drivers/acpi/video_detect.c

   1 /*
   2  *  Copyright (C) 2015       Red Hat Inc.
   3  *                           Hans de Goede <hdegoede@redhat.com>
   4  *  Copyright (C) 2008       SuSE Linux Products GmbH
   5  *                           Thomas Renninger <trenn@suse.de>
   6  *
   7  *  May be copied or modified under the terms of the GNU General Public License
   8  *
   9  * video_detect.c:
  10  * After PCI devices are glued with ACPI devices
  11  * acpi_get_pci_dev() can be called to identify ACPI graphics
  12  * devices for which a real graphics card is plugged in
  13  *
  14  * Depending on whether ACPI graphics extensions (cmp. ACPI spec Appendix B)
  15  * are available, video.ko should be used to handle the device.
  16  *
  17  * Otherwise vendor specific drivers like thinkpad_acpi, asus-laptop,
  18  * sony_acpi,... can take care about backlight brightness.
  19  *
  20  * Backlight drivers can use acpi_video_get_backlight_type() to determine
  21  * which driver should handle the backlight.
  22  *
  23  * If CONFIG_ACPI_VIDEO is neither set as "compiled in" (y) nor as a module (m)
  24  * this file will not be compiled and acpi_video_get_backlight_type() will
  25  * always return acpi_backlight_vendor.
  26  */
  27
  28 #include <linux/export.h>
  29 #include <linux/acpi.h>
  30 #include <linux/backlight.h>
  31 #include <linux/dmi.h>
  32 #include <linux/module.h>
  33 #include <linux/pci.h>
  34 #include <linux/types.h>
  35 #include <linux/workqueue.h>
  36 #include <acpi/video.h>
  37
  38 ACPI_MODULE_NAME("video");
  39 #define _COMPONENT              ACPI_VIDEO_COMPONENT
  40
  41 void acpi_video_unregister_backlight(void);
  42
  43 static bool backlight_notifier_registered;
  44 static struct notifier_block backlight_nb;
  45 static struct work_struct backlight_notify_work;
  46
  47 static enum acpi_backlight_type acpi_backlight_cmdline = acpi_backlight_undef;
  48 static enum acpi_backlight_type acpi_backlight_dmi = acpi_backlight_undef;
  49
  50 static void acpi_video_parse_cmdline(void)
  51 {
  52         if (!strcmp("vendor", acpi_video_backlight_string))
  53                 acpi_backlight_cmdline = acpi_backlight_vendor;
  54         if (!strcmp("video", acpi_video_backlight_string))
  55                 acpi_backlight_cmdline = acpi_backlight_video;
  56         if (!strcmp("native", acpi_video_backlight_string))
  57                 acpi_backlight_cmdline = acpi_backlight_native;
  58         if (!strcmp("none", acpi_video_backlight_string))
  59                 acpi_backlight_cmdline = acpi_backlight_none;
  60 }
  61
  62 static acpi_status
  63 find_video(acpi_handle handle, u32 lvl, void *context, void **rv)
  64 {
  65         long *cap = context;
  66         struct pci_dev *dev;
  67         struct acpi_device *acpi_dev;
  68
  69         static const struct acpi_device_id video_ids[] = {
  70                 {ACPI_VIDEO_HID, 0},
  71                 {"", 0},
  72         };
  73         if (acpi_bus_get_device(handle, &acpi_dev))
  74                 return AE_OK;
  75
  76         if (!acpi_match_device_ids(acpi_dev, video_ids)) {
  77                 dev = acpi_get_pci_dev(handle);
  78                 if (!dev)
  79                         return AE_OK;
  80                 pci_dev_put(dev);
  81                 *cap |= acpi_is_video_device(handle);
  82         }
  83         return AE_OK;
  84 }
  85
  86 /* Force to use vendor driver when the ACPI device is known to be
  87  * buggy */
  88 static int video_detect_force_vendor(const struct dmi_system_id *d)
  89 {
  90         acpi_backlight_dmi = acpi_backlight_vendor;
  91         return 0;
  92 }
  93
  94 static int video_detect_force_video(const struct dmi_system_id *d)
  95 {
  96         acpi_backlight_dmi = acpi_backlight_video;
  97         return 0;
  98 }
  99
 100 static int video_detect_force_native(const struct dmi_system_id *d)
 101 {
 102         acpi_backlight_dmi = acpi_backlight_native;
 103         return 0;
 104 }
 105
 106 static const struct dmi_system_id video_detect_dmi_table[] = {
 107         /* On Samsung X360, the BIOS will set a flag (VDRV) if generic
 108          * ACPI backlight device is used. This flag will definitively break
 109          * the backlight interface (even the vendor interface) untill next
 110          * reboot. It's why we should prevent video.ko from being used here
 111          * and we can't rely on a later call to acpi_video_unregister().
 112          */
 113         {
 114          .callback = video_detect_force_vendor,
 115          .ident = "X360",
 116          .matches = {
 117                 DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."),
 118                 DMI_MATCH(DMI_PRODUCT_NAME, "X360"),
 119                 DMI_MATCH(DMI_BOARD_NAME, "X360"),
 120                 },
 121         },
 122         {
 123         .callback = video_detect_force_vendor,
 124         .ident = "Asus UL30VT",
 125         .matches = {
 126                 DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK Computer Inc."),
 127                 DMI_MATCH(DMI_PRODUCT_NAME, "UL30VT"),
 128                 },
 129         },
 130         {
 131         .callback = video_detect_force_vendor,
 132         .ident = "Asus UL30A",
 133         .matches = {
 134                 DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK Computer Inc."),
 135                 DMI_MATCH(DMI_PRODUCT_NAME, "UL30A"),
 136                 },
 137         },
 138         /*
 139          * Clevo NL5xRU and NL5xNU/TUXEDO Aura 15 Gen1 and Gen2 have both a
 140          * working native and video interface. However the default detection
 141          * mechanism first registers the video interface before unregistering
 142          * it again and switching to the native interface during boot. This
 143          * results in a dangling SBIOS request for backlight change for some
 144          * reason, causing the backlight to switch to ~2% once per boot on the
 145          * first power cord connect or disconnect event. Setting the native
 146          * interface explicitly circumvents this buggy behaviour, by avoiding
 147          * the unregistering process.
 148          */
 149         {
 150         .callback = video_detect_force_native,
 151         .ident = "Clevo NL5xRU",
 152         .matches = {
 153                 DMI_MATCH(DMI_BOARD_NAME, "NL5xRU"),
 154                 },
 155         },
 156         {
 157         .callback = video_detect_force_native,
 158         .ident = "Clevo NL5xRU",
 159         .matches = {
 160                 DMI_MATCH(DMI_SYS_VENDOR, "TUXEDO"),
 161                 DMI_MATCH(DMI_BOARD_NAME, "AURA1501"),
 162                 },
 163         },
 164         {
 165         .callback = video_detect_force_native,
 166         .ident = "Clevo NL5xRU",
 167         .matches = {
 168                 DMI_MATCH(DMI_SYS_VENDOR, "TUXEDO"),
 169                 DMI_MATCH(DMI_BOARD_NAME, "EDUBOOK1502"),
 170                 },
 171         },
 172         {
 173         .callback = video_detect_force_native,
 174         .ident = "Clevo NL5xNU",
 175         .matches = {
 176                 DMI_MATCH(DMI_BOARD_NAME, "NL5xNU"),
 177                 },
 178         },
 179         /*
 180          * The TongFang PF5PU1G, PF4NU1F, PF5NU1G, and PF5LUXG/TUXEDO BA15 Gen10,
 181          * Pulse 14/15 Gen1, and Pulse 15 Gen2 have the same problem as the Clevo
 182          * NL5xRU and NL5xNU/TUXEDO Aura 15 Gen1 and Gen2. See the description
 183          * above.
 184          */
 185         {
 186         .callback = video_detect_force_native,
 187         .ident = "TongFang PF5PU1G",
 188         .matches = {
 189                 DMI_MATCH(DMI_BOARD_NAME, "PF5PU1G"),
 190                 },
 191         },
 192         {
 193         .callback = video_detect_force_native,
 194         .ident = "TongFang PF4NU1F",
 195         .matches = {
 196                 DMI_MATCH(DMI_BOARD_NAME, "PF4NU1F"),
 197                 },
 198         },
 199         {
 200         .callback = video_detect_force_native,
 201         .ident = "TongFang PF4NU1F",
 202         .matches = {
 203                 DMI_MATCH(DMI_SYS_VENDOR, "TUXEDO"),
 204                 DMI_MATCH(DMI_BOARD_NAME, "PULSE1401"),
 205                 },
 206         },
 207         {
 208         .callback = video_detect_force_native,
 209         .ident = "TongFang PF5NU1G",
 210         .matches = {
 211                 DMI_MATCH(DMI_BOARD_NAME, "PF5NU1G"),
 212                 },
 213         },
 214         {
 215         .callback = video_detect_force_native,
 216         .ident = "TongFang PF5NU1G",
 217         .matches = {
 218                 DMI_MATCH(DMI_SYS_VENDOR, "TUXEDO"),
 219                 DMI_MATCH(DMI_BOARD_NAME, "PULSE1501"),
 220                 },
 221         },
 222         {
 223         .callback = video_detect_force_native,
 224         .ident = "TongFang PF5LUXG",
 225         .matches = {
 226                 DMI_MATCH(DMI_BOARD_NAME, "PF5LUXG"),
 227                 },
 228         },
 229         /*
 230          * More Tongfang devices with the same issue as the Clevo NL5xRU and
 231          * NL5xNU/TUXEDO Aura 15 Gen1 and Gen2. See the description above.
 232          */
 233         {
 234         .callback = video_detect_force_native,
 235         .ident = "TongFang GKxNRxx",
 236         .matches = {
 237                 DMI_MATCH(DMI_BOARD_NAME, "GKxNRxx"),
 238                 },
 239         },
 240         {
 241         .callback = video_detect_force_native,
 242         .ident = "TongFang GKxNRxx",
 243         .matches = {
 244                 DMI_MATCH(DMI_SYS_VENDOR, "TUXEDO"),
 245                 DMI_MATCH(DMI_BOARD_NAME, "POLARIS1501A1650TI"),
 246                 },
 247         },
 248         {
 249         .callback = video_detect_force_native,
 250         .ident = "TongFang GKxNRxx",
 251         .matches = {
 252                 DMI_MATCH(DMI_SYS_VENDOR, "TUXEDO"),
 253                 DMI_MATCH(DMI_BOARD_NAME, "POLARIS1501A2060"),
 254                 },
 255         },
 256         {
 257         .callback = video_detect_force_native,
 258         .ident = "TongFang GKxNRxx",
 259         .matches = {
 260                 DMI_MATCH(DMI_SYS_VENDOR, "TUXEDO"),
 261                 DMI_MATCH(DMI_BOARD_NAME, "POLARIS1701A1650TI"),
 262                 },
 263         },
 264         {
 265         .callback = video_detect_force_native,
 266         .ident = "TongFang GKxNRxx",
 267         .matches = {
 268                 DMI_MATCH(DMI_SYS_VENDOR, "TUXEDO"),
 269                 DMI_MATCH(DMI_BOARD_NAME, "POLARIS1701A2060"),
 270                 },
 271         },
 272         {
 273         .callback = video_detect_force_native,
 274         .ident = "TongFang GMxNGxx",
 275         .matches = {
 276                 DMI_MATCH(DMI_BOARD_NAME, "GMxNGxx"),
 277                 },
 278         },
 279         {
 280         .callback = video_detect_force_native,
 281         .ident = "TongFang GMxZGxx",
 282         .matches = {
 283                 DMI_MATCH(DMI_BOARD_NAME, "GMxZGxx"),
 284                 },
 285         },
 286         {
 287         .callback = video_detect_force_native,
 288         .ident = "TongFang GMxRGxx",
 289         .matches = {
 290                 DMI_MATCH(DMI_BOARD_NAME, "GMxRGxx"),
 291                 },
 292         },
 293         /*
 294          * These models have a working acpi_video backlight control, and using
 295          * native backlight causes a regression where backlight does not work
 296          * when userspace is not handling brightness key events. Disable
 297          * native_backlight on these to fix this:
 298          * https://bugzilla.kernel.org/show_bug.cgi?id=81691
 299          */
 300         {
 301          .callback = video_detect_force_video,
 302          .ident = "ThinkPad T420",
 303          .matches = {
 304                 DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
 305                 DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad T420"),
 306                 },
 307         },
 308         {
 309          .callback = video_detect_force_video,
 310          .ident = "ThinkPad T520",
 311          .matches = {
 312                 DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
 313                 DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad T520"),
 314                 },
 315         },
 316         {
 317          .callback = video_detect_force_video,
 318          .ident = "ThinkPad X201s",
 319          .matches = {
 320                 DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
 321                 DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad X201s"),
 322                 },
 323         },
 324         {
 325          .callback = video_detect_force_video,
 326          .ident = "ThinkPad X201T",
 327          .matches = {
 328                 DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
 329                 DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad X201T"),
 330                 },
 331         },
 332
 333         /* The native backlight controls do not work on some older machines */
 334         {
 335          /* https://bugs.freedesktop.org/show_bug.cgi?id=81515 */
 336          .callback = video_detect_force_video,
 337          .ident = "HP ENVY 15 Notebook",
 338          .matches = {
 339                 DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
 340                 DMI_MATCH(DMI_PRODUCT_NAME, "HP ENVY 15 Notebook PC"),
 341                 },
 342         },
 343         {
 344          .callback = video_detect_force_video,
 345          .ident = "SAMSUNG 870Z5E/880Z5E/680Z5E",
 346          .matches = {
 347                 DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."),
 348                 DMI_MATCH(DMI_PRODUCT_NAME, "870Z5E/880Z5E/680Z5E"),
 349                 },
 350         },
 351         {
 352          .callback = video_detect_force_video,
 353          .ident = "SAMSUNG 370R4E/370R4V/370R5E/3570RE/370R5V",
 354          .matches = {
 355                 DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."),
 356                 DMI_MATCH(DMI_PRODUCT_NAME,
 357                           "370R4E/370R4V/370R5E/3570RE/370R5V"),
 358                 },
 359         },
 360         {
 361          /* https://bugzilla.redhat.com/show_bug.cgi?id=1186097 */
 362          .callback = video_detect_force_video,
 363          .ident = "SAMSUNG 3570R/370R/470R/450R/510R/4450RV",
 364          .matches = {
 365                 DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."),
 366                 DMI_MATCH(DMI_PRODUCT_NAME,
 367                           "3570R/370R/470R/450R/510R/4450RV"),
 368                 },
 369         },
 370         {
 371          /* https://bugzilla.redhat.com/show_bug.cgi?id=1557060 */
 372          .callback = video_detect_force_video,
 373          .ident = "SAMSUNG 670Z5E",
 374          .matches = {
 375                 DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."),
 376                 DMI_MATCH(DMI_PRODUCT_NAME, "670Z5E"),
 377                 },
 378         },
 379         {
 380          /* https://bugzilla.redhat.com/show_bug.cgi?id=1094948 */
 381          .callback = video_detect_force_video,
 382          .ident = "SAMSUNG 730U3E/740U3E",
 383          .matches = {
 384                 DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."),
 385                 DMI_MATCH(DMI_PRODUCT_NAME, "730U3E/740U3E"),
 386                 },
 387         },
 388         {
 389          /* https://bugs.freedesktop.org/show_bug.cgi?id=87286 */
 390          .callback = video_detect_force_video,
 391          .ident = "SAMSUNG 900X3C/900X3D/900X3E/900X4C/900X4D",
 392          .matches = {
 393                 DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."),
 394                 DMI_MATCH(DMI_PRODUCT_NAME,
 395                           "900X3C/900X3D/900X3E/900X4C/900X4D"),
 396                 },
 397         },
 398         {
 399          /* https://bugzilla.redhat.com/show_bug.cgi?id=1272633 */
 400          .callback = video_detect_force_video,
 401          .ident = "Dell XPS14 L421X",
 402          .matches = {
 403                 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 404                 DMI_MATCH(DMI_PRODUCT_NAME, "XPS L421X"),
 405                 },
 406         },
 407         {
 408          /* https://bugzilla.redhat.com/show_bug.cgi?id=1163574 */
 409          .callback = video_detect_force_video,
 410          .ident = "Dell XPS15 L521X",
 411          .matches = {
 412                 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 413                 DMI_MATCH(DMI_PRODUCT_NAME, "XPS L521X"),
 414                 },
 415         },
 416         {
 417          /* https://bugzilla.kernel.org/show_bug.cgi?id=108971 */
 418          .callback = video_detect_force_video,
 419          .ident = "SAMSUNG 530U4E/540U4E",
 420          .matches = {
 421                 DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."),
 422                 DMI_MATCH(DMI_PRODUCT_NAME, "530U4E/540U4E"),
 423                 },
 424         },
 425         /* https://bugs.launchpad.net/bugs/1894667 */
 426         {
 427          .callback = video_detect_force_video,
 428          .ident = "HP 635 Notebook",
 429          .matches = {
 430                 DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
 431                 DMI_MATCH(DMI_PRODUCT_NAME, "HP 635 Notebook PC"),
 432                 },
 433         },
 434
 435         /* Non win8 machines which need native backlight nevertheless */
 436         {
 437          /* https://bugzilla.redhat.com/show_bug.cgi?id=1201530 */
 438          .callback = video_detect_force_native,
 439          .ident = "Lenovo Ideapad S405",
 440          .matches = {
 441                 DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
 442                 DMI_MATCH(DMI_BOARD_NAME, "Lenovo IdeaPad S405"),
 443                 },
 444         },
 445         {
 446          /* https://bugzilla.redhat.com/show_bug.cgi?id=1187004 */
 447          .callback = video_detect_force_native,
 448          .ident = "Lenovo Ideapad Z570",
 449          .matches = {
 450                 DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
 451                 DMI_MATCH(DMI_PRODUCT_NAME, "102434U"),
 452                 },
 453         },
 454         {
 455          /* https://bugzilla.redhat.com/show_bug.cgi?id=1217249 */
 456          .callback = video_detect_force_native,
 457          .ident = "Apple MacBook Pro 12,1",
 458          .matches = {
 459                 DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
 460                 DMI_MATCH(DMI_PRODUCT_NAME, "MacBookPro12,1"),
 461                 },
 462         },
 463         {
 464          .callback = video_detect_force_native,
 465          .ident = "Dell Vostro V131",
 466          .matches = {
 467                 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 468                 DMI_MATCH(DMI_PRODUCT_NAME, "Vostro V131"),
 469                 },
 470         },
 471         {
 472          /* https://bugzilla.redhat.com/show_bug.cgi?id=1123661 */
 473          .callback = video_detect_force_native,
 474          .ident = "Dell XPS 17 L702X",
 475          .matches = {
 476                 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 477                 DMI_MATCH(DMI_PRODUCT_NAME, "Dell System XPS L702X"),
 478                 },
 479         },
 480         { },
 481 };
 482
 483 /* This uses a workqueue to avoid various locking ordering issues */
 484 static void acpi_video_backlight_notify_work(struct work_struct *work)
 485 {
 486         if (acpi_video_get_backlight_type() != acpi_backlight_video)
 487                 acpi_video_unregister_backlight();
 488 }
 489
 490 static int acpi_video_backlight_notify(struct notifier_block *nb,
 491                                        unsigned long val, void *bd)
 492 {
 493         struct backlight_device *backlight = bd;
 494
 495         /* A raw bl registering may change video -> native */
 496         if (backlight->props.type == BACKLIGHT_RAW &&
 497             val == BACKLIGHT_REGISTERED)
 498                 schedule_work(&backlight_notify_work);
 499
 500         return NOTIFY_OK;
 501 }
 502
 503 /*
 504  * Determine which type of backlight interface to use on this system,
 505  * First check cmdline, then dmi quirks, then do autodetect.
 506  *
 507  * The autodetect order is:
 508  * 1) Is the acpi-video backlight interface supported ->
 509  *  no, use a vendor interface
 510  * 2) Is this a win8 "ready" BIOS and do we have a native interface ->
 511  *  yes, use a native interface
 512  * 3) Else use the acpi-video interface
 513  *
 514  * Arguably the native on win8 check should be done first, but that would
 515  * be a behavior change, which may causes issues.
 516  */
 517 enum acpi_backlight_type acpi_video_get_backlight_type(void)
 518 {
 519         static DEFINE_MUTEX(init_mutex);
 520         static bool init_done;
 521         static long video_caps;
 522
 523         /* Parse cmdline, dmi and acpi only once */
 524         mutex_lock(&init_mutex);
 525         if (!init_done) {
 526                 acpi_video_parse_cmdline();
 527                 dmi_check_system(video_detect_dmi_table);
 528                 acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
 529                                     ACPI_UINT32_MAX, find_video, NULL,
 530                                     &video_caps, NULL);
 531                 INIT_WORK(&backlight_notify_work,
 532                           acpi_video_backlight_notify_work);
 533                 backlight_nb.notifier_call = acpi_video_backlight_notify;
 534                 backlight_nb.priority = 0;
 535                 if (backlight_register_notifier(&backlight_nb) == 0)
 536                         backlight_notifier_registered = true;
 537                 init_done = true;
 538         }
 539         mutex_unlock(&init_mutex);
 540
 541         if (acpi_backlight_cmdline != acpi_backlight_undef)
 542                 return acpi_backlight_cmdline;
 543
 544         if (acpi_backlight_dmi != acpi_backlight_undef)
 545                 return acpi_backlight_dmi;
 546
 547         if (!(video_caps & ACPI_VIDEO_BACKLIGHT))
 548                 return acpi_backlight_vendor;
 549
 550         if (acpi_osi_is_win8() && backlight_device_get_by_type(BACKLIGHT_RAW))
 551                 return acpi_backlight_native;
 552
 553         return acpi_backlight_video;
 554 }
 555 EXPORT_SYMBOL(acpi_video_get_backlight_type);
 556
 557 /*
 558  * Set the preferred backlight interface type based on DMI info.
 559  * This function allows DMI blacklists to be implemented by external
 560  * platform drivers instead of putting a big blacklist in video_detect.c
 561  */
 562 void acpi_video_set_dmi_backlight_type(enum acpi_backlight_type type)
 563 {
 564         acpi_backlight_dmi = type;
 565         /* Remove acpi-video backlight interface if it is no longer desired */
 566         if (acpi_video_get_backlight_type() != acpi_backlight_video)
 567                 acpi_video_unregister_backlight();
 568 }
 569 EXPORT_SYMBOL(acpi_video_set_dmi_backlight_type);
 570
 571 void __exit acpi_video_detect_exit(void)
 572 {
 573         if (backlight_notifier_registered)
 574                 backlight_unregister_notifier(&backlight_nb);
 575 }