From mboxrd@z Thu Jan 1 00:00:00 1970 From: Aaron Lu Subject: Re: [PATCH v4 3/4] ACPI / video: Do not register backlight if win8 and native interface exists Date: Thu, 10 Oct 2013 09:02:55 +0800 Message-ID: <5255FCBF.6090708@intel.com> References: <1381214401-24672-1-git-send-email-aaron.lu@intel.com> <1381214401-24672-4-git-send-email-aaron.lu@intel.com> <9897358.0Z0t2PgJOe@vostro.rjw.lan> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <9897358.0Z0t2PgJOe@vostro.rjw.lan> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: intel-gfx-bounces+gcfxdi-intel-gfx=m.gmane.org@lists.freedesktop.org Errors-To: intel-gfx-bounces+gcfxdi-intel-gfx=m.gmane.org@lists.freedesktop.org To: "Rafael J. Wysocki" Cc: James Hogan , Martin Steigerwald , Felipe Contreras , dri-devel@lists.freedesktop.org, platform-driver-x86@vger.kernel.org, Henrique de Moraes Holschuh , Matthew Garrett , linux-acpi@vger.kernel.org, Kalle Valo , Yves-Alexis Perez , Mike Galbraith , Lee Chun-Yi , Ben Jencks , =?UTF-8?B?SsO2cmcgT3R0ZQ==?= , intel-gfx@lists.freedesktop.org, Joerg Platte , Seth Forshee , Igor Gnatenko , Mika Westerberg , linux-kernel@vger.kernel.org, Richard Purdie List-Id: linux-acpi@vger.kernel.org On 10/10/2013 08:29 AM, Rafael J. Wysocki wrote: > On Tuesday, October 08, 2013 02:40:00 PM Aaron Lu wrote: >> 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 will not register its own. For >> users who prefer to keep ACPI video's backlight interface, the existing >> kernel cmdline option acpi_backlight=video can be used. >> >> Signed-off-by: Aaron Lu >> Tested-by: Igor Gnatenko >> Tested-by: Yves-Alexis Perez >> Tested-by: Mika Westerberg >> --- >> drivers/acpi/internal.h | 5 ++--- >> drivers/acpi/video.c | 10 +++++----- >> drivers/acpi/video_detect.c | 14 ++++++++++++-- >> 3 files changed, 19 insertions(+), 10 deletions(-) >> >> diff --git a/drivers/acpi/internal.h b/drivers/acpi/internal.h >> index 20f4233..453ae8d 100644 >> --- a/drivers/acpi/internal.h >> +++ b/drivers/acpi/internal.h >> @@ -169,9 +169,8 @@ int acpi_create_platform_device(struct acpi_device *adev, >> Video >> -------------------------------------------------------------------------- */ >> #if defined(CONFIG_ACPI_VIDEO) || defined(CONFIG_ACPI_VIDEO_MODULE) >> -bool acpi_video_backlight_quirks(void); >> -#else >> -static inline bool acpi_video_backlight_quirks(void) { return false; } >> +bool acpi_osi_is_win8(void); >> +bool acpi_video_verify_backlight_support(void); >> #endif >> >> #endif /* _ACPI_INTERNAL_H_ */ >> diff --git a/drivers/acpi/video.c b/drivers/acpi/video.c >> index 3bd1eaa..343db59 100644 >> --- a/drivers/acpi/video.c >> +++ b/drivers/acpi/video.c >> @@ -1256,8 +1256,8 @@ acpi_video_switch_brightness(struct acpi_video_device *device, int event) >> unsigned long long level_current, level_next; >> int result = -EINVAL; >> >> - /* no warning message if acpi_backlight=vendor is used */ >> - if (!acpi_video_backlight_support()) >> + /* no warning message if acpi_backlight=vendor or a quirk is used */ >> + if (!acpi_video_verify_backlight_support()) >> return 0; >> >> if (!device->brightness) >> @@ -1386,13 +1386,13 @@ acpi_video_bus_get_devices(struct acpi_video_bus *video, >> static int acpi_video_bus_start_devices(struct acpi_video_bus *video) >> { >> return acpi_video_bus_DOS(video, 0, >> - acpi_video_backlight_quirks() ? 1 : 0); >> + acpi_osi_is_win8() ? 1 : 0); >> } >> >> static int acpi_video_bus_stop_devices(struct acpi_video_bus *video) >> { >> return acpi_video_bus_DOS(video, 0, >> - acpi_video_backlight_quirks() ? 0 : 1); >> + acpi_osi_is_win8() ? 0 : 1); >> } >> >> static void acpi_video_bus_notify(struct acpi_device *device, u32 event) >> @@ -1558,7 +1558,7 @@ acpi_video_bus_match(acpi_handle handle, u32 level, void *context, >> >> static void acpi_video_dev_register_backlight(struct acpi_video_device *device) >> { >> - if (acpi_video_backlight_support()) { >> + if (acpi_video_verify_backlight_support()) { >> struct backlight_properties props; >> struct pci_dev *pdev; >> acpi_handle acpi_parent; >> diff --git a/drivers/acpi/video_detect.c b/drivers/acpi/video_detect.c >> index 940edbf..23d7d26 100644 >> --- a/drivers/acpi/video_detect.c >> +++ b/drivers/acpi/video_detect.c >> @@ -37,6 +37,7 @@ >> #include >> #include >> #include >> +#include >> >> #include "internal.h" >> >> @@ -233,11 +234,11 @@ 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 >> @@ -283,6 +284,15 @@ int acpi_video_backlight_support(void) >> } >> EXPORT_SYMBOL(acpi_video_backlight_support); >> >> +bool acpi_video_verify_backlight_support(void) >> +{ >> + if (!(acpi_video_support & ACPI_VIDEO_BACKLIGHT_FORCE_VIDEO) && >> + acpi_osi_is_win8() && backlight_device_registered(BACKLIGHT_RAW)) >> + return false; > > If I'm not mistaken, this will introduce a regression for the people who have > problems with the native i915 backlight on Win8-compatible systems. I'd prefer > to avoid that at this point. > OK, I see. Then I'm afraid a new kernel command line option is needed, something like video.use_native_backlight and set it to false by default, then for people who need to avoid the ACPI video backlight interface, they can add video.use_native_backlight=true to kernel cmdline. One thing I need to mention is, with the new cmdline option, users will need to manually add a kernel cmdline option to make backlight work on their systems, while they can already make backlight work by modifying xorg.conf to specify using intel_backlight interface, so it doesn't seem this patchset will be very useful then... Thanks, Aaron >> + return acpi_video_backlight_support(); >> +} >> +EXPORT_SYMBOL(acpi_video_verify_backlight_support); >> + >> /* >> * Use acpi_backlight=vendor/video to force that backlight switching >> * is processed by vendor specific acpi drivers or video.ko driver. > > Thanks! >