xref: /openbmc/linux/drivers/acpi/acpi_video.c (revision de528723)
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 the power changes from AC to DC
703  *		1.	The system BIOS should NOT automatically control the brightness
704  *			level of the LCD when the power changes from AC to DC.
705  *  Return Value:
706  *		-EINVAL	wrong arg.
707  */
708 
709 static int
710 acpi_video_bus_DOS(struct acpi_video_bus *video, int bios_flag, int lcd_flag)
711 {
712 	acpi_status status;
713 
714 	if (!video->cap._DOS)
715 		return 0;
716 
717 	if (bios_flag < 0 || bios_flag > 3 || lcd_flag < 0 || lcd_flag > 1)
718 		return -EINVAL;
719 	video->dos_setting = (lcd_flag << 2) | bios_flag;
720 	status = acpi_execute_simple_method(video->device->handle, "_DOS",
721 					    (lcd_flag << 2) | bios_flag);
722 	if (ACPI_FAILURE(status))
723 		return -EIO;
724 
725 	return 0;
726 }
727 
728 /*
729  * Simple comparison function used to sort backlight levels.
730  */
731 
732 static int
733 acpi_video_cmp_level(const void *a, const void *b)
734 {
735 	return *(int *)a - *(int *)b;
736 }
737 
738 /*
739  * Decides if _BQC/_BCQ for this system is usable
740  *
741  * We do this by changing the level first and then read out the current
742  * brightness level, if the value does not match, find out if it is using
743  * index. If not, clear the _BQC/_BCQ capability.
744  */
745 static int acpi_video_bqc_quirk(struct acpi_video_device *device,
746 				int max_level, int current_level)
747 {
748 	struct acpi_video_device_brightness *br = device->brightness;
749 	int result;
750 	unsigned long long level;
751 	int test_level;
752 
753 	/* don't mess with existing known broken systems */
754 	if (bqc_offset_aml_bug_workaround)
755 		return 0;
756 
757 	/*
758 	 * Some systems always report current brightness level as maximum
759 	 * through _BQC, we need to test another value for them. However,
760 	 * there is a subtlety:
761 	 *
762 	 * If the _BCL package ordering is descending, the first level
763 	 * (br->levels[2]) is likely to be 0, and if the number of levels
764 	 * matches the number of steps, we might confuse a returned level to
765 	 * mean the index.
766 	 *
767 	 * For example:
768 	 *
769 	 *     current_level = max_level = 100
770 	 *     test_level = 0
771 	 *     returned level = 100
772 	 *
773 	 * In this case 100 means the level, not the index, and _BCM failed.
774 	 * Still, if the _BCL package ordering is descending, the index of
775 	 * level 0 is also 100, so we assume _BQC is indexed, when it's not.
776 	 *
777 	 * This causes all _BQC calls to return bogus values causing weird
778 	 * behavior from the user's perspective.  For example:
779 	 *
780 	 * xbacklight -set 10; xbacklight -set 20;
781 	 *
782 	 * would flash to 90% and then slowly down to the desired level (20).
783 	 *
784 	 * The solution is simple; test anything other than the first level
785 	 * (e.g. 1).
786 	 */
787 	test_level = current_level == max_level
788 		? br->levels[ACPI_VIDEO_FIRST_LEVEL + 1]
789 		: max_level;
790 
791 	result = acpi_video_device_lcd_set_level(device, test_level);
792 	if (result)
793 		return result;
794 
795 	result = acpi_video_device_lcd_get_level_current(device, &level, true);
796 	if (result)
797 		return result;
798 
799 	if (level != test_level) {
800 		/* buggy _BQC found, need to find out if it uses index */
801 		if (level < br->count) {
802 			if (br->flags._BCL_reversed)
803 				level = br->count - ACPI_VIDEO_FIRST_LEVEL - 1 - level;
804 			if (br->levels[level + ACPI_VIDEO_FIRST_LEVEL] == test_level)
805 				br->flags._BQC_use_index = 1;
806 		}
807 
808 		if (!br->flags._BQC_use_index)
809 			device->cap._BQC = device->cap._BCQ = 0;
810 	}
811 
812 	return 0;
813 }
814 
815 int acpi_video_get_levels(struct acpi_device *device,
816 			  struct acpi_video_device_brightness **dev_br,
817 			  int *pmax_level)
818 {
819 	union acpi_object *obj = NULL;
820 	int i, max_level = 0, count = 0, level_ac_battery = 0;
821 	union acpi_object *o;
822 	struct acpi_video_device_brightness *br = NULL;
823 	int result = 0;
824 	u32 value;
825 
826 	if (!ACPI_SUCCESS(acpi_video_device_lcd_query_levels(device->handle,
827 								&obj))) {
828 		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Could not query available "
829 						"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 		printk(KERN_ERR "can't allocate memory\n");
842 		result = -ENOMEM;
843 		goto out;
844 	}
845 
846 	/*
847 	 * Note that we have to reserve 2 extra items (ACPI_VIDEO_FIRST_LEVEL),
848 	 * in order to account for buggy BIOS which don't export the first two
849 	 * special levels (see below)
850 	 */
851 	br->levels = kmalloc_array(obj->package.count + ACPI_VIDEO_FIRST_LEVEL,
852 				   sizeof(*br->levels),
853 				   GFP_KERNEL);
854 	if (!br->levels) {
855 		result = -ENOMEM;
856 		goto out_free;
857 	}
858 
859 	for (i = 0; i < obj->package.count; i++) {
860 		o = (union acpi_object *)&obj->package.elements[i];
861 		if (o->type != ACPI_TYPE_INTEGER) {
862 			printk(KERN_ERR PREFIX "Invalid data\n");
863 			continue;
864 		}
865 		value = (u32) o->integer.value;
866 		/* Skip duplicate entries */
867 		if (count > ACPI_VIDEO_FIRST_LEVEL
868 		    && br->levels[count - 1] == value)
869 			continue;
870 
871 		br->levels[count] = value;
872 
873 		if (br->levels[count] > max_level)
874 			max_level = br->levels[count];
875 		count++;
876 	}
877 
878 	/*
879 	 * some buggy BIOS don't export the levels
880 	 * when machine is on AC/Battery in _BCL package.
881 	 * In this case, the first two elements in _BCL packages
882 	 * are also supported brightness levels that OS should take care of.
883 	 */
884 	for (i = ACPI_VIDEO_FIRST_LEVEL; i < count; i++) {
885 		if (br->levels[i] == br->levels[ACPI_VIDEO_AC_LEVEL])
886 			level_ac_battery++;
887 		if (br->levels[i] == br->levels[ACPI_VIDEO_BATTERY_LEVEL])
888 			level_ac_battery++;
889 	}
890 
891 	if (level_ac_battery < ACPI_VIDEO_FIRST_LEVEL) {
892 		level_ac_battery = ACPI_VIDEO_FIRST_LEVEL - level_ac_battery;
893 		br->flags._BCL_no_ac_battery_levels = 1;
894 		for (i = (count - 1 + level_ac_battery);
895 		     i >= ACPI_VIDEO_FIRST_LEVEL; i--)
896 			br->levels[i] = br->levels[i - level_ac_battery];
897 		count += level_ac_battery;
898 	} else if (level_ac_battery > ACPI_VIDEO_FIRST_LEVEL)
899 		ACPI_ERROR((AE_INFO, "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_ERROR((AE_INFO,
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 = -EINVAL;
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_DEBUG_PRINT((ACPI_DB_INFO,
989 	                  "found %d brightness levels\n",
990 	                  br->count - ACPI_VIDEO_FIRST_LEVEL));
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 		printk(KERN_WARNING FW_BUG "_BCQ is used instead of _BQC\n");
1023 		device->cap._BCQ = 1;
1024 	}
1025 
1026 	if (acpi_has_method(device->dev->handle, "_DDC"))
1027 		device->cap._DDC = 1;
1028 }
1029 
1030 /*
1031  *  Arg:
1032  *	device	: video output device (VGA)
1033  *
1034  *  Return Value:
1035  *	None
1036  *
1037  *  Find out all required AML methods defined under the video bus device.
1038  */
1039 
1040 static void acpi_video_bus_find_cap(struct acpi_video_bus *video)
1041 {
1042 	if (acpi_has_method(video->device->handle, "_DOS"))
1043 		video->cap._DOS = 1;
1044 	if (acpi_has_method(video->device->handle, "_DOD"))
1045 		video->cap._DOD = 1;
1046 	if (acpi_has_method(video->device->handle, "_ROM"))
1047 		video->cap._ROM = 1;
1048 	if (acpi_has_method(video->device->handle, "_GPD"))
1049 		video->cap._GPD = 1;
1050 	if (acpi_has_method(video->device->handle, "_SPD"))
1051 		video->cap._SPD = 1;
1052 	if (acpi_has_method(video->device->handle, "_VPO"))
1053 		video->cap._VPO = 1;
1054 }
1055 
1056 /*
1057  * Check whether the video bus device has required AML method to
1058  * support the desired features
1059  */
1060 
1061 static int acpi_video_bus_check(struct acpi_video_bus *video)
1062 {
1063 	acpi_status status = -ENOENT;
1064 	struct pci_dev *dev;
1065 
1066 	if (!video)
1067 		return -EINVAL;
1068 
1069 	dev = acpi_get_pci_dev(video->device->handle);
1070 	if (!dev)
1071 		return -ENODEV;
1072 	pci_dev_put(dev);
1073 
1074 	/*
1075 	 * Since there is no HID, CID and so on for VGA driver, we have
1076 	 * to check well known required nodes.
1077 	 */
1078 
1079 	/* Does this device support video switching? */
1080 	if (video->cap._DOS || video->cap._DOD) {
1081 		if (!video->cap._DOS) {
1082 			printk(KERN_WARNING FW_BUG
1083 				"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_DEBUG_PRINT((ACPI_DB_INFO, "device_bind %d\n", i));
1272 		}
1273 	}
1274 }
1275 
1276 static bool acpi_video_device_in_dod(struct acpi_video_device *device)
1277 {
1278 	struct acpi_video_bus *video = device->video;
1279 	int i;
1280 
1281 	/*
1282 	 * If we have a broken _DOD or we have more than 8 output devices
1283 	 * under the graphics controller node that we can't proper deal with
1284 	 * in the operation region code currently, no need to test.
1285 	 */
1286 	if (!video->attached_count || video->child_count > 8)
1287 		return true;
1288 
1289 	for (i = 0; i < video->attached_count; i++) {
1290 		if ((video->attached_array[i].value.int_val & 0xfff) ==
1291 		    (device->device_id & 0xfff))
1292 			return true;
1293 	}
1294 
1295 	return false;
1296 }
1297 
1298 /*
1299  *  Arg:
1300  *	video	: video bus device
1301  *
1302  *  Return:
1303  *	< 0	: error
1304  *
1305  *  Call _DOD to enumerate all devices attached to display adapter
1306  *
1307  */
1308 
1309 static int acpi_video_device_enumerate(struct acpi_video_bus *video)
1310 {
1311 	int status;
1312 	int count;
1313 	int i;
1314 	struct acpi_video_enumerated_device *active_list;
1315 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
1316 	union acpi_object *dod = NULL;
1317 	union acpi_object *obj;
1318 
1319 	if (!video->cap._DOD)
1320 		return AE_NOT_EXIST;
1321 
1322 	status = acpi_evaluate_object(video->device->handle, "_DOD", NULL, &buffer);
1323 	if (!ACPI_SUCCESS(status)) {
1324 		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _DOD"));
1325 		return status;
1326 	}
1327 
1328 	dod = buffer.pointer;
1329 	if (!dod || (dod->type != ACPI_TYPE_PACKAGE)) {
1330 		ACPI_EXCEPTION((AE_INFO, status, "Invalid _DOD data"));
1331 		status = -EFAULT;
1332 		goto out;
1333 	}
1334 
1335 	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %d video heads in _DOD\n",
1336 			  dod->package.count));
1337 
1338 	active_list = kcalloc(1 + dod->package.count,
1339 			      sizeof(struct acpi_video_enumerated_device),
1340 			      GFP_KERNEL);
1341 	if (!active_list) {
1342 		status = -ENOMEM;
1343 		goto out;
1344 	}
1345 
1346 	count = 0;
1347 	for (i = 0; i < dod->package.count; i++) {
1348 		obj = &dod->package.elements[i];
1349 
1350 		if (obj->type != ACPI_TYPE_INTEGER) {
1351 			printk(KERN_ERR PREFIX
1352 				"Invalid _DOD data in element %d\n", i);
1353 			continue;
1354 		}
1355 
1356 		active_list[count].value.int_val = obj->integer.value;
1357 		active_list[count].bind_info = NULL;
1358 		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "dod element[%d] = %d\n", i,
1359 				  (int)obj->integer.value));
1360 		count++;
1361 	}
1362 
1363 	kfree(video->attached_array);
1364 
1365 	video->attached_array = active_list;
1366 	video->attached_count = count;
1367 
1368 out:
1369 	kfree(buffer.pointer);
1370 	return status;
1371 }
1372 
1373 static int
1374 acpi_video_get_next_level(struct acpi_video_device *device,
1375 			  u32 level_current, u32 event)
1376 {
1377 	int min, max, min_above, max_below, i, l, delta = 255;
1378 	max = max_below = 0;
1379 	min = min_above = 255;
1380 	/* Find closest level to level_current */
1381 	for (i = ACPI_VIDEO_FIRST_LEVEL; i < device->brightness->count; i++) {
1382 		l = device->brightness->levels[i];
1383 		if (abs(l - level_current) < abs(delta)) {
1384 			delta = l - level_current;
1385 			if (!delta)
1386 				break;
1387 		}
1388 	}
1389 	/* Ajust level_current to closest available level */
1390 	level_current += delta;
1391 	for (i = ACPI_VIDEO_FIRST_LEVEL; i < device->brightness->count; i++) {
1392 		l = device->brightness->levels[i];
1393 		if (l < min)
1394 			min = l;
1395 		if (l > max)
1396 			max = l;
1397 		if (l < min_above && l > level_current)
1398 			min_above = l;
1399 		if (l > max_below && l < level_current)
1400 			max_below = l;
1401 	}
1402 
1403 	switch (event) {
1404 	case ACPI_VIDEO_NOTIFY_CYCLE_BRIGHTNESS:
1405 		return (level_current < max) ? min_above : min;
1406 	case ACPI_VIDEO_NOTIFY_INC_BRIGHTNESS:
1407 		return (level_current < max) ? min_above : max;
1408 	case ACPI_VIDEO_NOTIFY_DEC_BRIGHTNESS:
1409 		return (level_current > min) ? max_below : min;
1410 	case ACPI_VIDEO_NOTIFY_ZERO_BRIGHTNESS:
1411 	case ACPI_VIDEO_NOTIFY_DISPLAY_OFF:
1412 		return 0;
1413 	default:
1414 		return level_current;
1415 	}
1416 }
1417 
1418 static void
1419 acpi_video_switch_brightness(struct work_struct *work)
1420 {
1421 	struct acpi_video_device *device = container_of(to_delayed_work(work),
1422 			     struct acpi_video_device, switch_brightness_work);
1423 	unsigned long long level_current, level_next;
1424 	int event = device->switch_brightness_event;
1425 	int result = -EINVAL;
1426 
1427 	/* no warning message if acpi_backlight=vendor or a quirk is used */
1428 	if (!device->backlight)
1429 		return;
1430 
1431 	if (!device->brightness)
1432 		goto out;
1433 
1434 	result = acpi_video_device_lcd_get_level_current(device,
1435 							 &level_current,
1436 							 false);
1437 	if (result)
1438 		goto out;
1439 
1440 	level_next = acpi_video_get_next_level(device, level_current, event);
1441 
1442 	result = acpi_video_device_lcd_set_level(device, level_next);
1443 
1444 	if (!result)
1445 		backlight_force_update(device->backlight,
1446 				       BACKLIGHT_UPDATE_HOTKEY);
1447 
1448 out:
1449 	if (result)
1450 		printk(KERN_ERR PREFIX "Failed to switch the brightness\n");
1451 }
1452 
1453 int acpi_video_get_edid(struct acpi_device *device, int type, int device_id,
1454 			void **edid)
1455 {
1456 	struct acpi_video_bus *video;
1457 	struct acpi_video_device *video_device;
1458 	union acpi_object *buffer = NULL;
1459 	acpi_status status;
1460 	int i, length;
1461 
1462 	if (!device || !acpi_driver_data(device))
1463 		return -EINVAL;
1464 
1465 	video = acpi_driver_data(device);
1466 
1467 	for (i = 0; i < video->attached_count; i++) {
1468 		video_device = video->attached_array[i].bind_info;
1469 		length = 256;
1470 
1471 		if (!video_device)
1472 			continue;
1473 
1474 		if (!video_device->cap._DDC)
1475 			continue;
1476 
1477 		if (type) {
1478 			switch (type) {
1479 			case ACPI_VIDEO_DISPLAY_CRT:
1480 				if (!video_device->flags.crt)
1481 					continue;
1482 				break;
1483 			case ACPI_VIDEO_DISPLAY_TV:
1484 				if (!video_device->flags.tvout)
1485 					continue;
1486 				break;
1487 			case ACPI_VIDEO_DISPLAY_DVI:
1488 				if (!video_device->flags.dvi)
1489 					continue;
1490 				break;
1491 			case ACPI_VIDEO_DISPLAY_LCD:
1492 				if (!video_device->flags.lcd)
1493 					continue;
1494 				break;
1495 			}
1496 		} else if (video_device->device_id != device_id) {
1497 			continue;
1498 		}
1499 
1500 		status = acpi_video_device_EDID(video_device, &buffer, length);
1501 
1502 		if (ACPI_FAILURE(status) || !buffer ||
1503 		    buffer->type != ACPI_TYPE_BUFFER) {
1504 			length = 128;
1505 			status = acpi_video_device_EDID(video_device, &buffer,
1506 							length);
1507 			if (ACPI_FAILURE(status) || !buffer ||
1508 			    buffer->type != ACPI_TYPE_BUFFER) {
1509 				continue;
1510 			}
1511 		}
1512 
1513 		*edid = buffer->buffer.pointer;
1514 		return length;
1515 	}
1516 
1517 	return -ENODEV;
1518 }
1519 EXPORT_SYMBOL(acpi_video_get_edid);
1520 
1521 static int
1522 acpi_video_bus_get_devices(struct acpi_video_bus *video,
1523 			   struct acpi_device *device)
1524 {
1525 	int status = 0;
1526 	struct acpi_device *dev;
1527 
1528 	/*
1529 	 * There are systems where video module known to work fine regardless
1530 	 * of broken _DOD and ignoring returned value here doesn't cause
1531 	 * any issues later.
1532 	 */
1533 	acpi_video_device_enumerate(video);
1534 
1535 	list_for_each_entry(dev, &device->children, node) {
1536 
1537 		status = acpi_video_bus_get_one_device(dev, video);
1538 		if (status) {
1539 			dev_err(&dev->dev, "Can't attach device\n");
1540 			break;
1541 		}
1542 		video->child_count++;
1543 	}
1544 	return status;
1545 }
1546 
1547 /* acpi_video interface */
1548 
1549 /*
1550  * Win8 requires setting bit2 of _DOS to let firmware know it shouldn't
1551  * preform any automatic brightness change on receiving a notification.
1552  */
1553 static int acpi_video_bus_start_devices(struct acpi_video_bus *video)
1554 {
1555 	return acpi_video_bus_DOS(video, 0,
1556 				  acpi_osi_is_win8() ? 1 : 0);
1557 }
1558 
1559 static int acpi_video_bus_stop_devices(struct acpi_video_bus *video)
1560 {
1561 	return acpi_video_bus_DOS(video, 0,
1562 				  acpi_osi_is_win8() ? 0 : 1);
1563 }
1564 
1565 static void acpi_video_bus_notify(struct acpi_device *device, u32 event)
1566 {
1567 	struct acpi_video_bus *video = acpi_driver_data(device);
1568 	struct input_dev *input;
1569 	int keycode = 0;
1570 
1571 	if (!video || !video->input)
1572 		return;
1573 
1574 	input = video->input;
1575 
1576 	switch (event) {
1577 	case ACPI_VIDEO_NOTIFY_SWITCH:	/* User requested a switch,
1578 					 * most likely via hotkey. */
1579 		keycode = KEY_SWITCHVIDEOMODE;
1580 		break;
1581 
1582 	case ACPI_VIDEO_NOTIFY_PROBE:	/* User plugged in or removed a video
1583 					 * connector. */
1584 		acpi_video_device_enumerate(video);
1585 		acpi_video_device_rebind(video);
1586 		keycode = KEY_SWITCHVIDEOMODE;
1587 		break;
1588 
1589 	case ACPI_VIDEO_NOTIFY_CYCLE:	/* Cycle Display output hotkey pressed. */
1590 		keycode = KEY_SWITCHVIDEOMODE;
1591 		break;
1592 	case ACPI_VIDEO_NOTIFY_NEXT_OUTPUT:	/* Next Display output hotkey pressed. */
1593 		keycode = KEY_VIDEO_NEXT;
1594 		break;
1595 	case ACPI_VIDEO_NOTIFY_PREV_OUTPUT:	/* previous Display output hotkey pressed. */
1596 		keycode = KEY_VIDEO_PREV;
1597 		break;
1598 
1599 	default:
1600 		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
1601 				  "Unsupported event [0x%x]\n", event));
1602 		break;
1603 	}
1604 
1605 	if (acpi_notifier_call_chain(device, event, 0))
1606 		/* Something vetoed the keypress. */
1607 		keycode = 0;
1608 
1609 	if (keycode && (report_key_events & REPORT_OUTPUT_KEY_EVENTS)) {
1610 		input_report_key(input, keycode, 1);
1611 		input_sync(input);
1612 		input_report_key(input, keycode, 0);
1613 		input_sync(input);
1614 	}
1615 
1616 	return;
1617 }
1618 
1619 static void brightness_switch_event(struct acpi_video_device *video_device,
1620 				    u32 event)
1621 {
1622 	if (!brightness_switch_enabled)
1623 		return;
1624 
1625 	video_device->switch_brightness_event = event;
1626 	schedule_delayed_work(&video_device->switch_brightness_work, HZ / 10);
1627 }
1628 
1629 static void acpi_video_device_notify(acpi_handle handle, u32 event, void *data)
1630 {
1631 	struct acpi_video_device *video_device = data;
1632 	struct acpi_device *device = NULL;
1633 	struct acpi_video_bus *bus;
1634 	struct input_dev *input;
1635 	int keycode = 0;
1636 
1637 	if (!video_device)
1638 		return;
1639 
1640 	device = video_device->dev;
1641 	bus = video_device->video;
1642 	input = bus->input;
1643 
1644 	if (hw_changes_brightness > 0) {
1645 		if (video_device->backlight)
1646 			backlight_force_update(video_device->backlight,
1647 					       BACKLIGHT_UPDATE_HOTKEY);
1648 		acpi_notifier_call_chain(device, event, 0);
1649 		return;
1650 	}
1651 
1652 	switch (event) {
1653 	case ACPI_VIDEO_NOTIFY_CYCLE_BRIGHTNESS:	/* Cycle brightness */
1654 		brightness_switch_event(video_device, event);
1655 		keycode = KEY_BRIGHTNESS_CYCLE;
1656 		break;
1657 	case ACPI_VIDEO_NOTIFY_INC_BRIGHTNESS:	/* Increase brightness */
1658 		brightness_switch_event(video_device, event);
1659 		keycode = KEY_BRIGHTNESSUP;
1660 		break;
1661 	case ACPI_VIDEO_NOTIFY_DEC_BRIGHTNESS:	/* Decrease brightness */
1662 		brightness_switch_event(video_device, event);
1663 		keycode = KEY_BRIGHTNESSDOWN;
1664 		break;
1665 	case ACPI_VIDEO_NOTIFY_ZERO_BRIGHTNESS:	/* zero brightness */
1666 		brightness_switch_event(video_device, event);
1667 		keycode = KEY_BRIGHTNESS_ZERO;
1668 		break;
1669 	case ACPI_VIDEO_NOTIFY_DISPLAY_OFF:	/* display device off */
1670 		brightness_switch_event(video_device, event);
1671 		keycode = KEY_DISPLAY_OFF;
1672 		break;
1673 	default:
1674 		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
1675 				  "Unsupported event [0x%x]\n", event));
1676 		break;
1677 	}
1678 
1679 	acpi_notifier_call_chain(device, event, 0);
1680 
1681 	if (keycode && (report_key_events & REPORT_BRIGHTNESS_KEY_EVENTS)) {
1682 		input_report_key(input, keycode, 1);
1683 		input_sync(input);
1684 		input_report_key(input, keycode, 0);
1685 		input_sync(input);
1686 	}
1687 
1688 	return;
1689 }
1690 
1691 static int acpi_video_resume(struct notifier_block *nb,
1692 				unsigned long val, void *ign)
1693 {
1694 	struct acpi_video_bus *video;
1695 	struct acpi_video_device *video_device;
1696 	int i;
1697 
1698 	switch (val) {
1699 	case PM_HIBERNATION_PREPARE:
1700 	case PM_SUSPEND_PREPARE:
1701 	case PM_RESTORE_PREPARE:
1702 		return NOTIFY_DONE;
1703 	}
1704 
1705 	video = container_of(nb, struct acpi_video_bus, pm_nb);
1706 
1707 	dev_info(&video->device->dev, "Restoring backlight state\n");
1708 
1709 	for (i = 0; i < video->attached_count; i++) {
1710 		video_device = video->attached_array[i].bind_info;
1711 		if (video_device && video_device->brightness)
1712 			acpi_video_device_lcd_set_level(video_device,
1713 					video_device->brightness->curr);
1714 	}
1715 
1716 	return NOTIFY_OK;
1717 }
1718 
1719 static acpi_status
1720 acpi_video_bus_match(acpi_handle handle, u32 level, void *context,
1721 			void **return_value)
1722 {
1723 	struct acpi_device *device = context;
1724 	struct acpi_device *sibling;
1725 	int result;
1726 
1727 	if (handle == device->handle)
1728 		return AE_CTRL_TERMINATE;
1729 
1730 	result = acpi_bus_get_device(handle, &sibling);
1731 	if (result)
1732 		return AE_OK;
1733 
1734 	if (!strcmp(acpi_device_name(sibling), ACPI_VIDEO_BUS_NAME))
1735 			return AE_ALREADY_EXISTS;
1736 
1737 	return AE_OK;
1738 }
1739 
1740 static void acpi_video_dev_register_backlight(struct acpi_video_device *device)
1741 {
1742 	struct backlight_properties props;
1743 	struct pci_dev *pdev;
1744 	acpi_handle acpi_parent;
1745 	struct device *parent = NULL;
1746 	int result;
1747 	static int count;
1748 	char *name;
1749 
1750 	result = acpi_video_init_brightness(device);
1751 	if (result)
1752 		return;
1753 
1754 	if (disable_backlight_sysfs_if > 0)
1755 		return;
1756 
1757 	name = kasprintf(GFP_KERNEL, "acpi_video%d", count);
1758 	if (!name)
1759 		return;
1760 	count++;
1761 
1762 	acpi_get_parent(device->dev->handle, &acpi_parent);
1763 
1764 	pdev = acpi_get_pci_dev(acpi_parent);
1765 	if (pdev) {
1766 		parent = &pdev->dev;
1767 		pci_dev_put(pdev);
1768 	}
1769 
1770 	memset(&props, 0, sizeof(struct backlight_properties));
1771 	props.type = BACKLIGHT_FIRMWARE;
1772 	props.max_brightness =
1773 		device->brightness->count - ACPI_VIDEO_FIRST_LEVEL - 1;
1774 	device->backlight = backlight_device_register(name,
1775 						      parent,
1776 						      device,
1777 						      &acpi_backlight_ops,
1778 						      &props);
1779 	kfree(name);
1780 	if (IS_ERR(device->backlight)) {
1781 		device->backlight = NULL;
1782 		return;
1783 	}
1784 
1785 	/*
1786 	 * Save current brightness level in case we have to restore it
1787 	 * before acpi_video_device_lcd_set_level() is called next time.
1788 	 */
1789 	device->backlight->props.brightness =
1790 			acpi_video_get_brightness(device->backlight);
1791 
1792 	device->cooling_dev = thermal_cooling_device_register("LCD",
1793 				device->dev, &video_cooling_ops);
1794 	if (IS_ERR(device->cooling_dev)) {
1795 		/*
1796 		 * Set cooling_dev to NULL so we don't crash trying to free it.
1797 		 * Also, why the hell we are returning early and not attempt to
1798 		 * register video output if cooling device registration failed?
1799 		 * -- dtor
1800 		 */
1801 		device->cooling_dev = NULL;
1802 		return;
1803 	}
1804 
1805 	dev_info(&device->dev->dev, "registered as cooling_device%d\n",
1806 		 device->cooling_dev->id);
1807 	result = sysfs_create_link(&device->dev->dev.kobj,
1808 			&device->cooling_dev->device.kobj,
1809 			"thermal_cooling");
1810 	if (result)
1811 		printk(KERN_ERR PREFIX "Create sysfs link\n");
1812 	result = sysfs_create_link(&device->cooling_dev->device.kobj,
1813 			&device->dev->dev.kobj, "device");
1814 	if (result)
1815 		printk(KERN_ERR PREFIX "Create sysfs link\n");
1816 }
1817 
1818 static void acpi_video_run_bcl_for_osi(struct acpi_video_bus *video)
1819 {
1820 	struct acpi_video_device *dev;
1821 	union acpi_object *levels;
1822 
1823 	mutex_lock(&video->device_list_lock);
1824 	list_for_each_entry(dev, &video->video_device_list, entry) {
1825 		if (!acpi_video_device_lcd_query_levels(dev->dev->handle, &levels))
1826 			kfree(levels);
1827 	}
1828 	mutex_unlock(&video->device_list_lock);
1829 }
1830 
1831 static bool acpi_video_should_register_backlight(struct acpi_video_device *dev)
1832 {
1833 	/*
1834 	 * Do not create backlight device for video output
1835 	 * device that is not in the enumerated list.
1836 	 */
1837 	if (!acpi_video_device_in_dod(dev)) {
1838 		dev_dbg(&dev->dev->dev, "not in _DOD list, ignore\n");
1839 		return false;
1840 	}
1841 
1842 	if (only_lcd)
1843 		return dev->flags.lcd;
1844 	return true;
1845 }
1846 
1847 static int acpi_video_bus_register_backlight(struct acpi_video_bus *video)
1848 {
1849 	struct acpi_video_device *dev;
1850 
1851 	if (video->backlight_registered)
1852 		return 0;
1853 
1854 	acpi_video_run_bcl_for_osi(video);
1855 
1856 	if (acpi_video_get_backlight_type() != acpi_backlight_video)
1857 		return 0;
1858 
1859 	mutex_lock(&video->device_list_lock);
1860 	list_for_each_entry(dev, &video->video_device_list, entry) {
1861 		if (acpi_video_should_register_backlight(dev))
1862 			acpi_video_dev_register_backlight(dev);
1863 	}
1864 	mutex_unlock(&video->device_list_lock);
1865 
1866 	video->backlight_registered = true;
1867 
1868 	video->pm_nb.notifier_call = acpi_video_resume;
1869 	video->pm_nb.priority = 0;
1870 	return register_pm_notifier(&video->pm_nb);
1871 }
1872 
1873 static void acpi_video_dev_unregister_backlight(struct acpi_video_device *device)
1874 {
1875 	if (device->backlight) {
1876 		backlight_device_unregister(device->backlight);
1877 		device->backlight = NULL;
1878 	}
1879 	if (device->brightness) {
1880 		kfree(device->brightness->levels);
1881 		kfree(device->brightness);
1882 		device->brightness = NULL;
1883 	}
1884 	if (device->cooling_dev) {
1885 		sysfs_remove_link(&device->dev->dev.kobj, "thermal_cooling");
1886 		sysfs_remove_link(&device->cooling_dev->device.kobj, "device");
1887 		thermal_cooling_device_unregister(device->cooling_dev);
1888 		device->cooling_dev = NULL;
1889 	}
1890 }
1891 
1892 static int acpi_video_bus_unregister_backlight(struct acpi_video_bus *video)
1893 {
1894 	struct acpi_video_device *dev;
1895 	int error;
1896 
1897 	if (!video->backlight_registered)
1898 		return 0;
1899 
1900 	error = unregister_pm_notifier(&video->pm_nb);
1901 
1902 	mutex_lock(&video->device_list_lock);
1903 	list_for_each_entry(dev, &video->video_device_list, entry)
1904 		acpi_video_dev_unregister_backlight(dev);
1905 	mutex_unlock(&video->device_list_lock);
1906 
1907 	video->backlight_registered = false;
1908 
1909 	return error;
1910 }
1911 
1912 static void acpi_video_dev_add_notify_handler(struct acpi_video_device *device)
1913 {
1914 	acpi_status status;
1915 	struct acpi_device *adev = device->dev;
1916 
1917 	status = acpi_install_notify_handler(adev->handle, ACPI_DEVICE_NOTIFY,
1918 					     acpi_video_device_notify, device);
1919 	if (ACPI_FAILURE(status))
1920 		dev_err(&adev->dev, "Error installing notify handler\n");
1921 	else
1922 		device->flags.notify = 1;
1923 }
1924 
1925 static int acpi_video_bus_add_notify_handler(struct acpi_video_bus *video)
1926 {
1927 	struct input_dev *input;
1928 	struct acpi_video_device *dev;
1929 	int error;
1930 
1931 	video->input = input = input_allocate_device();
1932 	if (!input) {
1933 		error = -ENOMEM;
1934 		goto out;
1935 	}
1936 
1937 	error = acpi_video_bus_start_devices(video);
1938 	if (error)
1939 		goto err_free_input;
1940 
1941 	snprintf(video->phys, sizeof(video->phys),
1942 			"%s/video/input0", acpi_device_hid(video->device));
1943 
1944 	input->name = acpi_device_name(video->device);
1945 	input->phys = video->phys;
1946 	input->id.bustype = BUS_HOST;
1947 	input->id.product = 0x06;
1948 	input->dev.parent = &video->device->dev;
1949 	input->evbit[0] = BIT(EV_KEY);
1950 	set_bit(KEY_SWITCHVIDEOMODE, input->keybit);
1951 	set_bit(KEY_VIDEO_NEXT, input->keybit);
1952 	set_bit(KEY_VIDEO_PREV, input->keybit);
1953 	set_bit(KEY_BRIGHTNESS_CYCLE, input->keybit);
1954 	set_bit(KEY_BRIGHTNESSUP, input->keybit);
1955 	set_bit(KEY_BRIGHTNESSDOWN, input->keybit);
1956 	set_bit(KEY_BRIGHTNESS_ZERO, input->keybit);
1957 	set_bit(KEY_DISPLAY_OFF, input->keybit);
1958 
1959 	error = input_register_device(input);
1960 	if (error)
1961 		goto err_stop_dev;
1962 
1963 	mutex_lock(&video->device_list_lock);
1964 	list_for_each_entry(dev, &video->video_device_list, entry)
1965 		acpi_video_dev_add_notify_handler(dev);
1966 	mutex_unlock(&video->device_list_lock);
1967 
1968 	return 0;
1969 
1970 err_stop_dev:
1971 	acpi_video_bus_stop_devices(video);
1972 err_free_input:
1973 	input_free_device(input);
1974 	video->input = NULL;
1975 out:
1976 	return error;
1977 }
1978 
1979 static void acpi_video_dev_remove_notify_handler(struct acpi_video_device *dev)
1980 {
1981 	if (dev->flags.notify) {
1982 		acpi_remove_notify_handler(dev->dev->handle, ACPI_DEVICE_NOTIFY,
1983 					   acpi_video_device_notify);
1984 		dev->flags.notify = 0;
1985 	}
1986 }
1987 
1988 static void acpi_video_bus_remove_notify_handler(struct acpi_video_bus *video)
1989 {
1990 	struct acpi_video_device *dev;
1991 
1992 	mutex_lock(&video->device_list_lock);
1993 	list_for_each_entry(dev, &video->video_device_list, entry)
1994 		acpi_video_dev_remove_notify_handler(dev);
1995 	mutex_unlock(&video->device_list_lock);
1996 
1997 	acpi_video_bus_stop_devices(video);
1998 	input_unregister_device(video->input);
1999 	video->input = NULL;
2000 }
2001 
2002 static int acpi_video_bus_put_devices(struct acpi_video_bus *video)
2003 {
2004 	struct acpi_video_device *dev, *next;
2005 
2006 	mutex_lock(&video->device_list_lock);
2007 	list_for_each_entry_safe(dev, next, &video->video_device_list, entry) {
2008 		list_del(&dev->entry);
2009 		kfree(dev);
2010 	}
2011 	mutex_unlock(&video->device_list_lock);
2012 
2013 	return 0;
2014 }
2015 
2016 static int instance;
2017 
2018 static int acpi_video_bus_add(struct acpi_device *device)
2019 {
2020 	struct acpi_video_bus *video;
2021 	int error;
2022 	acpi_status status;
2023 
2024 	status = acpi_walk_namespace(ACPI_TYPE_DEVICE,
2025 				device->parent->handle, 1,
2026 				acpi_video_bus_match, NULL,
2027 				device, NULL);
2028 	if (status == AE_ALREADY_EXISTS) {
2029 		printk(KERN_WARNING FW_BUG
2030 			"Duplicate ACPI video bus devices for the"
2031 			" same VGA controller, please try module "
2032 			"parameter \"video.allow_duplicates=1\""
2033 			"if the current driver doesn't work.\n");
2034 		if (!allow_duplicates)
2035 			return -ENODEV;
2036 	}
2037 
2038 	video = kzalloc(sizeof(struct acpi_video_bus), GFP_KERNEL);
2039 	if (!video)
2040 		return -ENOMEM;
2041 
2042 	/* a hack to fix the duplicate name "VID" problem on T61 */
2043 	if (!strcmp(device->pnp.bus_id, "VID")) {
2044 		if (instance)
2045 			device->pnp.bus_id[3] = '0' + instance;
2046 		instance++;
2047 	}
2048 	/* a hack to fix the duplicate name "VGA" problem on Pa 3553 */
2049 	if (!strcmp(device->pnp.bus_id, "VGA")) {
2050 		if (instance)
2051 			device->pnp.bus_id[3] = '0' + instance;
2052 		instance++;
2053 	}
2054 
2055 	video->device = device;
2056 	strcpy(acpi_device_name(device), ACPI_VIDEO_BUS_NAME);
2057 	strcpy(acpi_device_class(device), ACPI_VIDEO_CLASS);
2058 	device->driver_data = video;
2059 
2060 	acpi_video_bus_find_cap(video);
2061 	error = acpi_video_bus_check(video);
2062 	if (error)
2063 		goto err_free_video;
2064 
2065 	mutex_init(&video->device_list_lock);
2066 	INIT_LIST_HEAD(&video->video_device_list);
2067 
2068 	error = acpi_video_bus_get_devices(video, device);
2069 	if (error)
2070 		goto err_put_video;
2071 
2072 	printk(KERN_INFO PREFIX "%s [%s] (multi-head: %s  rom: %s  post: %s)\n",
2073 	       ACPI_VIDEO_DEVICE_NAME, acpi_device_bid(device),
2074 	       video->flags.multihead ? "yes" : "no",
2075 	       video->flags.rom ? "yes" : "no",
2076 	       video->flags.post ? "yes" : "no");
2077 	mutex_lock(&video_list_lock);
2078 	list_add_tail(&video->entry, &video_bus_head);
2079 	mutex_unlock(&video_list_lock);
2080 
2081 	acpi_video_bus_register_backlight(video);
2082 	acpi_video_bus_add_notify_handler(video);
2083 
2084 	return 0;
2085 
2086 err_put_video:
2087 	acpi_video_bus_put_devices(video);
2088 	kfree(video->attached_array);
2089 err_free_video:
2090 	kfree(video);
2091 	device->driver_data = NULL;
2092 
2093 	return error;
2094 }
2095 
2096 static int acpi_video_bus_remove(struct acpi_device *device)
2097 {
2098 	struct acpi_video_bus *video = NULL;
2099 
2100 
2101 	if (!device || !acpi_driver_data(device))
2102 		return -EINVAL;
2103 
2104 	video = acpi_driver_data(device);
2105 
2106 	acpi_video_bus_remove_notify_handler(video);
2107 	acpi_video_bus_unregister_backlight(video);
2108 	acpi_video_bus_put_devices(video);
2109 
2110 	mutex_lock(&video_list_lock);
2111 	list_del(&video->entry);
2112 	mutex_unlock(&video_list_lock);
2113 
2114 	kfree(video->attached_array);
2115 	kfree(video);
2116 
2117 	return 0;
2118 }
2119 
2120 static int __init is_i740(struct pci_dev *dev)
2121 {
2122 	if (dev->device == 0x00D1)
2123 		return 1;
2124 	if (dev->device == 0x7000)
2125 		return 1;
2126 	return 0;
2127 }
2128 
2129 static int __init intel_opregion_present(void)
2130 {
2131 	int opregion = 0;
2132 	struct pci_dev *dev = NULL;
2133 	u32 address;
2134 
2135 	for_each_pci_dev(dev) {
2136 		if ((dev->class >> 8) != PCI_CLASS_DISPLAY_VGA)
2137 			continue;
2138 		if (dev->vendor != PCI_VENDOR_ID_INTEL)
2139 			continue;
2140 		/* We don't want to poke around undefined i740 registers */
2141 		if (is_i740(dev))
2142 			continue;
2143 		pci_read_config_dword(dev, 0xfc, &address);
2144 		if (!address)
2145 			continue;
2146 		opregion = 1;
2147 	}
2148 	return opregion;
2149 }
2150 
2151 /* Check if the chassis-type indicates there is no builtin LCD panel */
2152 static bool dmi_is_desktop(void)
2153 {
2154 	const char *chassis_type;
2155 	unsigned long type;
2156 
2157 	chassis_type = dmi_get_system_info(DMI_CHASSIS_TYPE);
2158 	if (!chassis_type)
2159 		return false;
2160 
2161 	if (kstrtoul(chassis_type, 10, &type) != 0)
2162 		return false;
2163 
2164 	switch (type) {
2165 	case 0x03: /* Desktop */
2166 	case 0x04: /* Low Profile Desktop */
2167 	case 0x05: /* Pizza Box */
2168 	case 0x06: /* Mini Tower */
2169 	case 0x07: /* Tower */
2170 	case 0x10: /* Lunch Box */
2171 	case 0x11: /* Main Server Chassis */
2172 		return true;
2173 	}
2174 
2175 	return false;
2176 }
2177 
2178 int acpi_video_register(void)
2179 {
2180 	int ret = 0;
2181 
2182 	mutex_lock(&register_count_mutex);
2183 	if (register_count) {
2184 		/*
2185 		 * if the function of acpi_video_register is already called,
2186 		 * don't register the acpi_vide_bus again and return no error.
2187 		 */
2188 		goto leave;
2189 	}
2190 
2191 	/*
2192 	 * We're seeing a lot of bogus backlight interfaces on newer machines
2193 	 * without a LCD such as desktops, servers and HDMI sticks. Checking
2194 	 * the lcd flag fixes this, so enable this on any machines which are
2195 	 * win8 ready (where we also prefer the native backlight driver, so
2196 	 * normally the acpi_video code should not register there anyways).
2197 	 */
2198 	if (only_lcd == -1) {
2199 		if (dmi_is_desktop() && acpi_osi_is_win8())
2200 			only_lcd = true;
2201 		else
2202 			only_lcd = false;
2203 	}
2204 
2205 	dmi_check_system(video_dmi_table);
2206 
2207 	ret = acpi_bus_register_driver(&acpi_video_bus);
2208 	if (ret)
2209 		goto leave;
2210 
2211 	/*
2212 	 * When the acpi_video_bus is loaded successfully, increase
2213 	 * the counter reference.
2214 	 */
2215 	register_count = 1;
2216 
2217 leave:
2218 	mutex_unlock(&register_count_mutex);
2219 	return ret;
2220 }
2221 EXPORT_SYMBOL(acpi_video_register);
2222 
2223 void acpi_video_unregister(void)
2224 {
2225 	mutex_lock(&register_count_mutex);
2226 	if (register_count) {
2227 		acpi_bus_unregister_driver(&acpi_video_bus);
2228 		register_count = 0;
2229 	}
2230 	mutex_unlock(&register_count_mutex);
2231 }
2232 EXPORT_SYMBOL(acpi_video_unregister);
2233 
2234 void acpi_video_unregister_backlight(void)
2235 {
2236 	struct acpi_video_bus *video;
2237 
2238 	mutex_lock(&register_count_mutex);
2239 	if (register_count) {
2240 		mutex_lock(&video_list_lock);
2241 		list_for_each_entry(video, &video_bus_head, entry)
2242 			acpi_video_bus_unregister_backlight(video);
2243 		mutex_unlock(&video_list_lock);
2244 	}
2245 	mutex_unlock(&register_count_mutex);
2246 }
2247 
2248 bool acpi_video_handles_brightness_key_presses(void)
2249 {
2250 	bool have_video_busses;
2251 
2252 	mutex_lock(&video_list_lock);
2253 	have_video_busses = !list_empty(&video_bus_head);
2254 	mutex_unlock(&video_list_lock);
2255 
2256 	return have_video_busses &&
2257 	       (report_key_events & REPORT_BRIGHTNESS_KEY_EVENTS);
2258 }
2259 EXPORT_SYMBOL(acpi_video_handles_brightness_key_presses);
2260 
2261 /*
2262  * This is kind of nasty. Hardware using Intel chipsets may require
2263  * the video opregion code to be run first in order to initialise
2264  * state before any ACPI video calls are made. To handle this we defer
2265  * registration of the video class until the opregion code has run.
2266  */
2267 
2268 static int __init acpi_video_init(void)
2269 {
2270 	/*
2271 	 * Let the module load even if ACPI is disabled (e.g. due to
2272 	 * a broken BIOS) so that i915.ko can still be loaded on such
2273 	 * old systems without an AcpiOpRegion.
2274 	 *
2275 	 * acpi_video_register() will report -ENODEV later as well due
2276 	 * to acpi_disabled when i915.ko tries to register itself afterwards.
2277 	 */
2278 	if (acpi_disabled)
2279 		return 0;
2280 
2281 	if (intel_opregion_present())
2282 		return 0;
2283 
2284 	return acpi_video_register();
2285 }
2286 
2287 static void __exit acpi_video_exit(void)
2288 {
2289 	acpi_video_detect_exit();
2290 	acpi_video_unregister();
2291 
2292 	return;
2293 }
2294 
2295 module_init(acpi_video_init);
2296 module_exit(acpi_video_exit);
2297