[PATCH] [ACPI] Default to using the native backlight control on Windows 8 systems

[Matthew Garrett]

The list of machines in the "Use native backlight" table is getting longer
and longer, which is a solid indication that we're doing something wrong.
Disable the ACPI backlight interface if the system claims to be Windows 8
or later.

Signed-off-by: Matthew Garrett <matthew.garrett at nebula.com>
---

Let's at least get this into -next for 3.16 and figure out whether the
drivers actually work now.

 drivers/acpi/video.c | 139 +--------------------------------------------------
 1 file changed, 1 insertion(+), 138 deletions(-)

diff --git a/drivers/acpi/video.c b/drivers/acpi/video.c
index 48c7e8a..21d2fc9 100644
--- a/drivers/acpi/video.c
+++ b/drivers/acpi/video.c
@@ -78,14 +78,6 @@ 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.
- */
-static int use_native_backlight_param = -1;
-module_param_named(use_native_backlight, use_native_backlight_param, int, 0444);
-static bool use_native_backlight_dmi = false;
-
 static int register_count;
 static struct mutex video_list_lock;
 static struct list_head video_bus_head;
@@ -230,18 +222,9 @@ static int acpi_video_get_next_level(struct acpi_video_device *device,
 static int acpi_video_switch_brightness(struct acpi_video_device *device,
 					 int event);
 
-static bool acpi_video_use_native_backlight(void)
-{
-	if (use_native_backlight_param != -1)
-		return use_native_backlight_param;
-	else
-		return use_native_backlight_dmi;
-}
-
 static bool acpi_video_verify_backlight_support(void)
 {
-	if (acpi_osi_is_win8() && acpi_video_use_native_backlight() &&
-	    backlight_device_registered(BACKLIGHT_RAW))
+	if (acpi_osi_is_win8() && backlight_device_registered(BACKLIGHT_RAW))
 		return false;
 	return acpi_video_backlight_support();
 }
@@ -405,12 +388,6 @@ static int __init video_set_bqc_offset(const struct dmi_system_id *d)
 	return 0;
 }
 
-static int __init video_set_use_native_backlight(const struct dmi_system_id *d)
-{
-	use_native_backlight_dmi = true;
-	return 0;
-}
-
 static struct dmi_system_id video_dmi_table[] __initdata = {
 	/*
 	 * Broken _BQC workaround http://bugzilla.kernel.org/show_bug.cgi?id=13121
@@ -455,120 +432,6 @@ static struct dmi_system_id video_dmi_table[] __initdata = {
 		DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 7720"),
 		},
 	},
-	{
-	 .callback = video_set_use_native_backlight,
-	 .ident = "ThinkPad T430s",
-	 .matches = {
-		DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
-		DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad T430s"),
-		},
-	},
-	{
-	 .callback = video_set_use_native_backlight,
-	 .ident = "ThinkPad X230",
-	 .matches = {
-		DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
-		DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad X230"),
-		},
-	},
-	{
-	.callback = video_set_use_native_backlight,
-	.ident = "ThinkPad X1 Carbon",
-	.matches = {
-		DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
-		DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad X1 Carbon"),
-		},
-	},
-	{
-	 .callback = video_set_use_native_backlight,
-	 .ident = "Lenovo Yoga 13",
-	 .matches = {
-		DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
-		DMI_MATCH(DMI_PRODUCT_VERSION, "Lenovo IdeaPad Yoga 13"),
-		},
-	},
-	{
-	 .callback = video_set_use_native_backlight,
-	 .ident = "Dell Inspiron 7520",
-	 .matches = {
-		DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
-		DMI_MATCH(DMI_PRODUCT_VERSION, "Inspiron 7520"),
-		},
-	},
-	{
-	 .callback = video_set_use_native_backlight,
-	 .ident = "Acer Aspire 5733Z",
-	 .matches = {
-		DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
-		DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5733Z"),
-		},
-	},
-	{
-	 .callback = video_set_use_native_backlight,
-	 .ident = "Acer Aspire V5-431",
-	 .matches = {
-		DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
-		DMI_MATCH(DMI_PRODUCT_NAME, "Aspire V5-431"),
-		},
-	},
-	{
-	.callback = video_set_use_native_backlight,
-	.ident = "HP ProBook 4340s",
-	.matches = {
-		DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
-		DMI_MATCH(DMI_PRODUCT_VERSION, "HP ProBook 4340s"),
-		},
-	},
-	{
-	.callback = video_set_use_native_backlight,
-	.ident = "HP ProBook 2013 models",
-	.matches = {
-		DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
-		DMI_MATCH(DMI_PRODUCT_NAME, "HP ProBook "),
-		DMI_MATCH(DMI_PRODUCT_NAME, " G1"),
-		},
-	},
-	{
-	.callback = video_set_use_native_backlight,
-	.ident = "HP EliteBook 2013 models",
-	.matches = {
-		DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
-		DMI_MATCH(DMI_PRODUCT_NAME, "HP EliteBook "),
-		DMI_MATCH(DMI_PRODUCT_NAME, " G1"),
-		},
-	},
-	{
-	.callback = video_set_use_native_backlight,
-	.ident = "HP ZBook 14",
-	.matches = {
-		DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
-		DMI_MATCH(DMI_PRODUCT_NAME, "HP ZBook 14"),
-		},
-	},
-	{
-	.callback = video_set_use_native_backlight,
-	.ident = "HP ZBook 15",
-	.matches = {
-		DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
-		DMI_MATCH(DMI_PRODUCT_NAME, "HP ZBook 15"),
-		},
-	},
-	{
-	.callback = video_set_use_native_backlight,
-	.ident = "HP ZBook 17",
-	.matches = {
-		DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
-		DMI_MATCH(DMI_PRODUCT_NAME, "HP ZBook 17"),
-		},
-	},
-	{
-	.callback = video_set_use_native_backlight,
-	.ident = "HP EliteBook 8780w",
-	.matches = {
-		DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
-		DMI_MATCH(DMI_PRODUCT_NAME, "HP EliteBook 8780w"),
-		},
-	},
 	{}
 };
 
-- 
1.9.0