From fbc9fe1b4f222a7c575e3bd8e9defe59c6190a04 Mon Sep 17 00:00:00 2001 From: Aaron Lu Date: Fri, 11 Oct 2013 21:27:45 +0800 Subject: ACPI / video: Do not register backlight if win8 and native interface exists According to Matthew Garrett, "Windows 8 leaves backlight control up to individual graphics drivers rather than making ACPI calls itself. There's plenty of evidence to suggest that the Intel driver for Windows [8] doesn't use the ACPI interface, including the fact that it's broken on a bunch of machines when the OS claims to support Windows 8. The simplest thing to do appears to be to disable the ACPI backlight interface on these systems". So for Win8 systems, if there is native backlight control interface registered by GPU driver, ACPI video does not need to register its own. Since there are systems that don't work well with this approach, a parameter for video module named use_native_backlight is introduced and has the value of false by default. For users who have a broken ACPI video backlight interface, video.use_native_backlight=1 is needed in kernel cmdline. Signed-off-by: Aaron Lu Signed-off-by: Rafael J. Wysocki --- drivers/acpi/video_detect.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'drivers/acpi/video_detect.c') diff --git a/drivers/acpi/video_detect.c b/drivers/acpi/video_detect.c index 940edbf2fe8f..b6399343de51 100644 --- a/drivers/acpi/video_detect.c +++ b/drivers/acpi/video_detect.c @@ -233,11 +233,11 @@ static void acpi_video_caps_check(void) acpi_video_get_capabilities(NULL); } -bool acpi_video_backlight_quirks(void) +bool acpi_osi_is_win8(void) { return acpi_gbl_osi_data >= ACPI_OSI_WIN_8; } -EXPORT_SYMBOL(acpi_video_backlight_quirks); +EXPORT_SYMBOL(acpi_osi_is_win8); /* Promote the vendor interface instead of the generic video module. * This function allow DMI blacklists to be implemented by externals -- cgit v1.2.3-70-g09d2 From a8d52f4495f21da3f47f7318301abf6823ec6648 Mon Sep 17 00:00:00 2001 From: Lennart Poettering Date: Mon, 14 Oct 2013 02:55:05 +0200 Subject: ACPI / video: Add Lenovo IdeaPad Yoga 13 to acpi video detect blacklist On the Yoga 13 the backlight control doesn't work via ACPI. (And doesn't work either with the low-level platform driver ideapad_laptop; but works correctly via the intel video driver). This patch hence adds the Yoga 13 to the ACPI video detect blacklist, to make sure the broken ACPI backlight device is never exposed to userspace. Note that this appears unrelated to the Windows 8 backlight issues tracked here: https://bugzilla.kernel.org/show_bug.cgi?id=51231 https://bugzilla.kernel.org/show_bug.cgi?id=60682 The Yoga's ACPI backlight controls work neither with nor without acpi_osi="!Windows 2012" on the kernel command line. It appears that backlight control via the EC simply is not available at all, regardless whether done via ACPI or via the vendor driver. Signed-off-by: Lennart Poettering Signed-off-by: Rafael J. Wysocki --- drivers/acpi/video_detect.c | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'drivers/acpi/video_detect.c') diff --git a/drivers/acpi/video_detect.c b/drivers/acpi/video_detect.c index b6399343de51..84875fd4c74f 100644 --- a/drivers/acpi/video_detect.c +++ b/drivers/acpi/video_detect.c @@ -168,6 +168,14 @@ static struct dmi_system_id video_detect_dmi_table[] = { DMI_MATCH(DMI_PRODUCT_NAME, "UL30A"), }, }, + { + .callback = video_detect_force_vendor, + .ident = "Lenovo Yoga 13", + .matches = { + DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"), + DMI_MATCH(DMI_PRODUCT_VERSION, "Lenovo IdeaPad Yoga 13"), + }, + }, { }, }; -- cgit v1.2.3-70-g09d2