Merge branch 'acpi-video'

* acpi-video: (38 commits)
  ACPI / video: Make acpi_video_unregister_backlight() private
  acpi-video-detect: Remove old API
  toshiba-acpi: Port to new backlight interface selection API
  thinkpad-acpi: Port to new backlight interface selection API
  sony-laptop: Port to new backlight interface selection API
  samsung-laptop: Port to new backlight interface selection API
  msi-wmi: Port to new backlight interface selection API
  msi-laptop: Port to new backlight interface selection API
  intel-oaktrail: Port to new backlight interface selection API
  ideapad-laptop: Port to new backlight interface selection API
  fujitsu-laptop: Port to new backlight interface selection API
  eeepc-laptop: Port to new backlight interface selection API
  dell-wmi: Port to new backlight interface selection API
  dell-laptop: Port to new backlight interface selection API
  compal-laptop: Port to new backlight interface selection API
  asus-wmi: Port to new backlight interface selection API
  asus-laptop: Port to new backlight interface selection API
  apple-gmux: Port to new backlight interface selection API
  acer-wmi: Port to new backlight interface selection API
  ACPI / video: Fix acpi_video _register vs _unregister_backlight race
  ...

7 files changed, 359 insertions, 422 deletions

diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
index 8a063e276530..73d840bef455 100644
--- a/drivers/acpi/Makefile
+++ b/drivers/acpi/Makefile
@@ -52,9 +52,6 @@ acpi-$(CONFIG_X86)		+= acpi_cmos_rtc.o
 acpi-$(CONFIG_DEBUG_FS)		+= debugfs.o
 acpi-$(CONFIG_ACPI_NUMA)	+= numa.o
 acpi-$(CONFIG_ACPI_PROCFS_POWER) += cm_sbs.o
-ifdef CONFIG_ACPI_VIDEO
-acpi-y				+= video_detect.o
-endif
 acpi-y				+= acpi_lpat.o
 acpi-$(CONFIG_ACPI_GENERIC_GSI) += gsi.o
 
@@ -95,3 +92,5 @@ obj-$(CONFIG_ACPI_EXTLOG)	+= acpi_extlog.o
 obj-$(CONFIG_PMIC_OPREGION)	+= pmic/intel_pmic.o
 obj-$(CONFIG_CRC_PMIC_OPREGION) += pmic/intel_pmic_crc.o
 obj-$(CONFIG_XPOWER_PMIC_OPREGION) += pmic/intel_pmic_xpower.o
+
+video-objs			+= acpi_video.o video_detect.o
diff --git a/drivers/acpi/video.c b/drivers/acpi/acpi_video.c
index cc79d3fedfb2..8c2fe2f2f9fd 100644
--- a/drivers/acpi/video.c
+++ b/drivers/acpi/acpi_video.c
@@ -43,7 +43,7 @@
 #include <acpi/video.h>
 #include <asm/uaccess.h>
 
-#include "internal.h"
+#define PREFIX "ACPI: "
 
 #define ACPI_VIDEO_BUS_NAME		"Video Bus"
 #define ACPI_VIDEO_DEVICE_NAME		"Video Device"
@@ -78,26 +78,17 @@ module_param(brightness_switch_enabled, bool, 0644);
 static bool allow_duplicates;
 module_param(allow_duplicates, bool, 0644);
 
-/*
- * For Windows 8 systems: used to decide if video module
- * should skip registering backlight interface of its own.
- */
-enum {
-	NATIVE_BACKLIGHT_NOT_SET = -1,
-	NATIVE_BACKLIGHT_OFF,
-	NATIVE_BACKLIGHT_ON,
-};
-
-static int use_native_backlight_param = NATIVE_BACKLIGHT_NOT_SET;
-module_param_named(use_native_backlight, use_native_backlight_param, int, 0444);
-static int use_native_backlight_dmi = NATIVE_BACKLIGHT_NOT_SET;
+static int disable_backlight_sysfs_if = -1;
+module_param(disable_backlight_sysfs_if, int, 0444);
 
 static int register_count;
+static DEFINE_MUTEX(register_count_mutex);
 static struct mutex video_list_lock;
 static struct list_head video_bus_head;
 static int acpi_video_bus_add(struct acpi_device *device);
 static int acpi_video_bus_remove(struct acpi_device *device);
 static void acpi_video_bus_notify(struct acpi_device *device, u32 event);
+void acpi_video_detect_exit(void);
 
 static const struct acpi_device_id video_device_ids[] = {
 	{ACPI_VIDEO_HID, 0},
@@ -157,7 +148,6 @@ struct acpi_video_enumerated_device {
 struct acpi_video_bus {
 	struct acpi_device *device;
 	bool backlight_registered;
-	bool backlight_notifier_registered;
 	u8 dos_setting;
 	struct acpi_video_enumerated_device *attached_array;
 	u8 attached_count;
@@ -170,7 +160,6 @@ struct acpi_video_bus {
 	struct input_dev *input;
 	char phys[32];	/* for input device */
 	struct notifier_block pm_nb;
-	struct notifier_block backlight_nb;
 };
 
 struct acpi_video_device_flags {
@@ -241,24 +230,6 @@ static int acpi_video_get_next_level(struct acpi_video_device *device,
 				     u32 level_current, u32 event);
 static void acpi_video_switch_brightness(struct work_struct *work);
 
-static bool acpi_video_use_native_backlight(void)
-{
-	if (use_native_backlight_param != NATIVE_BACKLIGHT_NOT_SET)
-		return use_native_backlight_param;
-	else if (use_native_backlight_dmi != NATIVE_BACKLIGHT_NOT_SET)
-		return use_native_backlight_dmi;
-	return acpi_osi_is_win8();
-}
-
-bool acpi_video_verify_backlight_support(void)
-{
-	if (acpi_video_use_native_backlight() &&
-	    backlight_device_registered(BACKLIGHT_RAW))
-		return false;
-	return acpi_video_backlight_support();
-}
-EXPORT_SYMBOL_GPL(acpi_video_verify_backlight_support);
-
 /* backlight device sysfs support */
 static int acpi_video_get_brightness(struct backlight_device *bd)
 {
@@ -413,25 +384,21 @@ acpi_video_device_lcd_set_level(struct acpi_video_device *device, int level)
  */
 
 static int bqc_offset_aml_bug_workaround;
-static int __init video_set_bqc_offset(const struct dmi_system_id *d)
+static int video_set_bqc_offset(const struct dmi_system_id *d)
 {
 	bqc_offset_aml_bug_workaround = 9;
 	return 0;
 }
 
-static int __init video_disable_native_backlight(const struct dmi_system_id *d)
-{
-	use_native_backlight_dmi = NATIVE_BACKLIGHT_OFF;
-	return 0;
-}
-
-static int __init video_enable_native_backlight(const struct dmi_system_id *d)
+static int video_disable_backlight_sysfs_if(
+	const struct dmi_system_id *d)
 {
-	use_native_backlight_dmi = NATIVE_BACKLIGHT_ON;
+	if (disable_backlight_sysfs_if == -1)
+		disable_backlight_sysfs_if = 1;
 	return 0;
 }
 
-static struct dmi_system_id video_dmi_table[] __initdata = {
+static struct dmi_system_id video_dmi_table[] = {
 	/*
 	 * Broken _BQC workaround http://bugzilla.kernel.org/show_bug.cgi?id=13121
 	 */
@@ -477,110 +444,19 @@ static struct dmi_system_id video_dmi_table[] __initdata = {
 	},
 
 	/*
-	 * 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
+	 * Some machines have a broken acpi-video interface for brightness
+	 * control, but still need an acpi_video_device_lcd_set_level() call
+	 * on resume to turn the backlight power on.  We Enable backlight
+	 * control on these systems, but do not register a backlight sysfs
+	 * as brightness control does not work.
 	 */
 	{
-	 .callback = video_disable_native_backlight,
-	 .ident = "ThinkPad T420",
-	 .matches = {
-		DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
-		DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad T420"),
-		},
-	},
-	{
-	 .callback = video_disable_native_backlight,
-	 .ident = "ThinkPad T520",
-	 .matches = {
-		DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
-		DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad T520"),
-		},
-	},
-	{
-	 .callback = video_disable_native_backlight,
-	 .ident = "ThinkPad X201s",
-	 .matches = {
-		DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
-		DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad X201s"),
-		},
-	},
-
-	/* The native backlight controls do not work on some older machines */
-	{
-	 /* https://bugs.freedesktop.org/show_bug.cgi?id=81515 */
-	 .callback = video_disable_native_backlight,
-	 .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_disable_native_backlight,
-	 .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_disable_native_backlight,
-	 .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_disable_native_backlight,
-	 .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=1094948 */
-	 .callback = video_disable_native_backlight,
-	 .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_disable_native_backlight,
-	 .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=1163574 */
-	 .callback = video_disable_native_backlight,
-	 .ident = "Dell XPS15 L521X",
+	 /* https://bugs.freedesktop.org/show_bug.cgi?id=82634 */
+	 .callback = video_disable_backlight_sysfs_if,
+	 .ident = "Toshiba Portege R830",
 	 .matches = {
-		DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
-		DMI_MATCH(DMI_PRODUCT_NAME, "XPS L521X"),
-		},
-	},
-
-	/* Non win8 machines which need native backlight nevertheless */
-	{
-	 /* https://bugzilla.redhat.com/show_bug.cgi?id=1187004 */
-	 .callback = video_enable_native_backlight,
-	 .ident = "Lenovo Ideapad Z570",
-	 .matches = {
-		DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
-		DMI_MATCH(DMI_PRODUCT_NAME, "102434U"),
+		DMI_MATCH(DMI_SYS_VENDOR, "TOSHIBA"),
+		DMI_MATCH(DMI_PRODUCT_NAME, "PORTEGE R830"),
 		},
 	},
 	{}
@@ -1382,7 +1258,7 @@ acpi_video_switch_brightness(struct work_struct *work)
 	int result = -EINVAL;
 
 	/* no warning message if acpi_backlight=vendor or a quirk is used */
-	if (!acpi_video_verify_backlight_support())
+	if (!device->backlight)
 		return;
 
 	if (!device->brightness)
@@ -1657,8 +1533,9 @@ static int acpi_video_resume(struct notifier_block *nb,
 
 	for (i = 0; i < video->attached_count; i++) {
 		video_device = video->attached_array[i].bind_info;
-		if (video_device && video_device->backlight)
-			acpi_video_set_brightness(video_device->backlight);
+		if (video_device && video_device->brightness)
+			acpi_video_device_lcd_set_level(video_device,
+					video_device->brightness->curr);
 	}
 
 	return NOTIFY_OK;
@@ -1707,6 +1584,10 @@ static void acpi_video_dev_register_backlight(struct acpi_video_device *device)
 	result = acpi_video_init_brightness(device);
 	if (result)
 		return;
+
+	if (disable_backlight_sysfs_if > 0)
+		return;
+
 	name = kasprintf(GFP_KERNEL, "acpi_video%d", count);
 	if (!name)
 		return;
@@ -1729,8 +1610,10 @@ static void acpi_video_dev_register_backlight(struct acpi_video_device *device)
 						      &acpi_backlight_ops,
 						      &props);
 	kfree(name);
-	if (IS_ERR(device->backlight))
+	if (IS_ERR(device->backlight)) {
+		device->backlight = NULL;
 		return;
+	}
 
 	/*
 	 * Save current brightness level in case we have to restore it
@@ -1787,7 +1670,7 @@ static int acpi_video_bus_register_backlight(struct acpi_video_bus *video)
 
 	acpi_video_run_bcl_for_osi(video);
 
-	if (!acpi_video_verify_backlight_support())
+	if (acpi_video_get_backlight_type() != acpi_backlight_video)
 		return 0;
 
 	mutex_lock(&video->device_list_lock);
@@ -1931,56 +1814,6 @@ static void acpi_video_bus_remove_notify_handler(struct acpi_video_bus *video)
 	video->input = NULL;
 }
 
-static int acpi_video_backlight_notify(struct notifier_block *nb,
-					unsigned long val, void *bd)
-{
-	struct backlight_device *backlight = bd;
-	struct acpi_video_bus *video;
-
-	/* acpi_video_verify_backlight_support only cares about raw devices */
-	if (backlight->props.type != BACKLIGHT_RAW)
-		return NOTIFY_DONE;
-
-	video = container_of(nb, struct acpi_video_bus, backlight_nb);
-
-	switch (val) {
-	case BACKLIGHT_REGISTERED:
-		if (!acpi_video_verify_backlight_support())
-			acpi_video_bus_unregister_backlight(video);
-		break;
-	case BACKLIGHT_UNREGISTERED:
-		acpi_video_bus_register_backlight(video);
-		break;
-	}
-
-	return NOTIFY_OK;
-}
-
-static int acpi_video_bus_add_backlight_notify_handler(
-						struct acpi_video_bus *video)
-{
-	int error;
-
-	video->backlight_nb.notifier_call = acpi_video_backlight_notify;
-	video->backlight_nb.priority = 0;
-	error = backlight_register_notifier(&video->backlight_nb);
-	if (error == 0)
-		video->backlight_notifier_registered = true;
-
-	return error;
-}
-
-static int acpi_video_bus_remove_backlight_notify_handler(
-						struct acpi_video_bus *video)
-{
-	if (!video->backlight_notifier_registered)
-		return 0;
-
-	video->backlight_notifier_registered = false;
-
-	return backlight_unregister_notifier(&video->backlight_nb);
-}
-
 static int acpi_video_bus_put_devices(struct acpi_video_bus *video)
 {
 	struct acpi_video_device *dev, *next;
@@ -2062,7 +1895,6 @@ static int acpi_video_bus_add(struct acpi_device *device)
 
 	acpi_video_bus_register_backlight(video);
 	acpi_video_bus_add_notify_handler(video);
-	acpi_video_bus_add_backlight_notify_handler(video);
 
 	return 0;
 
@@ -2086,7 +1918,6 @@ static int acpi_video_bus_remove(struct acpi_device *device)
 
 	video = acpi_driver_data(device);
 
-	acpi_video_bus_remove_backlight_notify_handler(video);
 	acpi_video_bus_remove_notify_handler(video);
 	acpi_video_bus_unregister_backlight(video);
 	acpi_video_bus_put_devices(video);
@@ -2134,22 +1965,25 @@ static int __init intel_opregion_present(void)
 
 int acpi_video_register(void)
 {
-	int ret;
+	int ret = 0;
 
+	mutex_lock(&register_count_mutex);
 	if (register_count) {
 		/*
 		 * if the function of acpi_video_register is already called,
 		 * don't register the acpi_vide_bus again and return no error.
 		 */
-		return 0;
+		goto leave;
 	}
 
 	mutex_init(&video_list_lock);
 	INIT_LIST_HEAD(&video_bus_head);
 
+	dmi_check_system(video_dmi_table);
+
 	ret = acpi_bus_register_driver(&acpi_video_bus);
 	if (ret)
-		return ret;
+		goto leave;
 
 	/*
 	 * When the acpi_video_bus is loaded successfully, increase
@@ -2157,24 +1991,20 @@ int acpi_video_register(void)
 	 */
 	register_count = 1;
 
-	return 0;
+leave:
+	mutex_unlock(&register_count_mutex);
+	return ret;
 }
 EXPORT_SYMBOL(acpi_video_register);
 
 void acpi_video_unregister(void)
 {
-	if (!register_count) {
-		/*
-		 * If the acpi video bus is already unloaded, don't
-		 * unload it again and return directly.
-		 */
-		return;
+	mutex_lock(&register_count_mutex);
+	if (register_count) {
+		acpi_bus_unregister_driver(&acpi_video_bus);
+		register_count = 0;
 	}
-	acpi_bus_unregister_driver(&acpi_video_bus);
-
-	register_count = 0;
-
-	return;
+	mutex_unlock(&register_count_mutex);
 }
 EXPORT_SYMBOL(acpi_video_unregister);
 
@@ -2182,15 +2012,15 @@ void acpi_video_unregister_backlight(void)
 {
 	struct acpi_video_bus *video;
 
-	if (!register_count)
-		return;
-
-	mutex_lock(&video_list_lock);
-	list_for_each_entry(video, &video_bus_head, entry)
-		acpi_video_bus_unregister_backlight(video);
-	mutex_unlock(&video_list_lock);
+	mutex_lock(&register_count_mutex);
+	if (register_count) {
+		mutex_lock(&video_list_lock);
+		list_for_each_entry(video, &video_bus_head, entry)
+			acpi_video_bus_unregister_backlight(video);
+		mutex_unlock(&video_list_lock);
+	}
+	mutex_unlock(&register_count_mutex);
 }
-EXPORT_SYMBOL(acpi_video_unregister_backlight);
 
 /*
  * This is kind of nasty. Hardware using Intel chipsets may require
@@ -2212,8 +2042,6 @@ static int __init acpi_video_init(void)
 	if (acpi_disabled)
 		return 0;
 
-	dmi_check_system(video_dmi_table);
-
 	if (intel_opregion_present())
 		return 0;
 
@@ -2222,6 +2050,7 @@ static int __init acpi_video_init(void)
 
 static void __exit acpi_video_exit(void)
 {
+	acpi_video_detect_exit();
 	acpi_video_unregister();
 
 	return;
diff --git a/drivers/acpi/internal.h b/drivers/acpi/internal.h
index ae919b509e6c..787c629bc9b4 100644
--- a/drivers/acpi/internal.h
+++ b/drivers/acpi/internal.h
@@ -184,13 +184,6 @@ static inline void suspend_nvs_restore(void) {}
 #endif
 
 /*--------------------------------------------------------------------------
-					Video
-  -------------------------------------------------------------------------- */
-#if defined(CONFIG_ACPI_VIDEO) || defined(CONFIG_ACPI_VIDEO_MODULE)
-bool acpi_osi_is_win8(void);
-#endif
-
-/*--------------------------------------------------------------------------
 				Device properties
   -------------------------------------------------------------------------- */
 #define ACPI_DT_NAMESPACE_HID	"PRP0001"
diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c
index a3acd84f2533..a5dc9034efee 100644
--- a/drivers/acpi/osl.c
+++ b/drivers/acpi/osl.c
@@ -1680,6 +1680,12 @@ int acpi_resources_are_enforced(void)
 }
 EXPORT_SYMBOL(acpi_resources_are_enforced);
 
+bool acpi_osi_is_win8(void)
+{
+	return acpi_gbl_osi_data >= ACPI_OSI_WIN_8;
+}
+EXPORT_SYMBOL(acpi_osi_is_win8);
+
 /*
  * Deallocate the memory for a spinlock.
  */
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 0ca4574e89ea..4bbc8f89257f 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -1935,6 +1935,62 @@ bool acpi_dock_match(acpi_handle handle)
 	return acpi_has_method(handle, "_DCK");
 }
 
+static acpi_status
+acpi_backlight_cap_match(acpi_handle handle, u32 level, void *context,
+			  void **return_value)
+{
+	long *cap = context;
+
+	if (acpi_has_method(handle, "_BCM") &&
+	    acpi_has_method(handle, "_BCL")) {
+		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found generic backlight "
+				  "support\n"));
+		*cap |= ACPI_VIDEO_BACKLIGHT;
+		if (!acpi_has_method(handle, "_BQC"))
+			printk(KERN_WARNING FW_BUG PREFIX "No _BQC method, "
+				"cannot determine initial brightness\n");
+		/* We have backlight support, no need to scan further */
+		return AE_CTRL_TERMINATE;
+	}
+	return 0;
+}
+
+/* Returns true if the ACPI object is a video device which can be
+ * handled by video.ko.
+ * The device will get a Linux specific CID added in scan.c to
+ * identify the device as an ACPI graphics device
+ * Be aware that the graphics device may not be physically present
+ * Use acpi_video_get_capabilities() to detect general ACPI video
+ * capabilities of present cards
+ */
+long acpi_is_video_device(acpi_handle handle)
+{
+	long video_caps = 0;
+
+	/* Is this device able to support video switching ? */
+	if (acpi_has_method(handle, "_DOD") || acpi_has_method(handle, "_DOS"))
+		video_caps |= ACPI_VIDEO_OUTPUT_SWITCHING;
+
+	/* Is this device able to retrieve a video ROM ? */
+	if (acpi_has_method(handle, "_ROM"))
+		video_caps |= ACPI_VIDEO_ROM_AVAILABLE;
+
+	/* Is this device able to configure which video head to be POSTed ? */
+	if (acpi_has_method(handle, "_VPO") &&
+	    acpi_has_method(handle, "_GPD") &&
+	    acpi_has_method(handle, "_SPD"))
+		video_caps |= ACPI_VIDEO_DEVICE_POSTING;
+
+	/* Only check for backlight functionality if one of the above hit. */
+	if (video_caps)
+		acpi_walk_namespace(ACPI_TYPE_DEVICE, handle,
+				    ACPI_UINT32_MAX, acpi_backlight_cap_match, NULL,
+				    &video_caps, NULL);
+
+	return video_caps;
+}
+EXPORT_SYMBOL(acpi_is_video_device);
+
 const char *acpi_device_hid(struct acpi_device *device)
 {
 	struct acpi_hardware_id *hid;
diff --git a/drivers/acpi/utils.c b/drivers/acpi/utils.c
index cd49a3982b6a..67c548ad3764 100644
--- a/drivers/acpi/utils.c
+++ b/drivers/acpi/utils.c
@@ -712,3 +712,18 @@ bool acpi_check_dsm(acpi_handle handle, const u8 *uuid, int rev, u64 funcs)
 	return false;
 }
 EXPORT_SYMBOL(acpi_check_dsm);
+
+/*
+ * acpi_backlight= handling, this is done here rather then in video_detect.c
+ * because __setup cannot be used in modules.
+ */
+char acpi_video_backlight_string[16];
+EXPORT_SYMBOL(acpi_video_backlight_string);
+
+static int __init acpi_backlight(char *str)
+{
+	strlcpy(acpi_video_backlight_string, str,
+		sizeof(acpi_video_backlight_string));
+	return 1;
+}
+__setup("acpi_backlight=", acpi_backlight);
diff --git a/drivers/acpi/video_detect.c b/drivers/acpi/video_detect.c
index c42feb2bacd0..815f75ef2411 100644
--- a/drivers/acpi/video_detect.c
+++ b/drivers/acpi/video_detect.c
@@ -1,106 +1,61 @@
 /*
+ *  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:
- * Provides acpi_is_video_device() for early scanning of ACPI devices in scan.c
- * There a Linux specific (Spec does not provide a HID for video devices) is
- * assigned
- *
  * 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
  *
- * Now acpi_video_get_capabilities() can be called to check which
- * capabilities the graphics cards plugged in support. The check for general
- * video capabilities will be triggered by the first caller of
- * acpi_video_get_capabilities(NULL); which will happen when the first
- * backlight switching supporting driver calls:
- * acpi_video_backlight_support();
- *
  * 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.
  *
- * If CONFIG_ACPI_VIDEO is neither set as "compiled in" (y) nor as a module (m)
- * this file will not be compiled, acpi_video_get_capabilities() and
- * acpi_video_backlight_support() will always return 0 and vendor specific
- * drivers always can handle backlight.
+ * 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 "internal.h"
+#include <linux/types.h>
+#include <acpi/video.h>
 
 ACPI_MODULE_NAME("video");
 #define _COMPONENT		ACPI_VIDEO_COMPONENT
 
-static long acpi_video_support;
-static bool acpi_video_caps_checked;
+void acpi_video_unregister_backlight(void);
 
-static acpi_status
-acpi_backlight_cap_match(acpi_handle handle, u32 level, void *context,
-			  void **return_value)
-{
-	long *cap = context;
+static bool backlight_notifier_registered;
+static struct notifier_block backlight_nb;
 
-	if (acpi_has_method(handle, "_BCM") &&
-	    acpi_has_method(handle, "_BCL")) {
-		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found generic backlight "
-				  "support\n"));
-		*cap |= ACPI_VIDEO_BACKLIGHT;
-		if (!acpi_has_method(handle, "_BQC"))
-			printk(KERN_WARNING FW_BUG PREFIX "No _BQC method, "
-				"cannot determine initial brightness\n");
-		/* We have backlight support, no need to scan further */
-		return AE_CTRL_TERMINATE;
-	}
-	return 0;
-}
+static enum acpi_backlight_type acpi_backlight_cmdline = acpi_backlight_undef;
+static enum acpi_backlight_type acpi_backlight_dmi = acpi_backlight_undef;
 
-/* Returns true if the ACPI object is a video device which can be
- * handled by video.ko.
- * The device will get a Linux specific CID added in scan.c to
- * identify the device as an ACPI graphics device
- * Be aware that the graphics device may not be physically present
- * Use acpi_video_get_capabilities() to detect general ACPI video
- * capabilities of present cards
- */
-long acpi_is_video_device(acpi_handle handle)
+static void acpi_video_parse_cmdline(void)
 {
-	long video_caps = 0;
-
-	/* Is this device able to support video switching ? */
-	if (acpi_has_method(handle, "_DOD") || acpi_has_method(handle, "_DOS"))
-		video_caps |= ACPI_VIDEO_OUTPUT_SWITCHING;
-
-	/* Is this device able to retrieve a video ROM ? */
-	if (acpi_has_method(handle, "_ROM"))
-		video_caps |= ACPI_VIDEO_ROM_AVAILABLE;
-
-	/* Is this device able to configure which video head to be POSTed ? */
-	if (acpi_has_method(handle, "_VPO") &&
-	    acpi_has_method(handle, "_GPD") &&
-	    acpi_has_method(handle, "_SPD"))
-		video_caps |= ACPI_VIDEO_DEVICE_POSTING;
-
-	/* Only check for backlight functionality if one of the above hit. */
-	if (video_caps)
-		acpi_walk_namespace(ACPI_TYPE_DEVICE, handle,
-				    ACPI_UINT32_MAX, acpi_backlight_cap_match, NULL,
-				    &video_caps, NULL);
-
-	return video_caps;
+	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;
 }
-EXPORT_SYMBOL(acpi_is_video_device);
 
 static acpi_status
 find_video(acpi_handle handle, u32 lvl, void *context, void **rv)
@@ -109,7 +64,7 @@ find_video(acpi_handle handle, u32 lvl, void *context, void **rv)
 	struct pci_dev *dev;
 	struct acpi_device *acpi_dev;
 
-	const struct acpi_device_id video_ids[] = {
+	static const struct acpi_device_id video_ids[] = {
 		{ACPI_VIDEO_HID, 0},
 		{"", 0},
 	};
@@ -130,11 +85,23 @@ find_video(acpi_handle handle, u32 lvl, void *context, void **rv)
  * buggy */
 static int video_detect_force_vendor(const struct dmi_system_id *d)
 {
-	acpi_video_support |= ACPI_VIDEO_BACKLIGHT_DMI_VENDOR;
+	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 struct dmi_system_id video_detect_dmi_table[] = {
+static int video_detect_force_native(const struct dmi_system_id *d)
+{
+	acpi_backlight_dmi = acpi_backlight_native;
+	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
@@ -174,137 +141,209 @@ static struct dmi_system_id video_detect_dmi_table[] = {
 		DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron 5737"),
 		},
 	},
+
+	/*
+	 * 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"),
+		},
+	},
+
+	/* 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=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=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"),
+		},
+	},
+
+	/* Non win8 machines which need native backlight nevertheless */
+	{
+	 /* 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_NAME, "102434U"),
+		},
+	},
+	{
+	 /* 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"),
+		},
+	},
 	{ },
 };
 
+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 &&
+	    acpi_video_get_backlight_type() != acpi_backlight_video)
+		acpi_video_unregister_backlight();
+
+	return NOTIFY_OK;
+}
+
 /*
- * Returns the video capabilities of a specific ACPI graphics device
+ * Determine which type of backlight interface to use on this system,
+ * First check cmdline, then dmi quirks, then do autodetect.
  *
- * if NULL is passed as argument all ACPI devices are enumerated and
- * all graphics capabilities of physically present devices are
- * summarized and returned. This is cached and done only once.
+ * 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.
  */
-long acpi_video_get_capabilities(acpi_handle graphics_handle)
+enum acpi_backlight_type acpi_video_get_backlight_type(void)
 {
-	long caps = 0;
-	struct acpi_device *tmp_dev;
-	acpi_status status;
-
-	if (acpi_video_caps_checked && graphics_handle == NULL)
-		return acpi_video_support;
-
-	if (!graphics_handle) {
-		/* Only do the global walk through all graphics devices once */
-		acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
-				    ACPI_UINT32_MAX, find_video, NULL,
-				    &caps, NULL);
-		/* There might be boot param flags set already... */
-		acpi_video_support |= caps;
-		acpi_video_caps_checked = 1;
-		/* Add blacklists here. Be careful to use the right *DMI* bits
-		 * to still be able to override logic via boot params, e.g.:
-		 *
-		 *   if (dmi_name_in_vendors("XY")) {
-		 *	acpi_video_support |=
-		 *		ACPI_VIDEO_BACKLIGHT_DMI_VENDOR;
-		 *}
-		 */
+	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);
-	} else {
-		status = acpi_bus_get_device(graphics_handle, &tmp_dev);
-		if (ACPI_FAILURE(status)) {
-			ACPI_EXCEPTION((AE_INFO, status, "Invalid device"));
-			return 0;
-		}
-		acpi_walk_namespace(ACPI_TYPE_DEVICE, graphics_handle,
+		acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
 				    ACPI_UINT32_MAX, find_video, NULL,
-				    &caps, NULL);
+				    &video_caps, NULL);
+		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;
 	}
-	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "We have 0x%lX video support %s %s\n",
-			  graphics_handle ? caps : acpi_video_support,
-			  graphics_handle ? "on device " : "in general",
-			  graphics_handle ? acpi_device_bid(tmp_dev) : ""));
-	return caps;
-}
-EXPORT_SYMBOL(acpi_video_get_capabilities);
+	mutex_unlock(&init_mutex);
 
-static void acpi_video_caps_check(void)
-{
-	/*
-	 * We must check whether the ACPI graphics device is physically plugged
-	 * in. Therefore this must be called after binding PCI and ACPI devices
-	 */
-	if (!acpi_video_caps_checked)
-		acpi_video_get_capabilities(NULL);
-}
+	if (acpi_backlight_cmdline != acpi_backlight_undef)
+		return acpi_backlight_cmdline;
 
-bool acpi_osi_is_win8(void)
-{
-	return acpi_gbl_osi_data >= ACPI_OSI_WIN_8;
-}
-EXPORT_SYMBOL(acpi_osi_is_win8);
+	if (acpi_backlight_dmi != acpi_backlight_undef)
+		return acpi_backlight_dmi;
 
-/* Promote the vendor interface instead of the generic video module.
- * This function allow DMI blacklists to be implemented by externals
- * platform drivers instead of putting a big blacklist in video_detect.c
- * After calling this function you will probably want to call
- * acpi_video_unregister() to make sure the video module is not loaded
- */
-void acpi_video_dmi_promote_vendor(void)
-{
-	acpi_video_caps_check();
-	acpi_video_support |= ACPI_VIDEO_BACKLIGHT_DMI_VENDOR;
-}
-EXPORT_SYMBOL(acpi_video_dmi_promote_vendor);
-
-/* To be called when a driver who previously promoted the vendor
- * interface */
-void acpi_video_dmi_demote_vendor(void)
-{
-	acpi_video_caps_check();
-	acpi_video_support &= ~ACPI_VIDEO_BACKLIGHT_DMI_VENDOR;
-}
-EXPORT_SYMBOL(acpi_video_dmi_demote_vendor);
-
-/* Returns true if video.ko can do backlight switching */
-int acpi_video_backlight_support(void)
-{
-	acpi_video_caps_check();
-
-	/* First check for boot param -> highest prio */
-	if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_FORCE_VENDOR)
-		return 0;
-	else if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_FORCE_VIDEO)
-		return 1;
+	if (!(video_caps & ACPI_VIDEO_BACKLIGHT))
+		return acpi_backlight_vendor;
 
-	/* Then check for DMI blacklist -> second highest prio */
-	if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_DMI_VENDOR)
-		return 0;
-	else if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_DMI_VIDEO)
-		return 1;
+	if (acpi_osi_is_win8() && backlight_device_registered(BACKLIGHT_RAW))
+		return acpi_backlight_native;
 
-	/* Then go the default way */
-	return acpi_video_support & ACPI_VIDEO_BACKLIGHT;
+	return acpi_backlight_video;
 }
-EXPORT_SYMBOL(acpi_video_backlight_support);
+EXPORT_SYMBOL(acpi_video_get_backlight_type);
 
 /*
- * Use acpi_backlight=vendor/video to force that backlight switching
- * is processed by vendor specific acpi drivers or video.ko driver.
+ * 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
  */
-static int __init acpi_backlight(char *str)
+void acpi_video_set_dmi_backlight_type(enum acpi_backlight_type type)
 {
-	if (str == NULL || *str == '\0')
-		return 1;
-	else {
-		if (!strcmp("vendor", str))
-			acpi_video_support |=
-				ACPI_VIDEO_BACKLIGHT_FORCE_VENDOR;
-		if (!strcmp("video", str))
-			acpi_video_support |=
-				ACPI_VIDEO_BACKLIGHT_FORCE_VIDEO;
-	}
-	return 1;
+	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);
 }
-__setup("acpi_backlight=", acpi_backlight);