dev->device.kobj,
1820 			&device->dev->dev.kobj, "device");
1821 	if (result)
1822 		pr_info("Reverse sysfs link creation failed\n");
1823 }
1824 
1825 static void acpi_video_run_bcl_for_osi(struct acpi_video_bus *video)
1826 {
1827 	struct acpi_video_device *dev;
1828 	union acpi_object *levels;
1829 
1830 	mutex_lock(&video->device_list_lock);
1831 	list_for_each_entry(dev, &video->video_device_list, entry) {
1832 		if (!acpi_video_device_lcd_query_levels(dev->dev->handle, &levels))
1833 			kfree(levels);
1834 	}
1835 	mutex_unlock(&video->device_list_lock);
1836 }
1837 
1838 static bool acpi_video_should_register_backlight(struct acpi_video_device *dev)
1839 {
1840 	/*
1841 	 * Do not create backlight device for video output
1842 	 * device that is not in the enumerated list.
1843 	 */
1844 	if (!acpi_video_device_in_dod(dev)) {
1845 		dev_dbg(&dev->dev->dev, "not in _DOD list, ignore\n");
1846 		return false;
1847 	}
1848 
1849 	if (only_lcd)
1850 		return dev->flags.lcd;
1851 	return true;
1852 }
1853 
1854 static int acpi_video_bus_register_backlight(struct acpi_video_bus *video)
1855 {
1856 	struct acpi_video_device *dev;
1857 
1858 	if (video->backlight_registered)
1859 		return 0;
1860 
1861 	acpi_video_run_bcl_for_osi(video);
1862 
1863 	if (acpi_video_get_backlight_type() != acpi_backlight_video)
1864 		return 0;
1865 
1866 	mutex_lock(&video->device_list_lock);
1867 	list_for_each_entry(dev, &video->video_device_list, entry) {
1868 		if (acpi_video_should_register_backlight(dev))
1869 			acpi_video_dev_register_backlight(dev);
1870 	}
1871 	mutex_unlock(&video->device_list_lock);
1872 
1873 	video->backlight_registered = true;
1874 
1875 	video->pm_nb.notifier_call = acpi_video_resume;
1876 	video->pm_nb.priority = 0;
1877 	return register_pm_notifier(&video->pm_nb);
1878 }
1879 
1880 static void acpi_video_dev_unregister_backlight(struct acpi_video_device *device)
1881 {
1882 	if (device->backlight) {
1883 		backlight_device_unregister(device->backlight);
1884 		device->backlight = NULL;
1885 	}
1886 	if (device->brightness) {
1887 		kfree(device->brightness->levels);
1888 		kfree(device->brightness);
1889 		device->brightness = NULL;
1890 	}
1891 	if (device->cooling_dev) {
1892 		sysfs_remove_link(&device->dev->dev.kobj, "thermal_cooling");
1893 		sysfs_remove_link(&device->cooling_dev->device.kobj, "device");
1894 		thermal_cooling_device_unregister(device->cooling_dev);
1895 		device->cooling_dev = NULL;
1896 	}
1897 }
1898 
1899 static int acpi_video_bus_unregister_backlight(struct acpi_video_bus *video)
1900 {
1901 	struct acpi_video_device *dev;
1902 	int error;
1903 
1904 	if (!video->backlight_registered)
1905 		return 0;
1906 
1907 	error = unregister_pm_notifier(&video->pm_nb);
1908 
1909 	mutex_lock(&video->device_list_lock);
1910 	list_for_each_entry(dev, &video->video_device_list, entry)
1911 		acpi_video_dev_unregister_backlight(dev);
1912 	mutex_unlock(&video->device_list_lock);
1913 
1914 	video->backlight_registered = false;
1915 
1916 	return error;
1917 }
1918 
1919 static void acpi_video_dev_add_notify_handler(struct acpi_video_device *device)
1920 {
1921 	acpi_status status;
1922 	struct acpi_device *adev = device->dev;
1923 
1924 	status = acpi_install_notify_handler(adev->handle, ACPI_DEVICE_NOTIFY,
1925 					     acpi_video_device_notify, device);
1926 	if (ACPI_FAILURE(status))
1927 		dev_err(&adev->dev, "Error installing notify handler\n");
1928 	else
1929 		device->flags.notify = 1;
1930 }
1931 
1932 static int acpi_video_bus_add_notify_handler(struct acpi_video_bus *video)
1933 {
1934 	struct input_dev *input;
1935 	struct acpi_video_device *dev;
1936 	int error;
1937 
1938 	video->input = input = input_allocate_device();
1939 	if (!input) {
1940 		error = -ENOMEM;
1941 		goto out;
1942 	}
1943 
1944 	error = acpi_video_bus_start_devices(video);
1945 	if (error)
1946 		goto err_free_input;
1947 
1948 	snprintf(video->phys, sizeof(video->phys),
1949 			"%s/video/input0", acpi_device_hid(video->device));
1950 
1951 	input->name = acpi_device_name(video->device);
1952 	input->phys = video->phys;
1953 	input->id.bustype = BUS_HOST;
1954 	input->id.product = 0x06;
1955 	input->dev.parent = &video->device->dev;
1956 	input->evbit[0] = BIT(EV_KEY);
1957 	set_bit(KEY_SWITCHVIDEOMODE, input->keybit);
1958 	set_bit(KEY_VIDEO_NEXT, input->keybit);
1959 	set_bit(KEY_VIDEO_PREV, input->keybit);
1960 	set_bit(KEY_BRIGHTNESS_CYCLE, input->keybit);
1961 	set_bit(KEY_BRIGHTNESSUP, input->keybit);
1962 	set_bit(KEY_BRIGHTNESSDOWN, input->keybit);
1963 	set_bit(KEY_BRIGHTNESS_ZERO, input->keybit);
1964 	set_bit(KEY_DISPLAY_OFF, input->keybit);
1965 
1966 	error = input_register_device(input);
1967 	if (error)
1968 		goto err_stop_dev;
1969 
1970 	mutex_lock(&video->device_list_lock);
1971 	list_for_each_entry(dev, &video->video_device_list, entry)
1972 		acpi_video_dev_add_notify_handler(dev);
1973 	mutex_unlock(&video->device_list_lock);
1974 
1975 	return 0;
1976 
1977 err_stop_dev:
1978 	acpi_video_bus_stop_devices(video);
1979 err_free_input:
1980 	input_free_device(input);
1981 	video->input = NULL;
1982 out:
1983 	return error;
1984 }
1985 
1986 static void acpi_video_dev_remove_notify_handler(struct acpi_video_device *dev)
1987 {
1988 	if (dev->flags.notify) {
1989 		acpi_remove_notify_handler(dev->dev->handle, ACPI_DEVICE_NOTIFY,
1990 					   acpi_video_device_notify);
1991 		dev->flags.notify = 0;
1992 	}
1993 }
1994 
1995 static void acpi_video_bus_remove_notify_handler(struct acpi_video_bus *video)
1996 {
1997 	struct acpi_video_device *dev;
1998 
1999 	mutex_lock(&video->device_list_lock);
2000 	list_for_each_entry(dev, &video->video_device_list, entry)
2001 		acpi_video_dev_remove_notify_handler(dev);
2002 	mutex_unlock(&video->device_list_lock);
2003 
2004 	acpi_video_bus_stop_devices(video);
2005 	input_unregister_device(video->input);
2006 	video->input = NULL;
2007 }
2008 
2009 static int acpi_video_bus_put_devices(struct acpi_video_bus *video)
2010 {
2011 	struct acpi_video_device *dev, *next;
2012 
2013 	mutex_lock(&video->device_list_lock);
2014 	list_for_each_entry_safe(dev, next, &video->video_device_list, entry) {
2015 		list_del(&dev->entry);
2016 		kfree(dev);
2017 	}
2018 	mutex_unlock(&video->device_list_lock);
2019 
2020 	return 0;
2021 }
2022 
2023 static int instance;
2024 
2025 static int acpi_video_bus_add(struct acpi_device *device)
2026 {
2027 	struct acpi_video_bus *video;
2028 	int error;
2029 	acpi_status status;
2030 
2031 	status = acpi_walk_namespace(ACPI_TYPE_DEVICE,
2032 				device->parent->handle, 1,
2033 				acpi_video_bus_match, NULL,
2034 				device, NULL);
2035 	if (status == AE_ALREADY_EXISTS) {
2036 		pr_info(FW_BUG
2037 			"Duplicate ACPI video bus devices for the"
2038 			" same VGA controller, please try module "
2039 			"parameter \"video.allow_duplicates=1\""
2040 			"if the current driver doesn't work.\n");
2041 		if (!allow_duplicates)
2042 			return -ENODEV;
2043 	}
2044 
2045 	video = kzalloc(sizeof(struct acpi_video_bus), GFP_KERNEL);
2046 	if (!video)
2047 		return -ENOMEM;
2048 
2049 	/* a hack to fix the duplicate name "VID" problem on T61 */
2050 	if (!strcmp(device->pnp.bus_id, "VID")) {
2051 		if (instance)
2052 			device->pnp.bus_id[3] = '0' + instance;
2053 		instance++;
2054 	}
2055 	/* a hack to fix the duplicate name "VGA" problem on Pa 3553 */
2056 	if (!strcmp(device->pnp.bus_id, "VGA")) {
2057 		if (instance)
2058 			device->pnp.bus_id[3] = '0' + instance;
2059 		instance++;
2060 	}
2061 
2062 	video->device = device;
2063 	strcpy(acpi_device_name(device), ACPI_VIDEO_BUS_NAME);
2064 	strcpy(acpi_device_class(device), ACPI_VIDEO_CLASS);
2065 	device->driver_data = video;
2066 
2067 	acpi_video_bus_find_cap(video);
2068 	error = acpi_video_bus_check(video);
2069 	if (error)
2070 		goto err_free_video;
2071 
2072 	mutex_init(&video->device_list_lock);
2073 	INIT_LIST_HEAD(&video->video_device_list);
2074 
2075 	error = acpi_video_bus_get_devices(video, device);
2076 	if (error)
2077 		goto err_put_video;
2078 
2079 	pr_info("%s [%s] (multi-head: %s  rom: %s  post: %s)\n",
2080 	       ACPI_VIDEO_DEVICE_NAME, acpi_device_bid(device),
2081 	       video->flags.multihead ? "yes" : "no",
2082 	       video->flags.rom ? "yes" : "no",
2083 	       video->flags.post ? "yes" : "no");
2084 	mutex_lock(&video_list_lock);
2085 	list_add_tail(&video->entry, &video_bus_head);
2086 	mutex_unlock(&video_list_lock);
2087 
2088 	acpi_video_bus_register_backlight(video);
2089 	acpi_video_bus_add_notify_handler(video);
2090 
2091 	return 0;
2092 
2093 err_put_video:
2094 	acpi_video_bus_put_devices(video);
2095 	kfree(video->attached_array);
2096 err_free_video:
2097 	kfree(video);
2098 	device->driver_data = NULL;
2099 
2100 	return error;
2101 }
2102 
2103 static int acpi_video_bus_remove(struct acpi_device *device)
2104 {
2105 	struct acpi_video_bus *video = NULL;
2106 
2107 
2108 	if (!device || !acpi_driver_data(device))
2109 		return -EINVAL;
2110 
2111 	video = acpi_driver_data(device);
2112 
2113 	acpi_video_bus_remove_notify_handler(video);
2114 	acpi_video_bus_unregister_backlight(video);
2115 	acpi_video_bus_put_devices(video);
2116 
2117 	mutex_lock(&video_list_lock);
2118 	list_del(&video->entry);
2119 	mutex_unlock(&video_list_lock);
2120 
2121 	kfree(video->attached_array);
2122 	kfree(video);
2123 
2124 	return 0;
2125 }
2126 
2127 static int __init is_i740(struct pci_dev *dev)
2128 {
2129 	if (dev->device == 0x00D1)
2130 		return 1;
2131 	if (dev->device == 0x7000)
2132 		return 1;
2133 	return 0;
2134 }
2135 
2136 static int __init intel_opregion_present(void)
2137 {
2138 	int opregion = 0;
2139 	struct pci_dev *dev = NULL;
2140 	u32 address;
2141 
2142 	for_each_pci_dev(dev) {
2143 		if ((dev->class >> 8) != PCI_CLASS_DISPLAY_VGA)
2144 			continue;
2145 		if (dev->vendor != PCI_VENDOR_ID_INTEL)
2146 			continue;
2147 		/* We don't want to poke around undefined i740 registers */
2148 		if (is_i740(dev))
2149 			continue;
2150 		pci_read_config_dword(dev, 0xfc, &address);
2151 		if (!address)
2152 			continue;
2153 		opregion = 1;
2154 	}
2155 	return opregion;
2156 }
2157 
2158 /* Check if the chassis-type indicates there is no builtin LCD panel */
2159 static bool dmi_is_desktop(void)
2160 {
2161 	const char *chassis_type;
2162 	unsigned long type;
2163 
2164 	chassis_type = dmi_get_system_info(DMI_CHASSIS_TYPE);
2165 	if (!chassis_type)
2166 		return false;
2167 
2168 	if (kstrtoul(chassis_type, 10, &type) != 0)
2169 		return false;
2170 
2171 	switch (type) {
2172 	case 0x03: /* Desktop */
2173 	case 0x04: /* Low Profile Desktop */
2174 	case 0x05: /* Pizza Box */
2175 	case 0x06: /* Mini Tower */
2176 	case 0x07: /* Tower */
2177 	case 0x10: /* Lunch Box */
2178 	case 0x11: /* Main Server Chassis */
2179 		return true;
2180 	}
2181 
2182 	return false;
2183 }
2184 
2185 /*
2186  * We're seeing a lot of bogus backlight interfaces on newer machines
2187  * without a LCD such as desktops, servers and HDMI sticks. Checking the
2188  * lcd flag fixes this, enable this by default on any machines which are:
2189  * 1.  Win8 ready (where we also prefer the native backlight driver, so
2190  *     normally the acpi_video code should not register there anyways); *and*
2191  * 2.1 Report a desktop/server DMI chassis-type, or
2192  * 2.2 Are an ACPI-reduced-hardware platform (and thus won't use the EC for
2193        backlight control)
2194  */
2195 static bool should_check_lcd_flag(void)
2196 {
2197 	if (!acpi_osi_is_win8())
2198 		return false;
2199 
2200 	if (dmi_is_desktop())
2201 		return true;
2202 
2203 	if (acpi_reduced_hardware())
2204 		return true;
2205 
2206 	return false;
2207 }
2208 
2209 int acpi_video_register(void)
2210 {
2211 	int ret = 0;
2212 
2213 	mutex_lock(&register_count_mutex);
2214 	if (register_count) {
2215 		/*
2216 		 * if the function of acpi_video_register is already called,
2217 		 * don't register the acpi_video_bus again and return no error.
2218 		 */
2219 		goto leave;
2220 	}
2221 
2222 	if (only_lcd == -1)
2223 		only_lcd = should_check_lcd_flag();
2224 
2225 	dmi_check_system(video_dmi_table);
2226 
2227 	ret = acpi_bus_register_driver(&acpi_video_bus);
2228 	if (ret)
2229 		goto leave;
2230 
2231 	/*
2232 	 * When the acpi_video_bus is loaded successfully, increase
2233 	 * the counter reference.
2234 	 */
2235 	register_count = 1;
2236 
2237 leave:
2238 	mutex_unlock(&register_count_mutex);
2239 	return ret;
2240 }
2241 EXPORT_SYMBOL(acpi_video_register);
2242 
2243 void acpi_video_unregister(void)
2244 {
2245 	mutex_lock(&register_count_mutex);
2246 	if (register_count) {
2247 		acpi_bus_unregister_driver(&acpi_video_bus);
2248 		register_count = 0;
2249 	}
2250 	mutex_unlock(&register_count_mutex);
2251 }
2252 EXPORT_SYMBOL(acpi_video_unregister);
2253 
2254 void acpi_video_unregister_backlight(void)
2255 {
2256 	struct acpi_video_bus *video;
2257 
2258 	mutex_lock(&register_count_mutex);
2259 	if (register_count) {
2260 		mutex_lock(&video_list_lock);
2261 		list_for_each_entry(video, &video_bus_head, entry)
2262 			acpi_video_bus_unregister_backlight(video);
2263 		mutex_unlock(&video_list_lock);
2264 	}
2265 	mutex_unlock(&register_count_mutex);
2266 }
2267 
2268 bool acpi_video_handles_brightness_key_presses(void)
2269 {
2270 	bool have_video_busses;
2271 
2272 	mutex_lock(&video_list_lock);
2273 	have_video_busses = !list_empty(&video_bus_head);
2274 	mutex_unlock(&video_list_lock);
2275 
2276 	return have_video_busses &&
2277 	       (report_key_events & REPORT_BRIGHTNESS_KEY_EVENTS);
2278 }
2279 EXPORT_SYMBOL(acpi_video_handles_brightness_key_presses);
2280 
2281 /*
2282  * This is kind of nasty. Hardware using Intel chipsets may require
2283  * the video opregion code to be run first in order to initialise
2284  * state before any ACPI video calls are made. To handle this we defer
2285  * registration of the video class until the opregion code has run.
2286  */
2287 
2288 static int __init acpi_video_init(void)
2289 {
2290 	/*
2291 	 * Let the module load even if ACPI is disabled (e.g. due to
2292 	 * a broken BIOS) so that i915.ko can still be loaded on such
2293 	 * old systems without an AcpiOpRegion.
2294 	 *
2295 	 * acpi_video_register() will report -ENODEV later as well due
2296 	 * to acpi_disabled when i915.ko tries to register itself afterwards.
2297 	 */
2298 	if (acpi_disabled)
2299 		return 0;
2300 
2301 	if (intel_opregion_present())
2302 		return 0;
2303 
2304 	return acpi_video_register();
2305 }
2306 
2307 static void __exit acpi_video_exit(void)
2308 {
2309 	acpi_video_detect_exit();
2310 	acpi_video_unregister();
2311 
2312 	return;
2313 }
2314 
2315 module_init(acpi_video_init);
2316 module_exit(acpi_video_exit);
2317