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 void acpi_video_unregister_backlight(void); 39 40 static bool backlight_notifier_registered; 41 static struct notifier_block backlight_nb; 42 static struct work_struct backlight_notify_work; 43 44 static enum acpi_backlight_type acpi_backlight_cmdline = acpi_backlight_undef; 45 static enum acpi_backlight_type acpi_backlight_dmi = acpi_backlight_undef; 46 47 static void acpi_video_parse_cmdline(void) 48 { 49 if (!strcmp("vendor", acpi_video_backlight_string)) 50 acpi_backlight_cmdline = acpi_backlight_vendor; 51 if (!strcmp("video", acpi_video_backlight_string)) 52 acpi_backlight_cmdline = acpi_backlight_video; 53 if (!strcmp("native", acpi_video_backlight_string)) 54 acpi_backlight_cmdline = acpi_backlight_native; 55 if (!strcmp("none", acpi_video_backlight_string)) 56 acpi_backlight_cmdline = acpi_backlight_none; 57 } 58 59 static acpi_status 60 find_video(acpi_handle handle, u32 lvl, void *context, void **rv) 61 { 62 struct acpi_device *acpi_dev = acpi_fetch_acpi_dev(handle); 63 long *cap = context; 64 struct pci_dev *dev; 65 66 static const struct acpi_device_id video_ids[] = { 67 {ACPI_VIDEO_HID, 0}, 68 {"", 0}, 69 }; 70 71 if (acpi_dev && !acpi_match_device_ids(acpi_dev, video_ids)) { 72 dev = acpi_get_pci_dev(handle); 73 if (!dev) 74 return AE_OK; 75 pci_dev_put(dev); 76 *cap |= acpi_is_video_device(handle); 77 } 78 return AE_OK; 79 } 80 81 /* Force to use vendor driver when the ACPI device is known to be 82 * buggy */ 83 static int video_detect_force_vendor(const struct dmi_system_id *d) 84 { 85 acpi_backlight_dmi = acpi_backlight_vendor; 86 return 0; 87 } 88 89 static int video_detect_force_video(const struct dmi_system_id *d) 90 { 91 acpi_backlight_dmi = acpi_backlight_video; 92 return 0; 93 } 94 95 static int video_detect_force_native(const struct dmi_system_id *d) 96 { 97 acpi_backlight_dmi = acpi_backlight_native; 98 return 0; 99 } 100 101 static int video_detect_force_none(const struct dmi_system_id *d) 102 { 103 acpi_backlight_dmi = acpi_backlight_none; 104 return 0; 105 } 106 107 static const struct dmi_system_id video_detect_dmi_table[] = { 108 /* On Samsung X360, the BIOS will set a flag (VDRV) if generic 109 * ACPI backlight device is used. This flag will definitively break 110 * the backlight interface (even the vendor interface) until next 111 * reboot. It's why we should prevent video.ko from being used here 112 * and we can't rely on a later call to acpi_video_unregister(). 113 */ 114 { 115 .callback = video_detect_force_vendor, 116 /* X360 */ 117 .matches = { 118 DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."), 119 DMI_MATCH(DMI_PRODUCT_NAME, "X360"), 120 DMI_MATCH(DMI_BOARD_NAME, "X360"), 121 }, 122 }, 123 { 124 .callback = video_detect_force_vendor, 125 /* Asus UL30VT */ 126 .matches = { 127 DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK Computer Inc."), 128 DMI_MATCH(DMI_PRODUCT_NAME, "UL30VT"), 129 }, 130 }, 131 { 132 .callback = video_detect_force_vendor, 133 /* Asus UL30A */ 134 .matches = { 135 DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK Computer Inc."), 136 DMI_MATCH(DMI_PRODUCT_NAME, "UL30A"), 137 }, 138 }, 139 { 140 .callback = video_detect_force_vendor, 141 /* GIGABYTE GB-BXBT-2807 */ 142 .matches = { 143 DMI_MATCH(DMI_SYS_VENDOR, "GIGABYTE"), 144 DMI_MATCH(DMI_PRODUCT_NAME, "GB-BXBT-2807"), 145 }, 146 }, 147 { 148 .callback = video_detect_force_vendor, 149 /* Sony VPCEH3U1E */ 150 .matches = { 151 DMI_MATCH(DMI_SYS_VENDOR, "Sony Corporation"), 152 DMI_MATCH(DMI_PRODUCT_NAME, "VPCEH3U1E"), 153 }, 154 }, 155 { 156 .callback = video_detect_force_vendor, 157 /* Xiaomi Mi Pad 2 */ 158 .matches = { 159 DMI_MATCH(DMI_SYS_VENDOR, "Xiaomi Inc"), 160 DMI_MATCH(DMI_PRODUCT_NAME, "Mipad2"), 161 }, 162 }, 163 164 /* 165 * These models have a working acpi_video backlight control, and using 166 * native backlight causes a regression where backlight does not work 167 * when userspace is not handling brightness key events. Disable 168 * native_backlight on these to fix this: 169 * https://bugzilla.kernel.org/show_bug.cgi?id=81691 170 */ 171 { 172 .callback = video_detect_force_video, 173 /* ThinkPad T420 */ 174 .matches = { 175 DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"), 176 DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad T420"), 177 }, 178 }, 179 { 180 .callback = video_detect_force_video, 181 /* ThinkPad T520 */ 182 .matches = { 183 DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"), 184 DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad T520"), 185 }, 186 }, 187 { 188 .callback = video_detect_force_video, 189 /* ThinkPad X201s */ 190 .matches = { 191 DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"), 192 DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad X201s"), 193 }, 194 }, 195 { 196 .callback = video_detect_force_video, 197 /* ThinkPad X201T */ 198 .matches = { 199 DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"), 200 DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad X201T"), 201 }, 202 }, 203 204 /* The native backlight controls do not work on some older machines */ 205 { 206 /* https://bugs.freedesktop.org/show_bug.cgi?id=81515 */ 207 .callback = video_detect_force_video, 208 /* HP ENVY 15 Notebook */ 209 .matches = { 210 DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"), 211 DMI_MATCH(DMI_PRODUCT_NAME, "HP ENVY 15 Notebook PC"), 212 }, 213 }, 214 { 215 .callback = video_detect_force_video, 216 /* SAMSUNG 870Z5E/880Z5E/680Z5E */ 217 .matches = { 218 DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."), 219 DMI_MATCH(DMI_PRODUCT_NAME, "870Z5E/880Z5E/680Z5E"), 220 }, 221 }, 222 { 223 .callback = video_detect_force_video, 224 /* SAMSUNG 370R4E/370R4V/370R5E/3570RE/370R5V */ 225 .matches = { 226 DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."), 227 DMI_MATCH(DMI_PRODUCT_NAME, 228 "370R4E/370R4V/370R5E/3570RE/370R5V"), 229 }, 230 }, 231 { 232 /* https://bugzilla.redhat.com/show_bug.cgi?id=1186097 */ 233 .callback = video_detect_force_video, 234 /* SAMSUNG 3570R/370R/470R/450R/510R/4450RV */ 235 .matches = { 236 DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."), 237 DMI_MATCH(DMI_PRODUCT_NAME, 238 "3570R/370R/470R/450R/510R/4450RV"), 239 }, 240 }, 241 { 242 /* https://bugzilla.redhat.com/show_bug.cgi?id=1557060 */ 243 .callback = video_detect_force_video, 244 /* SAMSUNG 670Z5E */ 245 .matches = { 246 DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."), 247 DMI_MATCH(DMI_PRODUCT_NAME, "670Z5E"), 248 }, 249 }, 250 { 251 /* https://bugzilla.redhat.com/show_bug.cgi?id=1094948 */ 252 .callback = video_detect_force_video, 253 /* SAMSUNG 730U3E/740U3E */ 254 .matches = { 255 DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."), 256 DMI_MATCH(DMI_PRODUCT_NAME, "730U3E/740U3E"), 257 }, 258 }, 259 { 260 /* https://bugs.freedesktop.org/show_bug.cgi?id=87286 */ 261 .callback = video_detect_force_video, 262 /* SAMSUNG 900X3C/900X3D/900X3E/900X4C/900X4D */ 263 .matches = { 264 DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."), 265 DMI_MATCH(DMI_PRODUCT_NAME, 266 "900X3C/900X3D/900X3E/900X4C/900X4D"), 267 }, 268 }, 269 { 270 /* https://bugzilla.redhat.com/show_bug.cgi?id=1272633 */ 271 .callback = video_detect_force_video, 272 /* Dell XPS14 L421X */ 273 .matches = { 274 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."), 275 DMI_MATCH(DMI_PRODUCT_NAME, "XPS L421X"), 276 }, 277 }, 278 { 279 /* https://bugzilla.redhat.com/show_bug.cgi?id=1163574 */ 280 .callback = video_detect_force_video, 281 /* Dell XPS15 L521X */ 282 .matches = { 283 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."), 284 DMI_MATCH(DMI_PRODUCT_NAME, "XPS L521X"), 285 }, 286 }, 287 { 288 /* https://bugzilla.kernel.org/show_bug.cgi?id=108971 */ 289 .callback = video_detect_force_video, 290 /* SAMSUNG 530U4E/540U4E */ 291 .matches = { 292 DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."), 293 DMI_MATCH(DMI_PRODUCT_NAME, "530U4E/540U4E"), 294 }, 295 }, 296 /* https://bugs.launchpad.net/bugs/1894667 */ 297 { 298 .callback = video_detect_force_video, 299 /* HP 635 Notebook */ 300 .matches = { 301 DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"), 302 DMI_MATCH(DMI_PRODUCT_NAME, "HP 635 Notebook PC"), 303 }, 304 }, 305 306 /* Non win8 machines which need native backlight nevertheless */ 307 { 308 /* https://bugzilla.redhat.com/show_bug.cgi?id=1201530 */ 309 .callback = video_detect_force_native, 310 /* Lenovo Ideapad S405 */ 311 .matches = { 312 DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"), 313 DMI_MATCH(DMI_BOARD_NAME, "Lenovo IdeaPad S405"), 314 }, 315 }, 316 { 317 /* https://bugzilla.redhat.com/show_bug.cgi?id=1187004 */ 318 .callback = video_detect_force_native, 319 /* Lenovo Ideapad Z570 */ 320 .matches = { 321 DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"), 322 DMI_MATCH(DMI_PRODUCT_NAME, "102434U"), 323 }, 324 }, 325 { 326 .callback = video_detect_force_native, 327 /* Lenovo E41-25 */ 328 .matches = { 329 DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"), 330 DMI_MATCH(DMI_PRODUCT_NAME, "81FS"), 331 }, 332 }, 333 { 334 .callback = video_detect_force_native, 335 /* Lenovo E41-45 */ 336 .matches = { 337 DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"), 338 DMI_MATCH(DMI_PRODUCT_NAME, "82BK"), 339 }, 340 }, 341 { 342 /* https://bugzilla.redhat.com/show_bug.cgi?id=1217249 */ 343 .callback = video_detect_force_native, 344 /* Apple MacBook Pro 12,1 */ 345 .matches = { 346 DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."), 347 DMI_MATCH(DMI_PRODUCT_NAME, "MacBookPro12,1"), 348 }, 349 }, 350 { 351 .callback = video_detect_force_native, 352 /* Dell Inspiron N4010 */ 353 .matches = { 354 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."), 355 DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron N4010"), 356 }, 357 }, 358 { 359 .callback = video_detect_force_native, 360 /* Dell Vostro V131 */ 361 .matches = { 362 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."), 363 DMI_MATCH(DMI_PRODUCT_NAME, "Vostro V131"), 364 }, 365 }, 366 { 367 /* https://bugzilla.redhat.com/show_bug.cgi?id=1123661 */ 368 .callback = video_detect_force_native, 369 /* Dell XPS 17 L702X */ 370 .matches = { 371 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."), 372 DMI_MATCH(DMI_PRODUCT_NAME, "Dell System XPS L702X"), 373 }, 374 }, 375 { 376 .callback = video_detect_force_native, 377 /* Dell Precision 7510 */ 378 .matches = { 379 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."), 380 DMI_MATCH(DMI_PRODUCT_NAME, "Precision 7510"), 381 }, 382 }, 383 { 384 .callback = video_detect_force_native, 385 /* Acer Aspire 5738z */ 386 .matches = { 387 DMI_MATCH(DMI_SYS_VENDOR, "Acer"), 388 DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5738"), 389 DMI_MATCH(DMI_BOARD_NAME, "JV50"), 390 }, 391 }, 392 { 393 /* https://bugzilla.kernel.org/show_bug.cgi?id=207835 */ 394 .callback = video_detect_force_native, 395 /* Acer TravelMate 5735Z */ 396 .matches = { 397 DMI_MATCH(DMI_SYS_VENDOR, "Acer"), 398 DMI_MATCH(DMI_PRODUCT_NAME, "TravelMate 5735Z"), 399 DMI_MATCH(DMI_BOARD_NAME, "BA51_MV"), 400 }, 401 }, 402 { 403 .callback = video_detect_force_native, 404 /* ASUSTeK COMPUTER INC. GA401 */ 405 .matches = { 406 DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."), 407 DMI_MATCH(DMI_PRODUCT_NAME, "GA401"), 408 }, 409 }, 410 { 411 .callback = video_detect_force_native, 412 /* ASUSTeK COMPUTER INC. GA502 */ 413 .matches = { 414 DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."), 415 DMI_MATCH(DMI_PRODUCT_NAME, "GA502"), 416 }, 417 }, 418 { 419 .callback = video_detect_force_native, 420 /* ASUSTeK COMPUTER INC. GA503 */ 421 .matches = { 422 DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."), 423 DMI_MATCH(DMI_PRODUCT_NAME, "GA503"), 424 }, 425 }, 426 /* 427 * Clevo NL5xRU and NL5xNU/TUXEDO Aura 15 Gen1 and Gen2 have both a 428 * working native and video interface. However the default detection 429 * mechanism first registers the video interface before unregistering 430 * it again and switching to the native interface during boot. This 431 * results in a dangling SBIOS request for backlight change for some 432 * reason, causing the backlight to switch to ~2% once per boot on the 433 * first power cord connect or disconnect event. Setting the native 434 * interface explicitly circumvents this buggy behaviour, by avoiding 435 * the unregistering process. 436 */ 437 { 438 .callback = video_detect_force_native, 439 .ident = "Clevo NL5xRU", 440 .matches = { 441 DMI_MATCH(DMI_BOARD_NAME, "NL5xRU"), 442 }, 443 }, 444 { 445 .callback = video_detect_force_native, 446 .ident = "Clevo NL5xRU", 447 .matches = { 448 DMI_MATCH(DMI_SYS_VENDOR, "TUXEDO"), 449 DMI_MATCH(DMI_BOARD_NAME, "AURA1501"), 450 }, 451 }, 452 { 453 .callback = video_detect_force_native, 454 .ident = "Clevo NL5xRU", 455 .matches = { 456 DMI_MATCH(DMI_SYS_VENDOR, "TUXEDO"), 457 DMI_MATCH(DMI_BOARD_NAME, "EDUBOOK1502"), 458 }, 459 }, 460 { 461 .callback = video_detect_force_native, 462 .ident = "Clevo NL5xNU", 463 .matches = { 464 DMI_MATCH(DMI_BOARD_NAME, "NL5xNU"), 465 }, 466 }, 467 /* 468 * The TongFang PF5PU1G, PF4NU1F, PF5NU1G, and PF5LUXG/TUXEDO BA15 Gen10, 469 * Pulse 14/15 Gen1, and Pulse 15 Gen2 have the same problem as the Clevo 470 * NL5xRU and NL5xNU/TUXEDO Aura 15 Gen1 and Gen2. See the description 471 * above. 472 */ 473 { 474 .callback = video_detect_force_native, 475 .ident = "TongFang PF5PU1G", 476 .matches = { 477 DMI_MATCH(DMI_BOARD_NAME, "PF5PU1G"), 478 }, 479 }, 480 { 481 .callback = video_detect_force_native, 482 .ident = "TongFang PF4NU1F", 483 .matches = { 484 DMI_MATCH(DMI_BOARD_NAME, "PF4NU1F"), 485 }, 486 }, 487 { 488 .callback = video_detect_force_native, 489 .ident = "TongFang PF4NU1F", 490 .matches = { 491 DMI_MATCH(DMI_SYS_VENDOR, "TUXEDO"), 492 DMI_MATCH(DMI_BOARD_NAME, "PULSE1401"), 493 }, 494 }, 495 { 496 .callback = video_detect_force_native, 497 .ident = "TongFang PF5NU1G", 498 .matches = { 499 DMI_MATCH(DMI_BOARD_NAME, "PF5NU1G"), 500 }, 501 }, 502 { 503 .callback = video_detect_force_native, 504 .ident = "TongFang PF5NU1G", 505 .matches = { 506 DMI_MATCH(DMI_SYS_VENDOR, "TUXEDO"), 507 DMI_MATCH(DMI_BOARD_NAME, "PULSE1501"), 508 }, 509 }, 510 { 511 .callback = video_detect_force_native, 512 .ident = "TongFang PF5LUXG", 513 .matches = { 514 DMI_MATCH(DMI_BOARD_NAME, "PF5LUXG"), 515 }, 516 }, 517 /* 518 * Desktops which falsely report a backlight and which our heuristics 519 * for this do not catch. 520 */ 521 { 522 .callback = video_detect_force_none, 523 /* Dell OptiPlex 9020M */ 524 .matches = { 525 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."), 526 DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 9020M"), 527 }, 528 }, 529 { 530 .callback = video_detect_force_none, 531 /* MSI MS-7721 */ 532 .matches = { 533 DMI_MATCH(DMI_SYS_VENDOR, "MSI"), 534 DMI_MATCH(DMI_PRODUCT_NAME, "MS-7721"), 535 }, 536 }, 537 { }, 538 }; 539 540 /* This uses a workqueue to avoid various locking ordering issues */ 541 static void acpi_video_backlight_notify_work(struct work_struct *work) 542 { 543 if (acpi_video_get_backlight_type() != acpi_backlight_video) 544 acpi_video_unregister_backlight(); 545 } 546 547 static int acpi_video_backlight_notify(struct notifier_block *nb, 548 unsigned long val, void *bd) 549 { 550 struct backlight_device *backlight = bd; 551 552 /* A raw bl registering may change video -> native */ 553 if (backlight->props.type == BACKLIGHT_RAW && 554 val == BACKLIGHT_REGISTERED) 555 schedule_work(&backlight_notify_work); 556 557 return NOTIFY_OK; 558 } 559 560 /* 561 * Determine which type of backlight interface to use on this system, 562 * First check cmdline, then dmi quirks, then do autodetect. 563 * 564 * The autodetect order is: 565 * 1) Is the acpi-video backlight interface supported -> 566 * no, use a vendor interface 567 * 2) Is this a win8 "ready" BIOS and do we have a native interface -> 568 * yes, use a native interface 569 * 3) Else use the acpi-video interface 570 * 571 * Arguably the native on win8 check should be done first, but that would 572 * be a behavior change, which may causes issues. 573 */ 574 enum acpi_backlight_type acpi_video_get_backlight_type(void) 575 { 576 static DEFINE_MUTEX(init_mutex); 577 static bool init_done; 578 static long video_caps; 579 580 /* Parse cmdline, dmi and acpi only once */ 581 mutex_lock(&init_mutex); 582 if (!init_done) { 583 acpi_video_parse_cmdline(); 584 dmi_check_system(video_detect_dmi_table); 585 acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT, 586 ACPI_UINT32_MAX, find_video, NULL, 587 &video_caps, NULL); 588 INIT_WORK(&backlight_notify_work, 589 acpi_video_backlight_notify_work); 590 backlight_nb.notifier_call = acpi_video_backlight_notify; 591 backlight_nb.priority = 0; 592 if (backlight_register_notifier(&backlight_nb) == 0) 593 backlight_notifier_registered = true; 594 init_done = true; 595 } 596 mutex_unlock(&init_mutex); 597 598 if (acpi_backlight_cmdline != acpi_backlight_undef) 599 return acpi_backlight_cmdline; 600 601 if (acpi_backlight_dmi != acpi_backlight_undef) 602 return acpi_backlight_dmi; 603 604 if (!(video_caps & ACPI_VIDEO_BACKLIGHT)) 605 return acpi_backlight_vendor; 606 607 if (acpi_osi_is_win8() && backlight_device_get_by_type(BACKLIGHT_RAW)) 608 return acpi_backlight_native; 609 610 return acpi_backlight_video; 611 } 612 EXPORT_SYMBOL(acpi_video_get_backlight_type); 613 614 /* 615 * Set the preferred backlight interface type based on DMI info. 616 * This function allows DMI blacklists to be implemented by external 617 * platform drivers instead of putting a big blacklist in video_detect.c 618 */ 619 void acpi_video_set_dmi_backlight_type(enum acpi_backlight_type type) 620 { 621 acpi_backlight_dmi = type; 622 /* Remove acpi-video backlight interface if it is no longer desired */ 623 if (acpi_video_get_backlight_type() != acpi_backlight_video) 624 acpi_video_unregister_backlight(); 625 } 626 EXPORT_SYMBOL(acpi_video_set_dmi_backlight_type); 627 628 void __exit acpi_video_detect_exit(void) 629 { 630 if (backlight_notifier_registered) 631 backlight_unregister_notifier(&backlight_nb); 632 } 633