drivers/acpi/video_detect.c - LeafOS-Devices/android_kernel_realme_mt6785 - Gitiles

 /*
  *  Copyright (C) 2015       Red Hat Inc.
  *                           Hans de Goede <hdegoede@redhat.com>
  *  Copyright (C) 2008       SuSE Linux Products GmbH
  *                           Thomas Renninger <trenn@suse.de>
  *
  *  May be copied or modified under the terms of the GNU General Public License
  *
  * video_detect.c:
  * After PCI devices are glued with ACPI devices
  * acpi_get_pci_dev() can be called to identify ACPI graphics
  * devices for which a real graphics card is plugged in
  *
  * Depending on whether ACPI graphics extensions (cmp. ACPI spec Appendix B)
  * are available, video.ko should be used to handle the device.
  *
  * Otherwise vendor specific drivers like thinkpad_acpi, asus-laptop,
  * sony_acpi,... can take care about backlight brightness.
  *
  * Backlight drivers can use acpi_video_get_backlight_type() to determine
  * which driver should handle the backlight.
  *
  * If CONFIG_ACPI_VIDEO is neither set as "compiled in" (y) nor as a module (m)
  * this file will not be compiled and acpi_video_get_backlight_type() will
  * always return acpi_backlight_vendor.
  */

 #include <linux/export.h>
 #include <linux/acpi.h>
 #include <linux/backlight.h>
 #include <linux/dmi.h>
 #include <linux/module.h>
 #include <linux/pci.h>
 #include <linux/types.h>
 #include <linux/workqueue.h>
 #include <acpi/video.h>

 ACPI_MODULE_NAME("video");
 #define _COMPONENT		ACPI_VIDEO_COMPONENT

 void acpi_video_unregister_backlight(void);

 static bool backlight_notifier_registered;
 static struct notifier_block backlight_nb;
 static struct work_struct backlight_notify_work;

 static enum acpi_backlight_type acpi_backlight_cmdline = acpi_backlight_undef;
 static enum acpi_backlight_type acpi_backlight_dmi = acpi_backlight_undef;

 static void acpi_video_parse_cmdline(void)
 {
 	if (!strcmp("vendor", acpi_video_backlight_string))
 		acpi_backlight_cmdline = acpi_backlight_vendor;
 	if (!strcmp("video", acpi_video_backlight_string))
 		acpi_backlight_cmdline = acpi_backlight_video;
 	if (!strcmp("native", acpi_video_backlight_string))
 		acpi_backlight_cmdline = acpi_backlight_native;
 	if (!strcmp("none", acpi_video_backlight_string))
 		acpi_backlight_cmdline = acpi_backlight_none;
 }

 static acpi_status
 find_video(acpi_handle handle, u32 lvl, void *context, void **rv)
 {
 	long *cap = context;
 	struct pci_dev *dev;
 	struct acpi_device *acpi_dev;

 	static const struct acpi_device_id video_ids[] = {
 		{ACPI_VIDEO_HID, 0},
 		{"", 0},
 	};
 	if (acpi_bus_get_device(handle, &acpi_dev))
 		return AE_OK;

 	if (!acpi_match_device_ids(acpi_dev, video_ids)) {
 		dev = acpi_get_pci_dev(handle);
 		if (!dev)
 			return AE_OK;
 		pci_dev_put(dev);
 		*cap |= acpi_is_video_device(handle);
 	}
 	return AE_OK;
 }

 /* Force to use vendor driver when the ACPI device is known to be
  * buggy */
 static int video_detect_force_vendor(const struct dmi_system_id *d)
 {
 	acpi_backlight_dmi = acpi_backlight_vendor;
 	return 0;
 }

 static int video_detect_force_video(const struct dmi_system_id *d)
 {
 	acpi_backlight_dmi = acpi_backlight_video;
 	return 0;
 }

 static int video_detect_force_native(const struct dmi_system_id *d)
 {
 	acpi_backlight_dmi = acpi_backlight_native;
 	return 0;
 }

 static int video_detect_force_none(const struct dmi_system_id *d)
 {
 	acpi_backlight_dmi = acpi_backlight_none;
 	return 0;
 }

 static const struct dmi_system_id video_detect_dmi_table[] = {
 	/* On Samsung X360, the BIOS will set a flag (VDRV) if generic
 	 * ACPI backlight device is used. This flag will definitively break
 	 * the backlight interface (even the vendor interface) untill next
 	 * reboot. It's why we should prevent video.ko from being used here
 	 * and we can't rely on a later call to acpi_video_unregister().
 	 */
 	{
 	 .callback = video_detect_force_vendor,
 	 .ident = "X360",
 	 .matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."),
 		DMI_MATCH(DMI_PRODUCT_NAME, "X360"),
 		DMI_MATCH(DMI_BOARD_NAME, "X360"),
 		},
 	},
 	{
 	.callback = video_detect_force_vendor,
 	.ident = "Asus UL30VT",
 	.matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK Computer Inc."),
 		DMI_MATCH(DMI_PRODUCT_NAME, "UL30VT"),
 		},
 	},
 	{
 	.callback = video_detect_force_vendor,
 	.ident = "Asus UL30A",
 	.matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK Computer Inc."),
 		DMI_MATCH(DMI_PRODUCT_NAME, "UL30A"),
 		},
 	},

 	/*
 	 * These models have a working acpi_video backlight control, and using
 	 * native backlight causes a regression where backlight does not work
 	 * when userspace is not handling brightness key events. Disable
 	 * native_backlight on these to fix this:
 	 * https://bugzilla.kernel.org/show_bug.cgi?id=81691
 	 */
 	{
 	 .callback = video_detect_force_video,
 	 .ident = "ThinkPad T420",
 	 .matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
 		DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad T420"),
 		},
 	},
 	{
 	 .callback = video_detect_force_video,
 	 .ident = "ThinkPad T520",
 	 .matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
 		DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad T520"),
 		},
 	},
 	{
 	 .callback = video_detect_force_video,
 	 .ident = "ThinkPad X201s",
 	 .matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
 		DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad X201s"),
 		},
 	},
         {
          .callback = video_detect_force_video,
          .ident = "ThinkPad X201T",
          .matches = {
                 DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
                 DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad X201T"),
                 },
         },

 	/* The native backlight controls do not work on some older machines */
 	{
 	 /* https://bugs.freedesktop.org/show_bug.cgi?id=81515 */
 	 .callback = video_detect_force_video,
 	 .ident = "HP ENVY 15 Notebook",
 	 .matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
 		DMI_MATCH(DMI_PRODUCT_NAME, "HP ENVY 15 Notebook PC"),
 		},
 	},
 	{
 	 .callback = video_detect_force_video,
 	 .ident = "SAMSUNG 870Z5E/880Z5E/680Z5E",
 	 .matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."),
 		DMI_MATCH(DMI_PRODUCT_NAME, "870Z5E/880Z5E/680Z5E"),
 		},
 	},
 	{
 	 .callback = video_detect_force_video,
 	 .ident = "SAMSUNG 370R4E/370R4V/370R5E/3570RE/370R5V",
 	 .matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."),
 		DMI_MATCH(DMI_PRODUCT_NAME,
 			  "370R4E/370R4V/370R5E/3570RE/370R5V"),
 		},
 	},
 	{
 	 /* https://bugzilla.redhat.com/show_bug.cgi?id=1186097 */
 	 .callback = video_detect_force_video,
 	 .ident = "SAMSUNG 3570R/370R/470R/450R/510R/4450RV",
 	 .matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."),
 		DMI_MATCH(DMI_PRODUCT_NAME,
 			  "3570R/370R/470R/450R/510R/4450RV"),
 		},
 	},
 	{
 	 /* https://bugzilla.redhat.com/show_bug.cgi?id=1557060 */
 	 .callback = video_detect_force_video,
 	 .ident = "SAMSUNG 670Z5E",
 	 .matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."),
 		DMI_MATCH(DMI_PRODUCT_NAME, "670Z5E"),
 		},
 	},
 	{
 	 /* https://bugzilla.redhat.com/show_bug.cgi?id=1094948 */
 	 .callback = video_detect_force_video,
 	 .ident = "SAMSUNG 730U3E/740U3E",
 	 .matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."),
 		DMI_MATCH(DMI_PRODUCT_NAME, "730U3E/740U3E"),
 		},
 	},
 	{
 	 /* https://bugs.freedesktop.org/show_bug.cgi?id=87286 */
 	 .callback = video_detect_force_video,
 	 .ident = "SAMSUNG 900X3C/900X3D/900X3E/900X4C/900X4D",
 	 .matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."),
 		DMI_MATCH(DMI_PRODUCT_NAME,
 			  "900X3C/900X3D/900X3E/900X4C/900X4D"),
 		},
 	},
 	{
 	 /* https://bugzilla.redhat.com/show_bug.cgi?id=1272633 */
 	 .callback = video_detect_force_video,
 	 .ident = "Dell XPS14 L421X",
 	 .matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 		DMI_MATCH(DMI_PRODUCT_NAME, "XPS L421X"),
 		},
 	},
 	{
 	 /* https://bugzilla.redhat.com/show_bug.cgi?id=1163574 */
 	 .callback = video_detect_force_video,
 	 .ident = "Dell XPS15 L521X",
 	 .matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 		DMI_MATCH(DMI_PRODUCT_NAME, "XPS L521X"),
 		},
 	},
 	{
 	 /* https://bugzilla.kernel.org/show_bug.cgi?id=108971 */
 	 .callback = video_detect_force_video,
 	 .ident = "SAMSUNG 530U4E/540U4E",
 	 .matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."),
 		DMI_MATCH(DMI_PRODUCT_NAME, "530U4E/540U4E"),
 		},
 	},
 	/* https://bugs.launchpad.net/bugs/1894667 */
 	{
 	 .callback = video_detect_force_video,
 	 .ident = "HP 635 Notebook",
 	 .matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
 		DMI_MATCH(DMI_PRODUCT_NAME, "HP 635 Notebook PC"),
 		},
 	},

 	/* Non win8 machines which need native backlight nevertheless */
 	{
 	 /* https://bugzilla.redhat.com/show_bug.cgi?id=1201530 */
 	 .callback = video_detect_force_native,
 	 .ident = "Lenovo Ideapad S405",
 	 .matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
 		DMI_MATCH(DMI_BOARD_NAME, "Lenovo IdeaPad S405"),
 		},
 	},
 	{
 	 /* https://bugzilla.redhat.com/show_bug.cgi?id=1187004 */
 	 .callback = video_detect_force_native,
 	 .ident = "Lenovo Ideapad Z570",
 	 .matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
 		DMI_MATCH(DMI_PRODUCT_VERSION, "Ideapad Z570"),
 		},
 	},
 	{
 	 /* https://bugzilla.redhat.com/show_bug.cgi?id=1217249 */
 	 .callback = video_detect_force_native,
 	 .ident = "Apple MacBook Pro 12,1",
 	 .matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
 		DMI_MATCH(DMI_PRODUCT_NAME, "MacBookPro12,1"),
 		},
 	},
 	{
 	 .callback = video_detect_force_native,
 	 .ident = "Dell Vostro V131",
 	 .matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 		DMI_MATCH(DMI_PRODUCT_NAME, "Vostro V131"),
 		},
 	},
 	{
 	 /* https://bugzilla.redhat.com/show_bug.cgi?id=1123661 */
 	 .callback = video_detect_force_native,
 	 .ident = "Dell XPS 17 L702X",
 	 .matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 		DMI_MATCH(DMI_PRODUCT_NAME, "Dell System XPS L702X"),
 		},
 	},
 	{
 	 .callback = video_detect_force_native,
 	 .ident = "Dell Precision 7510",
 	 .matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 		DMI_MATCH(DMI_PRODUCT_NAME, "Precision 7510"),
 		},
 	},
 	{
 	 .callback = video_detect_force_native,
 	 .ident = "Acer Aspire 5738z",
 	 .matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
 		DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5738"),
 		DMI_MATCH(DMI_BOARD_NAME, "JV50"),
 		},
 	},
 	{
 	 /* https://bugzilla.kernel.org/show_bug.cgi?id=207835 */
 	 .callback = video_detect_force_native,
 	 .ident = "Acer TravelMate 5735Z",
 	 .matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
 		DMI_MATCH(DMI_PRODUCT_NAME, "TravelMate 5735Z"),
 		DMI_MATCH(DMI_BOARD_NAME, "BA51_MV"),
 		},
 	},
 	/*
 	 * Clevo NL5xRU and NL5xNU/TUXEDO Aura 15 Gen1 and Gen2 have both a
 	 * working native and video interface. However the default detection
 	 * mechanism first registers the video interface before unregistering
 	 * it again and switching to the native interface during boot. This
 	 * results in a dangling SBIOS request for backlight change for some
 	 * reason, causing the backlight to switch to ~2% once per boot on the
 	 * first power cord connect or disconnect event. Setting the native
 	 * interface explicitly circumvents this buggy behaviour, by avoiding
 	 * the unregistering process.
 	 */
 	{
 	.callback = video_detect_force_native,
 	.ident = "Clevo NL5xRU",
 	.matches = {
 		DMI_MATCH(DMI_BOARD_NAME, "NL5xRU"),
 		},
 	},
 	{
 	.callback = video_detect_force_native,
 	.ident = "Clevo NL5xRU",
 	.matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "TUXEDO"),
 		DMI_MATCH(DMI_BOARD_NAME, "AURA1501"),
 		},
 	},
 	{
 	.callback = video_detect_force_native,
 	.ident = "Clevo NL5xRU",
 	.matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "TUXEDO"),
 		DMI_MATCH(DMI_BOARD_NAME, "EDUBOOK1502"),
 		},
 	},
 	{
 	.callback = video_detect_force_native,
 	.ident = "Clevo NL5xNU",
 	.matches = {
 		DMI_MATCH(DMI_BOARD_NAME, "NL5xNU"),
 		},
 	},
 	/*
 	 * The TongFang PF5PU1G, PF4NU1F, PF5NU1G, and PF5LUXG/TUXEDO BA15 Gen10,
 	 * Pulse 14/15 Gen1, and Pulse 15 Gen2 have the same problem as the Clevo
 	 * NL5xRU and NL5xNU/TUXEDO Aura 15 Gen1 and Gen2. See the description
 	 * above.
 	 */
 	{
 	.callback = video_detect_force_native,
 	.ident = "TongFang PF5PU1G",
 	.matches = {
 		DMI_MATCH(DMI_BOARD_NAME, "PF5PU1G"),
 		},
 	},
 	{
 	.callback = video_detect_force_native,
 	.ident = "TongFang PF4NU1F",
 	.matches = {
 		DMI_MATCH(DMI_BOARD_NAME, "PF4NU1F"),
 		},
 	},
 	{
 	.callback = video_detect_force_native,
 	.ident = "TongFang PF4NU1F",
 	.matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "TUXEDO"),
 		DMI_MATCH(DMI_BOARD_NAME, "PULSE1401"),
 		},
 	},
 	{
 	.callback = video_detect_force_native,
 	.ident = "TongFang PF5NU1G",
 	.matches = {
 		DMI_MATCH(DMI_BOARD_NAME, "PF5NU1G"),
 		},
 	},
 	{
 	.callback = video_detect_force_native,
 	.ident = "TongFang PF5NU1G",
 	.matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "TUXEDO"),
 		DMI_MATCH(DMI_BOARD_NAME, "PULSE1501"),
 		},
 	},
 	{
 	.callback = video_detect_force_native,
 	.ident = "TongFang PF5LUXG",
 	.matches = {
 		DMI_MATCH(DMI_BOARD_NAME, "PF5LUXG"),
 		},
 	},
 	/*
 	 * More Tongfang devices with the same issue as the Clevo NL5xRU and
 	 * NL5xNU/TUXEDO Aura 15 Gen1 and Gen2. See the description above.
 	 */
 	{
 	.callback = video_detect_force_native,
 	.ident = "TongFang GKxNRxx",
 	.matches = {
 		DMI_MATCH(DMI_BOARD_NAME, "GKxNRxx"),
 		},
 	},
 	{
 	.callback = video_detect_force_native,
 	.ident = "TongFang GKxNRxx",
 	.matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "TUXEDO"),
 		DMI_MATCH(DMI_BOARD_NAME, "POLARIS1501A1650TI"),
 		},
 	},
 	{
 	.callback = video_detect_force_native,
 	.ident = "TongFang GKxNRxx",
 	.matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "TUXEDO"),
 		DMI_MATCH(DMI_BOARD_NAME, "POLARIS1501A2060"),
 		},
 	},
 	{
 	.callback = video_detect_force_native,
 	.ident = "TongFang GKxNRxx",
 	.matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "TUXEDO"),
 		DMI_MATCH(DMI_BOARD_NAME, "POLARIS1701A1650TI"),
 		},
 	},
 	{
 	.callback = video_detect_force_native,
 	.ident = "TongFang GKxNRxx",
 	.matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "TUXEDO"),
 		DMI_MATCH(DMI_BOARD_NAME, "POLARIS1701A2060"),
 		},
 	},
 	{
 	.callback = video_detect_force_native,
 	.ident = "TongFang GMxNGxx",
 	.matches = {
 		DMI_MATCH(DMI_BOARD_NAME, "GMxNGxx"),
 		},
 	},
 	{
 	.callback = video_detect_force_native,
 	.ident = "TongFang GMxZGxx",
 	.matches = {
 		DMI_MATCH(DMI_BOARD_NAME, "GMxZGxx"),
 		},
 	},
 	{
 	.callback = video_detect_force_native,
 	.ident = "TongFang GMxRGxx",
 	.matches = {
 		DMI_MATCH(DMI_BOARD_NAME, "GMxRGxx"),
 		},
 	},
 	/*
 	 * Desktops which falsely report a backlight and which our heuristics
 	 * for this do not catch.
 	 */
 	{
 	 .callback = video_detect_force_none,
 	 .ident = "Dell OptiPlex 9020M",
 	 .matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 		DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 9020M"),
 		},
 	},
 	{
 	 .callback = video_detect_force_none,
 	 .ident = "MSI MS-7721",
 	 .matches = {
 		DMI_MATCH(DMI_SYS_VENDOR, "MSI"),
 		DMI_MATCH(DMI_PRODUCT_NAME, "MS-7721"),
 		},
 	},
 	{ },
 };

 /* This uses a workqueue to avoid various locking ordering issues */
 static void acpi_video_backlight_notify_work(struct work_struct *work)
 {
 	if (acpi_video_get_backlight_type() != acpi_backlight_video)
 		acpi_video_unregister_backlight();
 }

 static int acpi_video_backlight_notify(struct notifier_block *nb,
 				       unsigned long val, void *bd)
 {
 	struct backlight_device *backlight = bd;

 	/* A raw bl registering may change video -> native */
 	if (backlight->props.type == BACKLIGHT_RAW &&
 	    val == BACKLIGHT_REGISTERED)
 		schedule_work(&backlight_notify_work);

 	return NOTIFY_OK;
 }

 /*
  * Determine which type of backlight interface to use on this system,
  * First check cmdline, then dmi quirks, then do autodetect.
  *
  * The autodetect order is:
  * 1) Is the acpi-video backlight interface supported ->
  *  no, use a vendor interface
  * 2) Is this a win8 "ready" BIOS and do we have a native interface ->
  *  yes, use a native interface
  * 3) Else use the acpi-video interface
  *
  * Arguably the native on win8 check should be done first, but that would
  * be a behavior change, which may causes issues.
  */
 enum acpi_backlight_type acpi_video_get_backlight_type(void)
 {
 	static DEFINE_MUTEX(init_mutex);
 	static bool init_done;
 	static long video_caps;

 	/* Parse cmdline, dmi and acpi only once */
 	mutex_lock(&init_mutex);
 	if (!init_done) {
 		acpi_video_parse_cmdline();
 		dmi_check_system(video_detect_dmi_table);
 		acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
 				    ACPI_UINT32_MAX, find_video, NULL,
 				    &video_caps, NULL);
 		INIT_WORK(&backlight_notify_work,
 			  acpi_video_backlight_notify_work);
 		backlight_nb.notifier_call = acpi_video_backlight_notify;
 		backlight_nb.priority = 0;
 		if (backlight_register_notifier(&backlight_nb) == 0)
 			backlight_notifier_registered = true;
 		init_done = true;
 	}
 	mutex_unlock(&init_mutex);

 	if (acpi_backlight_cmdline != acpi_backlight_undef)
 		return acpi_backlight_cmdline;

 	if (acpi_backlight_dmi != acpi_backlight_undef)
 		return acpi_backlight_dmi;

 	if (!(video_caps & ACPI_VIDEO_BACKLIGHT))
 		return acpi_backlight_vendor;

 	if (acpi_osi_is_win8() && backlight_device_get_by_type(BACKLIGHT_RAW))
 		return acpi_backlight_native;

 	return acpi_backlight_video;
 }
 EXPORT_SYMBOL(acpi_video_get_backlight_type);

 /*
  * Set the preferred backlight interface type based on DMI info.
  * This function allows DMI blacklists to be implemented by external
  * platform drivers instead of putting a big blacklist in video_detect.c
  */
 void acpi_video_set_dmi_backlight_type(enum acpi_backlight_type type)
 {
 	acpi_backlight_dmi = type;
 	/* Remove acpi-video backlight interface if it is no longer desired */
 	if (acpi_video_get_backlight_type() != acpi_backlight_video)
 		acpi_video_unregister_backlight();
 }
 EXPORT_SYMBOL(acpi_video_set_dmi_backlight_type);

 void __exit acpi_video_detect_exit(void)
 {
 	if (backlight_notifier_registered)
 		backlight_unregister_notifier(&backlight_nb);
 }
	/*
	* Copyright (C) 2015 Red Hat Inc.
	* Hans de Goede <hdegoede@redhat.com>
	* Copyright (C) 2008 SuSE Linux Products GmbH
	* Thomas Renninger <trenn@suse.de>
	*
	* May be copied or modified under the terms of the GNU General Public License
	*
	* video_detect.c:
	* After PCI devices are glued with ACPI devices
	* acpi_get_pci_dev() can be called to identify ACPI graphics
	* devices for which a real graphics card is plugged in
	*
	* Depending on whether ACPI graphics extensions (cmp. ACPI spec Appendix B)
	* are available, video.ko should be used to handle the device.
	*
	* Otherwise vendor specific drivers like thinkpad_acpi, asus-laptop,
	* sony_acpi,... can take care about backlight brightness.
	*
	* Backlight drivers can use acpi_video_get_backlight_type() to determine
	* which driver should handle the backlight.
	*
	* If CONFIG_ACPI_VIDEO is neither set as "compiled in" (y) nor as a module (m)
	* this file will not be compiled and acpi_video_get_backlight_type() will
	* always return acpi_backlight_vendor.
	*/

	#include <linux/export.h>
	#include <linux/acpi.h>
	#include <linux/backlight.h>
	#include <linux/dmi.h>
	#include <linux/module.h>
	#include <linux/pci.h>
	#include <linux/types.h>
	#include <linux/workqueue.h>
	#include <acpi/video.h>

	ACPI_MODULE_NAME("video");
	#define _COMPONENT ACPI_VIDEO_COMPONENT

	void acpi_video_unregister_backlight(void);

	static bool backlight_notifier_registered;
	static struct notifier_block backlight_nb;
	static struct work_struct backlight_notify_work;

	static enum acpi_backlight_type acpi_backlight_cmdline = acpi_backlight_undef;
	static enum acpi_backlight_type acpi_backlight_dmi = acpi_backlight_undef;

	static void acpi_video_parse_cmdline(void)
	{
	if (!strcmp("vendor", acpi_video_backlight_string))
	acpi_backlight_cmdline = acpi_backlight_vendor;
	if (!strcmp("video", acpi_video_backlight_string))
	acpi_backlight_cmdline = acpi_backlight_video;
	if (!strcmp("native", acpi_video_backlight_string))
	acpi_backlight_cmdline = acpi_backlight_native;
	if (!strcmp("none", acpi_video_backlight_string))
	acpi_backlight_cmdline = acpi_backlight_none;
	}

	static acpi_status
	find_video(acpi_handle handle, u32 lvl, void context, void *rv)
	{
	long *cap = context;
	struct pci_dev *dev;
	struct acpi_device *acpi_dev;

	static const struct acpi_device_id video_ids[] = {
	{ACPI_VIDEO_HID, 0},
	{"", 0},
	};
	if (acpi_bus_get_device(handle, &acpi_dev))
	return AE_OK;

	if (!acpi_match_device_ids(acpi_dev, video_ids)) {
	dev = acpi_get_pci_dev(handle);
	if (!dev)
	return AE_OK;
	pci_dev_put(dev);
	*cap \|= acpi_is_video_device(handle);
	}
	return AE_OK;
	}

	/* Force to use vendor driver when the ACPI device is known to be
	* buggy */
	static int video_detect_force_vendor(const struct dmi_system_id *d)
	{
	acpi_backlight_dmi = acpi_backlight_vendor;
	return 0;
	}

	static int video_detect_force_video(const struct dmi_system_id *d)
	{
	acpi_backlight_dmi = acpi_backlight_video;
	return 0;
	}

	static int video_detect_force_native(const struct dmi_system_id *d)
	{
	acpi_backlight_dmi = acpi_backlight_native;
	return 0;
	}

	static int video_detect_force_none(const struct dmi_system_id *d)
	{
	acpi_backlight_dmi = acpi_backlight_none;
	return 0;
	}

	static const struct dmi_system_id video_detect_dmi_table[] = {
	/* On Samsung X360, the BIOS will set a flag (VDRV) if generic
	* ACPI backlight device is used. This flag will definitively break
	* the backlight interface (even the vendor interface) untill next
	* reboot. It's why we should prevent video.ko from being used here
	* and we can't rely on a later call to acpi_video_unregister().
	*/
	{
	.callback = video_detect_force_vendor,
	.ident = "X360",
	.matches = {
	DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."),
	DMI_MATCH(DMI_PRODUCT_NAME, "X360"),
	DMI_MATCH(DMI_BOARD_NAME, "X360"),
	},
	},
	{
	.callback = video_detect_force_vendor,
	.ident = "Asus UL30VT",
	.matches = {
	DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK Computer Inc."),
	DMI_MATCH(DMI_PRODUCT_NAME, "UL30VT"),
	},
	},
	{
	.callback = video_detect_force_vendor,
	.ident = "Asus UL30A",
	.matches = {
	DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK Computer Inc."),
	DMI_MATCH(DMI_PRODUCT_NAME, "UL30A"),
	},
	},

	/*
	* These models have a working acpi_video backlight control, and using
	* native backlight causes a regression where backlight does not work
	* when userspace is not handling brightness key events. Disable
	* native_backlight on these to fix this:
	* https://bugzilla.kernel.org/show_bug.cgi?id=81691
	*/
	{
	.callback = video_detect_force_video,
	.ident = "ThinkPad T420",
	.matches = {
	DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
	DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad T420"),
	},
	},
	{
	.callback = video_detect_force_video,
	.ident = "ThinkPad T520",
	.matches = {
	DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
	DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad T520"),
	},
	},
	{
	.callback = video_detect_force_video,
	.ident = "ThinkPad X201s",
	.matches = {
	DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
	DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad X201s"),
	},
	},
	{
	.callback = video_detect_force_video,
	.ident = "ThinkPad X201T",
	.matches = {
	DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
	DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad X201T"),
	},
	},

	/* The native backlight controls do not work on some older machines */
	{
	/* https://bugs.freedesktop.org/show_bug.cgi?id=81515 */
	.callback = video_detect_force_video,
	.ident = "HP ENVY 15 Notebook",
	.matches = {
	DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
	DMI_MATCH(DMI_PRODUCT_NAME, "HP ENVY 15 Notebook PC"),
	},
	},
	{
	.callback = video_detect_force_video,
	.ident = "SAMSUNG 870Z5E/880Z5E/680Z5E",
	.matches = {
	DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."),
	DMI_MATCH(DMI_PRODUCT_NAME, "870Z5E/880Z5E/680Z5E"),
	},
	},
	{
	.callback = video_detect_force_video,
	.ident = "SAMSUNG 370R4E/370R4V/370R5E/3570RE/370R5V",
	.matches = {
	DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."),
	DMI_MATCH(DMI_PRODUCT_NAME,
	"370R4E/370R4V/370R5E/3570RE/370R5V"),
	},
	},
	{
	/* https://bugzilla.redhat.com/show_bug.cgi?id=1186097 */
	.callback = video_detect_force_video,
	.ident = "SAMSUNG 3570R/370R/470R/450R/510R/4450RV",
	.matches = {
	DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."),
	DMI_MATCH(DMI_PRODUCT_NAME,
	"3570R/370R/470R/450R/510R/4450RV"),
	},
	},
	{
	/* https://bugzilla.redhat.com/show_bug.cgi?id=1557060 */
	.callback = video_detect_force_video,
	.ident = "SAMSUNG 670Z5E",
	.matches = {
	DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."),
	DMI_MATCH(DMI_PRODUCT_NAME, "670Z5E"),
	},
	},
	{
	/* https://bugzilla.redhat.com/show_bug.cgi?id=1094948 */
	.callback = video_detect_force_video,
	.ident = "SAMSUNG 730U3E/740U3E",
	.matches = {
	DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."),
	DMI_MATCH(DMI_PRODUCT_NAME, "730U3E/740U3E"),
	},
	},
	{
	/* https://bugs.freedesktop.org/show_bug.cgi?id=87286 */
	.callback = video_detect_force_video,
	.ident = "SAMSUNG 900X3C/900X3D/900X3E/900X4C/900X4D",
	.matches = {
	DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."),
	DMI_MATCH(DMI_PRODUCT_NAME,
	"900X3C/900X3D/900X3E/900X4C/900X4D"),
	},
	},
	{
	/* https://bugzilla.redhat.com/show_bug.cgi?id=1272633 */
	.callback = video_detect_force_video,
	.ident = "Dell XPS14 L421X",
	.matches = {
	DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
	DMI_MATCH(DMI_PRODUCT_NAME, "XPS L421X"),
	},
	},
	{
	/* https://bugzilla.redhat.com/show_bug.cgi?id=1163574 */
	.callback = video_detect_force_video,
	.ident = "Dell XPS15 L521X",
	.matches = {
	DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
	DMI_MATCH(DMI_PRODUCT_NAME, "XPS L521X"),
	},
	},
	{
	/* https://bugzilla.kernel.org/show_bug.cgi?id=108971 */
	.callback = video_detect_force_video,
	.ident = "SAMSUNG 530U4E/540U4E",
	.matches = {
	DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."),
	DMI_MATCH(DMI_PRODUCT_NAME, "530U4E/540U4E"),
	},
	},
	/* https://bugs.launchpad.net/bugs/1894667 */
	{
	.callback = video_detect_force_video,
	.ident = "HP 635 Notebook",
	.matches = {
	DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
	DMI_MATCH(DMI_PRODUCT_NAME, "HP 635 Notebook PC"),
	},
	},

	/* Non win8 machines which need native backlight nevertheless */
	{
	/* https://bugzilla.redhat.com/show_bug.cgi?id=1201530 */
	.callback = video_detect_force_native,
	.ident = "Lenovo Ideapad S405",
	.matches = {
	DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
	DMI_MATCH(DMI_BOARD_NAME, "Lenovo IdeaPad S405"),
	},
	},
	{
	/* https://bugzilla.redhat.com/show_bug.cgi?id=1187004 */
	.callback = video_detect_force_native,
	.ident = "Lenovo Ideapad Z570",
	.matches = {
	DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
	DMI_MATCH(DMI_PRODUCT_VERSION, "Ideapad Z570"),
	},
	},
	{
	/* https://bugzilla.redhat.com/show_bug.cgi?id=1217249 */
	.callback = video_detect_force_native,
	.ident = "Apple MacBook Pro 12,1",
	.matches = {
	DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
	DMI_MATCH(DMI_PRODUCT_NAME, "MacBookPro12,1"),
	},
	},
	{
	.callback = video_detect_force_native,
	.ident = "Dell Vostro V131",
	.matches = {
	DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
	DMI_MATCH(DMI_PRODUCT_NAME, "Vostro V131"),
	},
	},
	{
	/* https://bugzilla.redhat.com/show_bug.cgi?id=1123661 */
	.callback = video_detect_force_native,
	.ident = "Dell XPS 17 L702X",
	.matches = {
	DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
	DMI_MATCH(DMI_PRODUCT_NAME, "Dell System XPS L702X"),
	},
	},
	{
	.callback = video_detect_force_native,
	.ident = "Dell Precision 7510",
	.matches = {
	DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
	DMI_MATCH(DMI_PRODUCT_NAME, "Precision 7510"),
	},
	},
	{
	.callback = video_detect_force_native,
	.ident = "Acer Aspire 5738z",
	.matches = {
	DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
	DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5738"),
	DMI_MATCH(DMI_BOARD_NAME, "JV50"),
	},
	},
	{
	/* https://bugzilla.kernel.org/show_bug.cgi?id=207835 */
	.callback = video_detect_force_native,
	.ident = "Acer TravelMate 5735Z",
	.matches = {
	DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
	DMI_MATCH(DMI_PRODUCT_NAME, "TravelMate 5735Z"),
	DMI_MATCH(DMI_BOARD_NAME, "BA51_MV"),
	},
	},
	/*
	* Clevo NL5xRU and NL5xNU/TUXEDO Aura 15 Gen1 and Gen2 have both a
	* working native and video interface. However the default detection
	* mechanism first registers the video interface before unregistering
	* it again and switching to the native interface during boot. This
	* results in a dangling SBIOS request for backlight change for some
	* reason, causing the backlight to switch to ~2% once per boot on the
	* first power cord connect or disconnect event. Setting the native
	* interface explicitly circumvents this buggy behaviour, by avoiding
	* the unregistering process.
	*/
	{
	.callback = video_detect_force_native,
	.ident = "Clevo NL5xRU",
	.matches = {
	DMI_MATCH(DMI_BOARD_NAME, "NL5xRU"),
	},
	},
	{
	.callback = video_detect_force_native,
	.ident = "Clevo NL5xRU",
	.matches = {
	DMI_MATCH(DMI_SYS_VENDOR, "TUXEDO"),
	DMI_MATCH(DMI_BOARD_NAME, "AURA1501"),
	},
	},
	{
	.callback = video_detect_force_native,
	.ident = "Clevo NL5xRU",
	.matches = {
	DMI_MATCH(DMI_SYS_VENDOR, "TUXEDO"),
	DMI_MATCH(DMI_BOARD_NAME, "EDUBOOK1502"),
	},
	},
	{
	.callback = video_detect_force_native,
	.ident = "Clevo NL5xNU",
	.matches = {
	DMI_MATCH(DMI_BOARD_NAME, "NL5xNU"),
	},
	},
	/*
	* The TongFang PF5PU1G, PF4NU1F, PF5NU1G, and PF5LUXG/TUXEDO BA15 Gen10,
	* Pulse 14/15 Gen1, and Pulse 15 Gen2 have the same problem as the Clevo
	* NL5xRU and NL5xNU/TUXEDO Aura 15 Gen1 and Gen2. See the description
	* above.
	*/
	{
	.callback = video_detect_force_native,
	.ident = "TongFang PF5PU1G",
	.matches = {
	DMI_MATCH(DMI_BOARD_NAME, "PF5PU1G"),
	},
	},
	{
	.callback = video_detect_force_native,
	.ident = "TongFang PF4NU1F",
	.matches = {
	DMI_MATCH(DMI_BOARD_NAME, "PF4NU1F"),
	},
	},
	{
	.callback = video_detect_force_native,
	.ident = "TongFang PF4NU1F",
	.matches = {
	DMI_MATCH(DMI_SYS_VENDOR, "TUXEDO"),
	DMI_MATCH(DMI_BOARD_NAME, "PULSE1401"),
	},
	},
	{
	.callback = video_detect_force_native,
	.ident = "TongFang PF5NU1G",
	.matches = {
	DMI_MATCH(DMI_BOARD_NAME, "PF5NU1G"),
	},
	},
	{
	.callback = video_detect_force_native,
	.ident = "TongFang PF5NU1G",
	.matches = {
	DMI_MATCH(DMI_SYS_VENDOR, "TUXEDO"),
	DMI_MATCH(DMI_BOARD_NAME, "PULSE1501"),
	},
	},
	{
	.callback = video_detect_force_native,
	.ident = "TongFang PF5LUXG",
	.matches = {
	DMI_MATCH(DMI_BOARD_NAME, "PF5LUXG"),
	},
	},
	/*
	* More Tongfang devices with the same issue as the Clevo NL5xRU and
	* NL5xNU/TUXEDO Aura 15 Gen1 and Gen2. See the description above.
	*/
	{
	.callback = video_detect_force_native,
	.ident = "TongFang GKxNRxx",
	.matches = {
	DMI_MATCH(DMI_BOARD_NAME, "GKxNRxx"),
	},
	},
	{
	.callback = video_detect_force_native,
	.ident = "TongFang GKxNRxx",
	.matches = {
	DMI_MATCH(DMI_SYS_VENDOR, "TUXEDO"),
	DMI_MATCH(DMI_BOARD_NAME, "POLARIS1501A1650TI"),
	},
	},
	{
	.callback = video_detect_force_native,
	.ident = "TongFang GKxNRxx",
	.matches = {
	DMI_MATCH(DMI_SYS_VENDOR, "TUXEDO"),
	DMI_MATCH(DMI_BOARD_NAME, "POLARIS1501A2060"),
	},
	},
	{
	.callback = video_detect_force_native,
	.ident = "TongFang GKxNRxx",
	.matches = {
	DMI_MATCH(DMI_SYS_VENDOR, "TUXEDO"),
	DMI_MATCH(DMI_BOARD_NAME, "POLARIS1701A1650TI"),
	},
	},
	{
	.callback = video_detect_force_native,
	.ident = "TongFang GKxNRxx",
	.matches = {
	DMI_MATCH(DMI_SYS_VENDOR, "TUXEDO"),
	DMI_MATCH(DMI_BOARD_NAME, "POLARIS1701A2060"),
	},
	},
	{
	.callback = video_detect_force_native,
	.ident = "TongFang GMxNGxx",
	.matches = {
	DMI_MATCH(DMI_BOARD_NAME, "GMxNGxx"),
	},
	},
	{
	.callback = video_detect_force_native,
	.ident = "TongFang GMxZGxx",
	.matches = {
	DMI_MATCH(DMI_BOARD_NAME, "GMxZGxx"),
	},
	},
	{
	.callback = video_detect_force_native,
	.ident = "TongFang GMxRGxx",
	.matches = {
	DMI_MATCH(DMI_BOARD_NAME, "GMxRGxx"),
	},
	},
	/*
	* Desktops which falsely report a backlight and which our heuristics
	* for this do not catch.
	*/
	{
	.callback = video_detect_force_none,
	.ident = "Dell OptiPlex 9020M",
	.matches = {
	DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
	DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 9020M"),
	},
	},
	{
	.callback = video_detect_force_none,
	.ident = "MSI MS-7721",
	.matches = {
	DMI_MATCH(DMI_SYS_VENDOR, "MSI"),
	DMI_MATCH(DMI_PRODUCT_NAME, "MS-7721"),
	},
	},
	{ },
	};

	/* This uses a workqueue to avoid various locking ordering issues */
	static void acpi_video_backlight_notify_work(struct work_struct *work)
	{
	if (acpi_video_get_backlight_type() != acpi_backlight_video)
	acpi_video_unregister_backlight();
	}

	static int acpi_video_backlight_notify(struct notifier_block *nb,
	unsigned long val, void *bd)
	{
	struct backlight_device *backlight = bd;

	/* A raw bl registering may change video -> native */
	if (backlight->props.type == BACKLIGHT_RAW &&
	val == BACKLIGHT_REGISTERED)
	schedule_work(&backlight_notify_work);

	return NOTIFY_OK;
	}

	/*
	* Determine which type of backlight interface to use on this system,
	* First check cmdline, then dmi quirks, then do autodetect.
	*
	* The autodetect order is:
	* 1) Is the acpi-video backlight interface supported ->
	* no, use a vendor interface
	* 2) Is this a win8 "ready" BIOS and do we have a native interface ->
	* yes, use a native interface
	* 3) Else use the acpi-video interface
	*
	* Arguably the native on win8 check should be done first, but that would
	* be a behavior change, which may causes issues.
	*/
	enum acpi_backlight_type acpi_video_get_backlight_type(void)
	{
	static DEFINE_MUTEX(init_mutex);
	static bool init_done;
	static long video_caps;

	/* Parse cmdline, dmi and acpi only once */
	mutex_lock(&init_mutex);
	if (!init_done) {
	acpi_video_parse_cmdline();
	dmi_check_system(video_detect_dmi_table);
	acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
	ACPI_UINT32_MAX, find_video, NULL,
	&video_caps, NULL);
	INIT_WORK(&backlight_notify_work,
	acpi_video_backlight_notify_work);
	backlight_nb.notifier_call = acpi_video_backlight_notify;
	backlight_nb.priority = 0;
	if (backlight_register_notifier(&backlight_nb) == 0)
	backlight_notifier_registered = true;
	init_done = true;
	}
	mutex_unlock(&init_mutex);

	if (acpi_backlight_cmdline != acpi_backlight_undef)
	return acpi_backlight_cmdline;

	if (acpi_backlight_dmi != acpi_backlight_undef)
	return acpi_backlight_dmi;

	if (!(video_caps & ACPI_VIDEO_BACKLIGHT))
	return acpi_backlight_vendor;

	if (acpi_osi_is_win8() && backlight_device_get_by_type(BACKLIGHT_RAW))
	return acpi_backlight_native;

	return acpi_backlight_video;
	}
	EXPORT_SYMBOL(acpi_video_get_backlight_type);

	/*
	* Set the preferred backlight interface type based on DMI info.
	* This function allows DMI blacklists to be implemented by external
	* platform drivers instead of putting a big blacklist in video_detect.c
	*/
	void acpi_video_set_dmi_backlight_type(enum acpi_backlight_type type)
	{
	acpi_backlight_dmi = type;
	/* Remove acpi-video backlight interface if it is no longer desired */
	if (acpi_video_get_backlight_type() != acpi_backlight_video)
	acpi_video_unregister_backlight();
	}
	EXPORT_SYMBOL(acpi_video_set_dmi_backlight_type);

	void __exit acpi_video_detect_exit(void)
	{
	if (backlight_notifier_registered)
	backlight_unregister_notifier(&backlight_nb);
	}