subject:"\[PATCH v4 3\/4\] ACPI \/ video\: Do not register backlight if win8 and native interface exists"

Re: [PATCH v4 3/4] ACPI / video: Do not register backlight if win8 and native interface exists

2013-10-10 Thread Aaron Lu

On 10/10/2013 08:59 PM, Rafael J. Wysocki wrote:
> On Thursday, October 10, 2013 09:02:55 AM Aaron Lu wrote:
>> 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

Re: [PATCH v4 3/4] ACPI / video: Do not register backlight if win8 and native interface exists

2013-10-10 Thread Rafael J. Wysocki

On Thursday, October 10, 2013 09:02:55 AM Aaron Lu wrote:
> 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) &&
> >>

Re: [PATCH v4 3/4] ACPI / video: Do not register backlight if win8 and native interface exists

2013-10-10 Thread Rafael J. Wysocki

On Thursday, October 10, 2013 09:02:55 AM Aaron Lu wrote:
 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 aaron...@intel.com
  Tested-by: Igor Gnatenko i.gnatenko.br...@gmail.com
  Tested-by: Yves-Alexis Perez cor...@debian.org
  Tested-by: Mika Westerberg mika.westerb...@linux.intel.com
  ---
   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 linux/acpi.h
   #include linux/dmi.h
   #include linux/pci.h
  +#include linux/backlight.h
   
   #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

Re: [PATCH v4 3/4] ACPI / video: Do not register backlight if win8 and native interface exists

2013-10-10 Thread Aaron Lu

On 10/10/2013 08:59 PM, Rafael J. Wysocki wrote:
 On Thursday, October 10, 2013 09:02:55 AM Aaron Lu wrote:
 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 aaron...@intel.com
 Tested-by: Igor Gnatenko i.gnatenko.br...@gmail.com
 Tested-by: Yves-Alexis Perez cor...@debian.org
 Tested-by: Mika Westerberg mika.westerb...@linux.intel.com
 ---
  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 linux/acpi.h
  #include linux/dmi.h
  #include linux/pci.h
 +#include linux/backlight.h
  
  #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

Re: [PATCH v4 3/4] ACPI / video: Do not register backlight if win8 and native interface exists

2013-10-09 Thread Aaron Lu

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

Re: [PATCH v4 3/4] ACPI / video: Do not register backlight if win8 and native interface exists

2013-10-09 Thread Rafael J. Wysocki

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.

> + return acpi_video_backlight_support();
> +}
> +EXPORT_SYMBOL(acpi_video_verify_backlight_support);
> +
>

Re: [PATCH v4 3/4] ACPI / video: Do not register backlight if win8 and native interface exists

2013-10-09 Thread Rafael J. Wysocki

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 aaron...@intel.com
 Tested-by: Igor Gnatenko i.gnatenko.br...@gmail.com
 Tested-by: Yves-Alexis Perez cor...@debian.org
 Tested-by: Mika Westerberg mika.westerb...@linux.intel.com
 ---
  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 linux/acpi.h
  #include linux/dmi.h
  #include linux/pci.h
 +#include linux/backlight.h
  
  #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.

 + return acpi_video_backlight_support();
 +}

Re: [PATCH v4 3/4] ACPI / video: Do not register backlight if win8 and native interface exists

2013-10-09 Thread Aaron Lu

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 aaron...@intel.com
 Tested-by: Igor Gnatenko i.gnatenko.br...@gmail.com
 Tested-by: Yves-Alexis Perez cor...@debian.org
 Tested-by: Mika Westerberg mika.westerb...@linux.intel.com
 ---
  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 linux/acpi.h
  #include linux/dmi.h
  #include linux/pci.h
 +#include linux/backlight.h
  
  #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

[PATCH v4 3/4] ACPI / video: Do not register backlight if win8 and native interface exists

2013-10-08 Thread Aaron Lu

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;
+   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.
-- 
1.8.4.12.g2ea3df6

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[PATCH v4 3/4] ACPI / video: Do not register backlight if win8 and native interface exists

2013-10-08 Thread Aaron Lu

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 aaron...@intel.com
Tested-by: Igor Gnatenko i.gnatenko.br...@gmail.com
Tested-by: Yves-Alexis Perez cor...@debian.org
Tested-by: Mika Westerberg mika.westerb...@linux.intel.com
---
 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 linux/acpi.h
 #include linux/dmi.h
 #include linux/pci.h
+#include linux/backlight.h
 
 #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;
+   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.
-- 
1.8.4.12.g2ea3df6

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Re: [PATCH v4 3/4] ACPI / video: Do not register backlight if win8 and native interface exists

Re: [PATCH v4 3/4] ACPI / video: Do not register backlight if win8 and native interface exists

Re: [PATCH v4 3/4] ACPI / video: Do not register backlight if win8 and native interface exists

Re: [PATCH v4 3/4] ACPI / video: Do not register backlight if win8 and native interface exists

Re: [PATCH v4 3/4] ACPI / video: Do not register backlight if win8 and native interface exists

Re: [PATCH v4 3/4] ACPI / video: Do not register backlight if win8 and native interface exists

[PATCH v4 3/4] ACPI / video: Do not register backlight if win8 and native interface exists

[PATCH v4 3/4] ACPI / video: Do not register backlight if win8 and native interface exists

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