[Regression]: Changing brightness does not work with v3.16-rc4

[Regression]: Changing brightness does not work with v3.16-rc4

[Julian Wollrath]

Hi,

changing the brightness on my Thinkpad X230 with Intel HD4000 graphics,
stopped working after commit 886129a8eebe (ACPI / video: change
acpi-video brightness_switch_enabled default to 0). Changing it back to
1, fixes the problem, if "acpi_osi=!Windows 2012" is also set. Before
that commit just setting "acpi_osi=!Windows 2012" was enough to get
changing the brightness working.


With best regards,
Julian Wollrath

Re: [Regression]: Changing brightness does not work with v3.16-rc4

[Julian Wollrath]

Hi,

> changing the brightness on my Thinkpad X230 with Intel HD4000
> graphics, stopped working after commit 886129a8eebe (ACPI / video:
> change acpi-video brightness_switch_enabled default to 0). Changing
> it back to 1, fixes the problem, if "acpi_osi=!Windows 2012" is also
> set. Before that commit just setting "acpi_osi=!Windows 2012" was
> enough to get changing the brightness working.
small correction: It setting "acpi_osi=!Windows 2012" does only help
when using a kernel with commit 886129a8eebe as HEAD, with v3.16-rc4
setting video.brightness_switch_enabled=1 and acpi_osi=!Windows 2012 or
just one of them, does not make changing the brightness work again.
> 
> 
> With best regards,
> Julian Wollrath

Re: [Regression]: Changing brightness does not work with v3.16-rc4

[Aaron Lu]

On 07/13/2014 12:06 AM, Julian Wollrath wrote:
> Hi,
> 
> changing the brightness on my Thinkpad X230 with Intel HD4000 graphics,
> stopped working after commit 886129a8eebe (ACPI / video: change
> acpi-video brightness_switch_enabled default to 0). Changing it back to
> 1, fixes the problem, if "acpi_osi=!Windows 2012" is also set. Before
> that commit just setting "acpi_osi=!Windows 2012" was enough to get
> changing the brightness working.

Does your system have /sys/class/backlight/intel_backlight? Does it work
if you manually change the brightness file like this:
# cd /sys/class/backlight/intel_backlight
# cat max_brightness
xxxxx
# echo xxx > brightness
# echo xxx > brightness
...

Thanks,
Aaron

> 
> 
> With best regards,
> Julian Wollrath
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> 

Re: [Regression]: Changing brightness does not work with v3.16-rc4

[Julian Wollrath]

Hi,

Am Mon, 14 Jul 2014 10:06:21 +0800
schrieb Aaron Lu <aaron.lu@intel.com>:
> > changing the brightness on my Thinkpad X230 with Intel HD4000
> > graphics, stopped working after commit 886129a8eebe (ACPI / video:
> > change acpi-video brightness_switch_enabled default to 0). Changing
> > it back to 1, fixes the problem, if "acpi_osi=!Windows 2012" is
> > also set. Before that commit just setting "acpi_osi=!Windows 2012"
> > was enough to get changing the brightness working.
> 
> Does your system have /sys/class/backlight/intel_backlight? Does it
> work if you manually change the brightness file like this:
> # cd /sys/class/backlight/intel_backlight
> # cat max_brightness
> xxxxx
> # echo xxx > brightness
> # echo xxx > brightness
> ...
yes, my system has /sys/class/backlight/intel_backlight and changing
the brightness works with writing to the "brightness"-file.

Cheers,
Julian

Re: [Regression]: Changing brightness does not work with v3.16-rc4

[Rafael J. Wysocki]

On Saturday, July 12, 2014 06:24:52 PM Julian Wollrath wrote:
> Hi,
> 
> > changing the brightness on my Thinkpad X230 with Intel HD4000
> > graphics, stopped working after commit 886129a8eebe (ACPI / video:
> > change acpi-video brightness_switch_enabled default to 0). Changing
> > it back to 1, fixes the problem, if "acpi_osi=!Windows 2012" is also
> > set. Before that commit just setting "acpi_osi=!Windows 2012" was
> > enough to get changing the brightness working.
>
> small correction: It setting "acpi_osi=!Windows 2012" does only help
> when using a kernel with commit 886129a8eebe as HEAD, with v3.16-rc4
> setting video.brightness_switch_enabled=1 and acpi_osi=!Windows 2012 or
> just one of them, does not make changing the brightness work again.

And reverting commit 751109aad583 (ACPI / video: Change the default for
video.use_native_backlight to 1) make that last problem go away, right?

We are going to rever commit 886129a8eebe for other reasons, so can you
please revert it from 3.16-rc5 on your system and report back?

Rafael

Re: [Regression]: Changing brightness does not work with v3.16-rc4

[Julian Wollrath]

Am Mon, 14 Jul 2014 20:21:19 +0200
schrieb "Rafael J. Wysocki" <rjw@rjwysocki.net>:

> On Saturday, July 12, 2014 06:24:52 PM Julian Wollrath wrote:
> > Hi,
> > 
> > > changing the brightness on my Thinkpad X230 with Intel HD4000
> > > graphics, stopped working after commit 886129a8eebe (ACPI / video:
> > > change acpi-video brightness_switch_enabled default to 0).
> > > Changing it back to 1, fixes the problem, if "acpi_osi=!Windows
> > > 2012" is also set. Before that commit just setting
> > > "acpi_osi=!Windows 2012" was enough to get changing the
> > > brightness working.
> >
> > small correction: It setting "acpi_osi=!Windows 2012" does only help
> > when using a kernel with commit 886129a8eebe as HEAD, with v3.16-rc4
> > setting video.brightness_switch_enabled=1 and acpi_osi=!Windows
> > 2012 or just one of them, does not make changing the brightness
> > work again.
> 
> And reverting commit 751109aad583 (ACPI / video: Change the default
> for video.use_native_backlight to 1) make that last problem go away,
> right?
> 
> We are going to rever commit 886129a8eebe for other reasons, so can
> you please revert it from 3.16-rc5 on your system and report back?
Yes, with both 751109aad583 and 886129a8eebe reverted, changing the
brightness works again.

Cheers,
Julian

> 
> Rafael
> 

Re: [Regression]: Changing brightness does not work with v3.16-rc4

[Julian Wollrath]

Am Mon, 14 Jul 2014 21:10:47 +0200
schrieb "Rafael J. Wysocki" <rjw@rjwysocki.net>:

> On Monday, July 14, 2014 09:02:34 PM Rafael J. Wysocki wrote:
> > On Monday, July 14, 2014 08:34:22 PM Julian Wollrath wrote:
> > > Am Mon, 14 Jul 2014 20:21:19 +0200
> > > schrieb "Rafael J. Wysocki" <rjw@rjwysocki.net>:
> > > 
> > > > On Saturday, July 12, 2014 06:24:52 PM Julian Wollrath wrote:
> > > > > Hi,
> > > > > 
> > > > > > changing the brightness on my Thinkpad X230 with Intel
> > > > > > HD4000 graphics, stopped working after commit 886129a8eebe
> > > > > > (ACPI / video: change acpi-video brightness_switch_enabled
> > > > > > default to 0). Changing it back to 1, fixes the problem, if
> > > > > > "acpi_osi=!Windows 2012" is also set. Before that commit
> > > > > > just setting "acpi_osi=!Windows 2012" was enough to get
> > > > > > changing the brightness working.
> > > > >
> > > > > small correction: It setting "acpi_osi=!Windows 2012" does
> > > > > only help when using a kernel with commit 886129a8eebe as
> > > > > HEAD, with v3.16-rc4 setting
> > > > > video.brightness_switch_enabled=1 and acpi_osi=!Windows 2012
> > > > > or just one of them, does not make changing the brightness
> > > > > work again.
> > > > 
> > > > And reverting commit 751109aad583 (ACPI / video: Change the
> > > > default for video.use_native_backlight to 1) make that last
> > > > problem go away, right?
> > > > 
> > > > We are going to rever commit 886129a8eebe for other reasons, so
> > > > can you please revert it from 3.16-rc5 on your system and
> > > > report back?
> > > Yes, with both 751109aad583 and 886129a8eebe reverted, changing
> > > the brightness works again.
> > 
> > What if you revert 886129a8eebe alone?
> 
> I mean, what exactly do you need to pass to the kernel command line
> in that case to make brightness switching work?
I need to pass
  acpi_osi="!Windows 2012" video.brightness_switch_enabled=1 video.use_native_backlight=-1

If I leave one of these parameters out, the brightness switch stops
working.

Cheers,
Julian

Re: [Regression]: Changing brightness does not work with v3.16-rc4

[Rafael J. Wysocki]

On Monday, July 14, 2014 08:34:22 PM Julian Wollrath wrote:
> Am Mon, 14 Jul 2014 20:21:19 +0200
> schrieb "Rafael J. Wysocki" <rjw@rjwysocki.net>:
> 
> > On Saturday, July 12, 2014 06:24:52 PM Julian Wollrath wrote:
> > > Hi,
> > > 
> > > > changing the brightness on my Thinkpad X230 with Intel HD4000
> > > > graphics, stopped working after commit 886129a8eebe (ACPI / video:
> > > > change acpi-video brightness_switch_enabled default to 0).
> > > > Changing it back to 1, fixes the problem, if "acpi_osi=!Windows
> > > > 2012" is also set. Before that commit just setting
> > > > "acpi_osi=!Windows 2012" was enough to get changing the
> > > > brightness working.
> > >
> > > small correction: It setting "acpi_osi=!Windows 2012" does only help
> > > when using a kernel with commit 886129a8eebe as HEAD, with v3.16-rc4
> > > setting video.brightness_switch_enabled=1 and acpi_osi=!Windows
> > > 2012 or just one of them, does not make changing the brightness
> > > work again.
> > 
> > And reverting commit 751109aad583 (ACPI / video: Change the default
> > for video.use_native_backlight to 1) make that last problem go away,
> > right?
> > 
> > We are going to rever commit 886129a8eebe for other reasons, so can
> > you please revert it from 3.16-rc5 on your system and report back?
> Yes, with both 751109aad583 and 886129a8eebe reverted, changing the
> brightness works again.

What if you revert 886129a8eebe alone?

Rafael

Re: [Regression]: Changing brightness does not work with v3.16-rc4

[Rafael J. Wysocki]

On Monday, July 14, 2014 09:02:34 PM Rafael J. Wysocki wrote:
> On Monday, July 14, 2014 08:34:22 PM Julian Wollrath wrote:
> > Am Mon, 14 Jul 2014 20:21:19 +0200
> > schrieb "Rafael J. Wysocki" <rjw@rjwysocki.net>:
> > 
> > > On Saturday, July 12, 2014 06:24:52 PM Julian Wollrath wrote:
> > > > Hi,
> > > > 
> > > > > changing the brightness on my Thinkpad X230 with Intel HD4000
> > > > > graphics, stopped working after commit 886129a8eebe (ACPI / video:
> > > > > change acpi-video brightness_switch_enabled default to 0).
> > > > > Changing it back to 1, fixes the problem, if "acpi_osi=!Windows
> > > > > 2012" is also set. Before that commit just setting
> > > > > "acpi_osi=!Windows 2012" was enough to get changing the
> > > > > brightness working.
> > > >
> > > > small correction: It setting "acpi_osi=!Windows 2012" does only help
> > > > when using a kernel with commit 886129a8eebe as HEAD, with v3.16-rc4
> > > > setting video.brightness_switch_enabled=1 and acpi_osi=!Windows
> > > > 2012 or just one of them, does not make changing the brightness
> > > > work again.
> > > 
> > > And reverting commit 751109aad583 (ACPI / video: Change the default
> > > for video.use_native_backlight to 1) make that last problem go away,
> > > right?
> > > 
> > > We are going to rever commit 886129a8eebe for other reasons, so can
> > > you please revert it from 3.16-rc5 on your system and report back?
> > Yes, with both 751109aad583 and 886129a8eebe reverted, changing the
> > brightness works again.
> 
> What if you revert 886129a8eebe alone?

I mean, what exactly do you need to pass to the kernel command line in that
case to make brightness switching work?

Rafael

Re: [Regression]: Changing brightness does not work with v3.16-rc4

[Rafael J. Wysocki]

On Monday, July 14, 2014 08:56:29 PM Julian Wollrath wrote:
> Am Mon, 14 Jul 2014 21:10:47 +0200
> schrieb "Rafael J. Wysocki" <rjw@rjwysocki.net>:
> 
> > On Monday, July 14, 2014 09:02:34 PM Rafael J. Wysocki wrote:
> > > On Monday, July 14, 2014 08:34:22 PM Julian Wollrath wrote:
> > > > Am Mon, 14 Jul 2014 20:21:19 +0200
> > > > schrieb "Rafael J. Wysocki" <rjw@rjwysocki.net>:
> > > > 
> > > > > On Saturday, July 12, 2014 06:24:52 PM Julian Wollrath wrote:
> > > > > > Hi,
> > > > > > 
> > > > > > > changing the brightness on my Thinkpad X230 with Intel
> > > > > > > HD4000 graphics, stopped working after commit 886129a8eebe
> > > > > > > (ACPI / video: change acpi-video brightness_switch_enabled
> > > > > > > default to 0). Changing it back to 1, fixes the problem, if
> > > > > > > "acpi_osi=!Windows 2012" is also set. Before that commit
> > > > > > > just setting "acpi_osi=!Windows 2012" was enough to get
> > > > > > > changing the brightness working.
> > > > > >
> > > > > > small correction: It setting "acpi_osi=!Windows 2012" does
> > > > > > only help when using a kernel with commit 886129a8eebe as
> > > > > > HEAD, with v3.16-rc4 setting
> > > > > > video.brightness_switch_enabled=1 and acpi_osi=!Windows 2012
> > > > > > or just one of them, does not make changing the brightness
> > > > > > work again.
> > > > > 
> > > > > And reverting commit 751109aad583 (ACPI / video: Change the
> > > > > default for video.use_native_backlight to 1) make that last
> > > > > problem go away, right?
> > > > > 
> > > > > We are going to rever commit 886129a8eebe for other reasons, so
> > > > > can you please revert it from 3.16-rc5 on your system and
> > > > > report back?
> > > > Yes, with both 751109aad583 and 886129a8eebe reverted, changing
> > > > the brightness works again.
> > > 
> > > What if you revert 886129a8eebe alone?
> > 
> > I mean, what exactly do you need to pass to the kernel command line
> > in that case to make brightness switching work?
> I need to pass
>   acpi_osi="!Windows 2012" video.brightness_switch_enabled=1 video.use_native_backlight=-1
> 
> If I leave one of these parameters out, the brightness switch stops
> working.

With 886129a8eebe reverted you should not need video.brightness_switch_enabled=1.

Aaron, what do you think?

Rafael

Re: [Regression]: Changing brightness does not work with v3.16-rc4

[Aaron Lu]

On 07/15/2014 03:17 AM, Rafael J. Wysocki wrote:
> On Monday, July 14, 2014 08:56:29 PM Julian Wollrath wrote:
>> Am Mon, 14 Jul 2014 21:10:47 +0200
>> schrieb "Rafael J. Wysocki" <rjw@rjwysocki.net>:
>>
>>> On Monday, July 14, 2014 09:02:34 PM Rafael J. Wysocki wrote:
>>>> On Monday, July 14, 2014 08:34:22 PM Julian Wollrath wrote:
>>>>> Am Mon, 14 Jul 2014 20:21:19 +0200
>>>>> schrieb "Rafael J. Wysocki" <rjw@rjwysocki.net>:
>>>>>
>>>>>> On Saturday, July 12, 2014 06:24:52 PM Julian Wollrath wrote:
>>>>>>> Hi,
>>>>>>>
>>>>>>>> changing the brightness on my Thinkpad X230 with Intel
>>>>>>>> HD4000 graphics, stopped working after commit 886129a8eebe
>>>>>>>> (ACPI / video: change acpi-video brightness_switch_enabled
>>>>>>>> default to 0). Changing it back to 1, fixes the problem, if
>>>>>>>> "acpi_osi=!Windows 2012" is also set. Before that commit
>>>>>>>> just setting "acpi_osi=!Windows 2012" was enough to get
>>>>>>>> changing the brightness working.
>>>>>>>
>>>>>>> small correction: It setting "acpi_osi=!Windows 2012" does
>>>>>>> only help when using a kernel with commit 886129a8eebe as
>>>>>>> HEAD, with v3.16-rc4 setting
>>>>>>> video.brightness_switch_enabled=1 and acpi_osi=!Windows 2012
>>>>>>> or just one of them, does not make changing the brightness
>>>>>>> work again.
>>>>>>
>>>>>> And reverting commit 751109aad583 (ACPI / video: Change the
>>>>>> default for video.use_native_backlight to 1) make that last
>>>>>> problem go away, right?
>>>>>>
>>>>>> We are going to rever commit 886129a8eebe for other reasons, so
>>>>>> can you please revert it from 3.16-rc5 on your system and
>>>>>> report back?
>>>>> Yes, with both 751109aad583 and 886129a8eebe reverted, changing
>>>>> the brightness works again.
>>>>
>>>> What if you revert 886129a8eebe alone?
>>>
>>> I mean, what exactly do you need to pass to the kernel command line
>>> in that case to make brightness switching work?
>> I need to pass
>>   acpi_osi="!Windows 2012" video.brightness_switch_enabled=1 video.use_native_backlight=-1
>>
>> If I leave one of these parameters out, the brightness switch stops
>> working.
> 
> With 886129a8eebe reverted you should not need video.brightness_switch_enabled=1.
> 
> Aaron, what do you think?

I agree.

I suppose Julian is not using an standard GUI so he needs the in kernel
processing of the backlight event. And his laptop has a broken ACPI
interface in Win8 mode, so he also needs the "!Windows 2012" option.

With a standard GUI environment, his system would have only one
interface left: the GPU one and everything should work. But of course,
that may not be his config.

Thanks,
Aaron

Re: [Regression]: Changing brightness does not work with v3.16-rc4

[Rafael J. Wysocki]

On Tuesday, July 15, 2014 02:06:21 PM Aaron Lu wrote:
> On 07/15/2014 03:17 AM, Rafael J. Wysocki wrote:
> > On Monday, July 14, 2014 08:56:29 PM Julian Wollrath wrote:
> >> Am Mon, 14 Jul 2014 21:10:47 +0200
> >> schrieb "Rafael J. Wysocki" <rjw@rjwysocki.net>:
> >>
> >>> On Monday, July 14, 2014 09:02:34 PM Rafael J. Wysocki wrote:
> >>>> On Monday, July 14, 2014 08:34:22 PM Julian Wollrath wrote:
> >>>>> Am Mon, 14 Jul 2014 20:21:19 +0200
> >>>>> schrieb "Rafael J. Wysocki" <rjw@rjwysocki.net>:
> >>>>>
> >>>>>> On Saturday, July 12, 2014 06:24:52 PM Julian Wollrath wrote:
> >>>>>>> Hi,
> >>>>>>>
> >>>>>>>> changing the brightness on my Thinkpad X230 with Intel
> >>>>>>>> HD4000 graphics, stopped working after commit 886129a8eebe
> >>>>>>>> (ACPI / video: change acpi-video brightness_switch_enabled
> >>>>>>>> default to 0). Changing it back to 1, fixes the problem, if
> >>>>>>>> "acpi_osi=!Windows 2012" is also set. Before that commit
> >>>>>>>> just setting "acpi_osi=!Windows 2012" was enough to get
> >>>>>>>> changing the brightness working.
> >>>>>>>
> >>>>>>> small correction: It setting "acpi_osi=!Windows 2012" does
> >>>>>>> only help when using a kernel with commit 886129a8eebe as
> >>>>>>> HEAD, with v3.16-rc4 setting
> >>>>>>> video.brightness_switch_enabled=1 and acpi_osi=!Windows 2012
> >>>>>>> or just one of them, does not make changing the brightness
> >>>>>>> work again.
> >>>>>>
> >>>>>> And reverting commit 751109aad583 (ACPI / video: Change the
> >>>>>> default for video.use_native_backlight to 1) make that last
> >>>>>> problem go away, right?
> >>>>>>
> >>>>>> We are going to rever commit 886129a8eebe for other reasons, so
> >>>>>> can you please revert it from 3.16-rc5 on your system and
> >>>>>> report back?
> >>>>> Yes, with both 751109aad583 and 886129a8eebe reverted, changing
> >>>>> the brightness works again.
> >>>>
> >>>> What if you revert 886129a8eebe alone?
> >>>
> >>> I mean, what exactly do you need to pass to the kernel command line
> >>> in that case to make brightness switching work?
> >> I need to pass
> >>   acpi_osi="!Windows 2012" video.brightness_switch_enabled=1 video.use_native_backlight=-1
> >>
> >> If I leave one of these parameters out, the brightness switch stops
> >> working.
> > 
> > With 886129a8eebe reverted you should not need video.brightness_switch_enabled=1.
> > 
> > Aaron, what do you think?
> 
> I agree.
> 
> I suppose Julian is not using an standard GUI so he needs the in kernel
> processing of the backlight event. And his laptop has a broken ACPI
> interface in Win8 mode, so he also needs the "!Windows 2012" option.
> 
> With a standard GUI environment, his system would have only one
> interface left: the GPU one and everything should work. But of course,
> that may not be his config.

Well, do we need to revert 751109aad583 too, then?

It seems that it may break other systems without a desktop environment, may it not?

Rafael

Re: [Regression]: Changing brightness does not work with v3.16-rc4

[Aaron Lu]

On 07/15/2014 08:27 PM, Rafael J. Wysocki wrote:
> On Tuesday, July 15, 2014 02:06:21 PM Aaron Lu wrote:
>> On 07/15/2014 03:17 AM, Rafael J. Wysocki wrote:
>>> On Monday, July 14, 2014 08:56:29 PM Julian Wollrath wrote:
>>>> Am Mon, 14 Jul 2014 21:10:47 +0200
>>>> schrieb "Rafael J. Wysocki" <rjw@rjwysocki.net>:
>>>>
>>>>> On Monday, July 14, 2014 09:02:34 PM Rafael J. Wysocki wrote:
>>>>>> On Monday, July 14, 2014 08:34:22 PM Julian Wollrath wrote:
>>>>>>> Am Mon, 14 Jul 2014 20:21:19 +0200
>>>>>>> schrieb "Rafael J. Wysocki" <rjw@rjwysocki.net>:
>>>>>>>
>>>>>>>> On Saturday, July 12, 2014 06:24:52 PM Julian Wollrath wrote:
>>>>>>>>> Hi,
>>>>>>>>>
>>>>>>>>>> changing the brightness on my Thinkpad X230 with Intel
>>>>>>>>>> HD4000 graphics, stopped working after commit 886129a8eebe
>>>>>>>>>> (ACPI / video: change acpi-video brightness_switch_enabled
>>>>>>>>>> default to 0). Changing it back to 1, fixes the problem, if
>>>>>>>>>> "acpi_osi=!Windows 2012" is also set. Before that commit
>>>>>>>>>> just setting "acpi_osi=!Windows 2012" was enough to get
>>>>>>>>>> changing the brightness working.
>>>>>>>>>
>>>>>>>>> small correction: It setting "acpi_osi=!Windows 2012" does
>>>>>>>>> only help when using a kernel with commit 886129a8eebe as
>>>>>>>>> HEAD, with v3.16-rc4 setting
>>>>>>>>> video.brightness_switch_enabled=1 and acpi_osi=!Windows 2012
>>>>>>>>> or just one of them, does not make changing the brightness
>>>>>>>>> work again.
>>>>>>>>
>>>>>>>> And reverting commit 751109aad583 (ACPI / video: Change the
>>>>>>>> default for video.use_native_backlight to 1) make that last
>>>>>>>> problem go away, right?
>>>>>>>>
>>>>>>>> We are going to rever commit 886129a8eebe for other reasons, so
>>>>>>>> can you please revert it from 3.16-rc5 on your system and
>>>>>>>> report back?
>>>>>>> Yes, with both 751109aad583 and 886129a8eebe reverted, changing
>>>>>>> the brightness works again.
>>>>>>
>>>>>> What if you revert 886129a8eebe alone?
>>>>>
>>>>> I mean, what exactly do you need to pass to the kernel command line
>>>>> in that case to make brightness switching work?
>>>> I need to pass
>>>>   acpi_osi="!Windows 2012" video.brightness_switch_enabled=1 video.use_native_backlight=-1
>>>>
>>>> If I leave one of these parameters out, the brightness switch stops
>>>> working.
>>>
>>> With 886129a8eebe reverted you should not need video.brightness_switch_enabled=1.
>>>
>>> Aaron, what do you think?
>>
>> I agree.
>>
>> I suppose Julian is not using an standard GUI so he needs the in kernel
>> processing of the backlight event. And his laptop has a broken ACPI
>> interface in Win8 mode, so he also needs the "!Windows 2012" option.
>>
>> With a standard GUI environment, his system would have only one
>> interface left: the GPU one and everything should work. But of course,
>> that may not be his config.
> 
> Well, do we need to revert 751109aad583 too, then?
> 
> It seems that it may break other systems without a desktop environment, may it not?

If we have to consider the following config:
1 ACPI backlight interface works(or can work with some cmdline option);
2 Not using a normal GUI(depends on ACPI video module to do the in
  kernel backlight level change on hotkey press).
Then we will need to revert 751109aad583.

Thanks,
Aaron

Re: [Regression]: Changing brightness does not work with v3.16-rc4

[Hans de Goede]

Hi,

On 07/15/2014 02:27 PM, Rafael J. Wysocki wrote:
> On Tuesday, July 15, 2014 02:06:21 PM Aaron Lu wrote:
>> On 07/15/2014 03:17 AM, Rafael J. Wysocki wrote:
>>> On Monday, July 14, 2014 08:56:29 PM Julian Wollrath wrote:
>>>> Am Mon, 14 Jul 2014 21:10:47 +0200
>>>> schrieb "Rafael J. Wysocki" <rjw@rjwysocki.net>:
>>>>
>>>>> On Monday, July 14, 2014 09:02:34 PM Rafael J. Wysocki wrote:
>>>>>> On Monday, July 14, 2014 08:34:22 PM Julian Wollrath wrote:
>>>>>>> Am Mon, 14 Jul 2014 20:21:19 +0200
>>>>>>> schrieb "Rafael J. Wysocki" <rjw@rjwysocki.net>:
>>>>>>>
>>>>>>>> On Saturday, July 12, 2014 06:24:52 PM Julian Wollrath wrote:
>>>>>>>>> Hi,
>>>>>>>>>
>>>>>>>>>> changing the brightness on my Thinkpad X230 with Intel
>>>>>>>>>> HD4000 graphics, stopped working after commit 886129a8eebe
>>>>>>>>>> (ACPI / video: change acpi-video brightness_switch_enabled
>>>>>>>>>> default to 0). Changing it back to 1, fixes the problem, if
>>>>>>>>>> "acpi_osi=!Windows 2012" is also set. Before that commit
>>>>>>>>>> just setting "acpi_osi=!Windows 2012" was enough to get
>>>>>>>>>> changing the brightness working.
>>>>>>>>>
>>>>>>>>> small correction: It setting "acpi_osi=!Windows 2012" does
>>>>>>>>> only help when using a kernel with commit 886129a8eebe as
>>>>>>>>> HEAD, with v3.16-rc4 setting
>>>>>>>>> video.brightness_switch_enabled=1 and acpi_osi=!Windows 2012
>>>>>>>>> or just one of them, does not make changing the brightness
>>>>>>>>> work again.
>>>>>>>>
>>>>>>>> And reverting commit 751109aad583 (ACPI / video: Change the
>>>>>>>> default for video.use_native_backlight to 1) make that last
>>>>>>>> problem go away, right?
>>>>>>>>
>>>>>>>> We are going to rever commit 886129a8eebe for other reasons, so
>>>>>>>> can you please revert it from 3.16-rc5 on your system and
>>>>>>>> report back?
>>>>>>> Yes, with both 751109aad583 and 886129a8eebe reverted, changing
>>>>>>> the brightness works again.
>>>>>>
>>>>>> What if you revert 886129a8eebe alone?
>>>>>
>>>>> I mean, what exactly do you need to pass to the kernel command line
>>>>> in that case to make brightness switching work?
>>>> I need to pass
>>>>    acpi_osi="!Windows 2012" video.brightness_switch_enabled=1 video.use_native_backlight=-1
>>>>
>>>> If I leave one of these parameters out, the brightness switch stops
>>>> working.
>>>
>>> With 886129a8eebe reverted you should not need video.brightness_switch_enabled=1.
>>>
>>> Aaron, what do you think?
>>
>> I agree.
>>
>> I suppose Julian is not using an standard GUI so he needs the in kernel
>> processing of the backlight event. And his laptop has a broken ACPI
>> interface in Win8 mode, so he also needs the "!Windows 2012" option.
>>
>> With a standard GUI environment, his system would have only one
>> interface left: the GPU one and everything should work. But of course,
>> that may not be his config.
>
> Well, do we need to revert 751109aad583 too, then?

No, just no, clearly using the acpi video interface for backlight control
is the wrong thing to do on win8 generation laptops, if we don't flip
the default we're going to end up with a never ending list of quirks
for models where the acpi-video interface is broken.

On 07/15/2014 04:00 PM, Aaron Lu wrote:

 > If we have to consider the following config:
 > 1 ACPI backlight interface works(or can work with some cmdline option);

And the BIOS advertises native win8 support.

 > 2 Not using a normal GUI(depends on ACPI video module to do the in
 >    kernel backlight level change on hotkey press).
 > Then we will need to revert 751109aad583.

I think the combination of 1 and 2 makes the subset of users
potentially affected by this so small, that we really should
continue with video.use_native_backlight=1 as default, the
other route adding more and more and more and more quirks
is sheer madness.

Regards,

Hans

Re: [Regression]: Changing brightness does not work with v3.16-rc4

[Aaron Lu]

On 07/15/2014 10:05 PM, Hans de Goede wrote:
> Hi,
> 
> On 07/15/2014 02:27 PM, Rafael J. Wysocki wrote:
>> On Tuesday, July 15, 2014 02:06:21 PM Aaron Lu wrote:
>>> On 07/15/2014 03:17 AM, Rafael J. Wysocki wrote:
>>>> On Monday, July 14, 2014 08:56:29 PM Julian Wollrath wrote:
>>>>> Am Mon, 14 Jul 2014 21:10:47 +0200
>>>>> schrieb "Rafael J. Wysocki" <rjw@rjwysocki.net>:
>>>>>
>>>>>> On Monday, July 14, 2014 09:02:34 PM Rafael J. Wysocki wrote:
>>>>>>> On Monday, July 14, 2014 08:34:22 PM Julian Wollrath wrote:
>>>>>>>> Am Mon, 14 Jul 2014 20:21:19 +0200
>>>>>>>> schrieb "Rafael J. Wysocki" <rjw@rjwysocki.net>:
>>>>>>>>
>>>>>>>>> On Saturday, July 12, 2014 06:24:52 PM Julian Wollrath wrote:
>>>>>>>>>> Hi,
>>>>>>>>>>
>>>>>>>>>>> changing the brightness on my Thinkpad X230 with Intel
>>>>>>>>>>> HD4000 graphics, stopped working after commit 886129a8eebe
>>>>>>>>>>> (ACPI / video: change acpi-video brightness_switch_enabled
>>>>>>>>>>> default to 0). Changing it back to 1, fixes the problem, if
>>>>>>>>>>> "acpi_osi=!Windows 2012" is also set. Before that commit
>>>>>>>>>>> just setting "acpi_osi=!Windows 2012" was enough to get
>>>>>>>>>>> changing the brightness working.
>>>>>>>>>>
>>>>>>>>>> small correction: It setting "acpi_osi=!Windows 2012" does
>>>>>>>>>> only help when using a kernel with commit 886129a8eebe as
>>>>>>>>>> HEAD, with v3.16-rc4 setting
>>>>>>>>>> video.brightness_switch_enabled=1 and acpi_osi=!Windows 2012
>>>>>>>>>> or just one of them, does not make changing the brightness
>>>>>>>>>> work again.
>>>>>>>>>
>>>>>>>>> And reverting commit 751109aad583 (ACPI / video: Change the
>>>>>>>>> default for video.use_native_backlight to 1) make that last
>>>>>>>>> problem go away, right?
>>>>>>>>>
>>>>>>>>> We are going to rever commit 886129a8eebe for other reasons, so
>>>>>>>>> can you please revert it from 3.16-rc5 on your system and
>>>>>>>>> report back?
>>>>>>>> Yes, with both 751109aad583 and 886129a8eebe reverted, changing
>>>>>>>> the brightness works again.
>>>>>>>
>>>>>>> What if you revert 886129a8eebe alone?
>>>>>>
>>>>>> I mean, what exactly do you need to pass to the kernel command line
>>>>>> in that case to make brightness switching work?
>>>>> I need to pass
>>>>>    acpi_osi="!Windows 2012" video.brightness_switch_enabled=1 video.use_native_backlight=-1
>>>>>
>>>>> If I leave one of these parameters out, the brightness switch stops
>>>>> working.
>>>>
>>>> With 886129a8eebe reverted you should not need video.brightness_switch_enabled=1.
>>>>
>>>> Aaron, what do you think?
>>>
>>> I agree.
>>>
>>> I suppose Julian is not using an standard GUI so he needs the in kernel
>>> processing of the backlight event. And his laptop has a broken ACPI
>>> interface in Win8 mode, so he also needs the "!Windows 2012" option.
>>>
>>> With a standard GUI environment, his system would have only one
>>> interface left: the GPU one and everything should work. But of course,
>>> that may not be his config.
>>
>> Well, do we need to revert 751109aad583 too, then?
> 
> No, just no, clearly using the acpi video interface for backlight control
> is the wrong thing to do on win8 generation laptops, if we don't flip
> the default we're going to end up with a never ending list of quirks
> for models where the acpi-video interface is broken.
> 
> On 07/15/2014 04:00 PM, Aaron Lu wrote:
> 
>  > If we have to consider the following config:
>  > 1 ACPI backlight interface works(or can work with some cmdline option);
> 
> And the BIOS advertises native win8 support.

Right.
So this condition should be:
1 ACPI backlight interface works in Win8 mode;

This means, for Julian's system, the commit 751109aad583 doesn't need to
be reverted as the ACPI backlight interface on his system only works
when the acpi_osi="!Windows 2012" is added. In that case, the
video.use_native_backlight=X doesn't make any difference anymore.

Thanks,
Aaron

> 
>  > 2 Not using a normal GUI(depends on ACPI video module to do the in
>  >    kernel backlight level change on hotkey press).
>  > Then we will need to revert 751109aad583.
> 
> I think the combination of 1 and 2 makes the subset of users
> potentially affected by this so small, that we really should
> continue with video.use_native_backlight=1 as default, the
> other route adding more and more and more and more quirks
> is sheer madness.
> 
> Regards,
> 
> Hans
> 
> 
> 

Re: [Regression]: Changing brightness does not work with v3.16-rc4

[Julian Wollrath]

Am Tue, 15 Jul 2014 14:06:21 +0800
schrieb Aaron Lu <aaron.lu@intel.com>:

> On 07/15/2014 03:17 AM, Rafael J. Wysocki wrote:
> > On Monday, July 14, 2014 08:56:29 PM Julian Wollrath wrote:
> >> Am Mon, 14 Jul 2014 21:10:47 +0200
> >> schrieb "Rafael J. Wysocki" <rjw@rjwysocki.net>:
> >>
> >>> On Monday, July 14, 2014 09:02:34 PM Rafael J. Wysocki wrote:
> >>>> On Monday, July 14, 2014 08:34:22 PM Julian Wollrath wrote:
> >>>>> Am Mon, 14 Jul 2014 20:21:19 +0200
> >>>>> schrieb "Rafael J. Wysocki" <rjw@rjwysocki.net>:
> >>>>>
> >>>>>> On Saturday, July 12, 2014 06:24:52 PM Julian Wollrath wrote:
> >>>>>>> Hi,
> >>>>>>>
> >>>>>>>> changing the brightness on my Thinkpad X230 with Intel
> >>>>>>>> HD4000 graphics, stopped working after commit 886129a8eebe
> >>>>>>>> (ACPI / video: change acpi-video brightness_switch_enabled
> >>>>>>>> default to 0). Changing it back to 1, fixes the problem, if
> >>>>>>>> "acpi_osi=!Windows 2012" is also set. Before that commit
> >>>>>>>> just setting "acpi_osi=!Windows 2012" was enough to get
> >>>>>>>> changing the brightness working.
> >>>>>>>
> >>>>>>> small correction: It setting "acpi_osi=!Windows 2012" does
> >>>>>>> only help when using a kernel with commit 886129a8eebe as
> >>>>>>> HEAD, with v3.16-rc4 setting
> >>>>>>> video.brightness_switch_enabled=1 and acpi_osi=!Windows 2012
> >>>>>>> or just one of them, does not make changing the brightness
> >>>>>>> work again.
> >>>>>>
> >>>>>> And reverting commit 751109aad583 (ACPI / video: Change the
> >>>>>> default for video.use_native_backlight to 1) make that last
> >>>>>> problem go away, right?
> >>>>>>
> >>>>>> We are going to rever commit 886129a8eebe for other reasons, so
> >>>>>> can you please revert it from 3.16-rc5 on your system and
> >>>>>> report back?
> >>>>> Yes, with both 751109aad583 and 886129a8eebe reverted, changing
> >>>>> the brightness works again.
> >>>>
> >>>> What if you revert 886129a8eebe alone?
> >>>
> >>> I mean, what exactly do you need to pass to the kernel command
> >>> line in that case to make brightness switching work?
> >> I need to pass
> >>   acpi_osi="!Windows 2012" video.brightness_switch_enabled=1
> >> video.use_native_backlight=-1
> >>
> >> If I leave one of these parameters out, the brightness switch stops
> >> working.
> > 
> > With 886129a8eebe reverted you should not need
> > video.brightness_switch_enabled=1.
> > 
> > Aaron, what do you think?
> 
> I agree.
> 
> I suppose Julian is not using an standard GUI so he needs the in
> kernel processing of the backlight event.
If you consider just using a window manager and not a full blown DE not
using a standard GUI, than your hunch is right.

> And his laptop has a broken
> ACPI interface in Win8 mode, so he also needs the "!Windows 2012"
> option.
> 
> With a standard GUI environment, his system would have only one
> interface left: the GPU one and everything should work. But of course,
> that may not be his config.
> 
> Thanks,
> Aaron

Re: [Regression]: Changing brightness does not work with v3.16-rc4

[Rafael J. Wysocki]

On Tuesday, July 15, 2014 10:45:29 PM Aaron Lu wrote:
> On 07/15/2014 10:05 PM, Hans de Goede wrote:

[cut]

> > On 07/15/2014 04:00 PM, Aaron Lu wrote:
> > 
> >  > If we have to consider the following config:
> >  > 1 ACPI backlight interface works(or can work with some cmdline option);
> > 
> > And the BIOS advertises native win8 support.
> 
> Right.
> So this condition should be:
> 1 ACPI backlight interface works in Win8 mode;
> 
> This means, for Julian's system, the commit 751109aad583 doesn't need to
> be reverted as the ACPI backlight interface on his system only works
> when the acpi_osi="!Windows 2012" is added. In that case, the
> video.use_native_backlight=X doesn't make any difference anymore.

But Julian reports that he needs to revert that commit to make things work
as before for him.  What gives?

Rafael

Re: [Regression]: Changing brightness does not work with v3.16-rc4

[Aaron Lu]

On 07/15/2014 02:56 AM, Julian Wollrath wrote:
> Am Mon, 14 Jul 2014 21:10:47 +0200
> schrieb "Rafael J. Wysocki" <rjw@rjwysocki.net>:
> 
>> On Monday, July 14, 2014 09:02:34 PM Rafael J. Wysocki wrote:
>>> On Monday, July 14, 2014 08:34:22 PM Julian Wollrath wrote:
>>>> Am Mon, 14 Jul 2014 20:21:19 +0200
>>>> schrieb "Rafael J. Wysocki" <rjw@rjwysocki.net>:
>>>>
>>>>> On Saturday, July 12, 2014 06:24:52 PM Julian Wollrath wrote:
>>>>>> Hi,
>>>>>>
>>>>>>> changing the brightness on my Thinkpad X230 with Intel
>>>>>>> HD4000 graphics, stopped working after commit 886129a8eebe
>>>>>>> (ACPI / video: change acpi-video brightness_switch_enabled
>>>>>>> default to 0). Changing it back to 1, fixes the problem, if
>>>>>>> "acpi_osi=!Windows 2012" is also set. Before that commit
>>>>>>> just setting "acpi_osi=!Windows 2012" was enough to get
>>>>>>> changing the brightness working.
>>>>>>
>>>>>> small correction: It setting "acpi_osi=!Windows 2012" does
>>>>>> only help when using a kernel with commit 886129a8eebe as
>>>>>> HEAD, with v3.16-rc4 setting
>>>>>> video.brightness_switch_enabled=1 and acpi_osi=!Windows 2012
>>>>>> or just one of them, does not make changing the brightness
>>>>>> work again.
>>>>>
>>>>> And reverting commit 751109aad583 (ACPI / video: Change the
>>>>> default for video.use_native_backlight to 1) make that last
>>>>> problem go away, right?
>>>>>
>>>>> We are going to rever commit 886129a8eebe for other reasons, so
>>>>> can you please revert it from 3.16-rc5 on your system and
>>>>> report back?
>>>> Yes, with both 751109aad583 and 886129a8eebe reverted, changing
>>>> the brightness works again.
>>>
>>> What if you revert 886129a8eebe alone?
>>
>> I mean, what exactly do you need to pass to the kernel command line
>> in that case to make brightness switching work?
> I need to pass
>   acpi_osi="!Windows 2012" video.brightness_switch_enabled=1 video.use_native_backlight=-1
> 
> If I leave one of these parameters out, the brightness switch stops
> working.

If you only pass the following 2 cmdline options:
acpi_osi="!Windows 2012" video.brightness_switch_enabled=1
Will there be the /sys/class/backlight/acpi_videoX file?

Thanks,
Aaron

Re: [Regression]: Changing brightness does not work with v3.16-rc4

[Hans de Goede]

Hi,

On 07/16/2014 02:43 AM, Rafael J. Wysocki wrote:
> On Tuesday, July 15, 2014 10:45:29 PM Aaron Lu wrote:
>> On 07/15/2014 10:05 PM, Hans de Goede wrote:
> 
> [cut]
> 
>>> On 07/15/2014 04:00 PM, Aaron Lu wrote:
>>>
>>>  > If we have to consider the following config:
>>>  > 1 ACPI backlight interface works(or can work with some cmdline option);
>>>
>>> And the BIOS advertises native win8 support.
>>
>> Right.
>> So this condition should be:
>> 1 ACPI backlight interface works in Win8 mode;
>>
>> This means, for Julian's system, the commit 751109aad583 doesn't need to
>> be reverted as the ACPI backlight interface on his system only works
>> when the acpi_osi="!Windows 2012" is added. In that case, the
>> video.use_native_backlight=X doesn't make any difference anymore.
> 
> But Julian reports that he needs to revert that commit to make things work
> as before for him.  What gives?

Likely what is happening is that this commit is still affecting Julian because
we check if the bios is advertising win8 support, not if we are advertising win8
support ourselves.

Julian, I've jumped into this thread halfway, so I'm not 100% clear on your
original problem. From what I've read sofar you need acpi_osi="!Windows 2012"
for backlight control to work. That in itself is a sign that things are not
as they should be, and this is actually what the new default of
video.use_native_backlight=1 is trying to fix.

If you boot the new kernel without acpi_osi="!Windows 2012" and without
video.use_native_backlight=X (so using the new default of
video.use_native_backlight=1), what does ls /sys/class/backlight say then ?

If there is a directory in there can you then cd in to that directory,
and do: "cat max_brightness" and then "echo value > brightness" (the latter
as root) with value being a number, once half of max_brightness, once
full brightness and see if this controls your backlight brightness.

Assuming this test succeeds, is your problem resolved then? And if not
what is the problem?

Regards,

Hans

Re: [Regression]: Changing brightness does not work with v3.16-rc4

[Aaron Lu]

On 07/16/2014 02:29 PM, Hans de Goede wrote:
> Hi,
> 
> On 07/16/2014 02:43 AM, Rafael J. Wysocki wrote:
>> On Tuesday, July 15, 2014 10:45:29 PM Aaron Lu wrote:
>>> On 07/15/2014 10:05 PM, Hans de Goede wrote:
>>
>> [cut]
>>
>>>> On 07/15/2014 04:00 PM, Aaron Lu wrote:
>>>>
>>>>  > If we have to consider the following config:
>>>>  > 1 ACPI backlight interface works(or can work with some cmdline option);
>>>>
>>>> And the BIOS advertises native win8 support.
>>>
>>> Right.
>>> So this condition should be:
>>> 1 ACPI backlight interface works in Win8 mode;
>>>
>>> This means, for Julian's system, the commit 751109aad583 doesn't need to
>>> be reverted as the ACPI backlight interface on his system only works
>>> when the acpi_osi="!Windows 2012" is added. In that case, the
>>> video.use_native_backlight=X doesn't make any difference anymore.
>>
>> But Julian reports that he needs to revert that commit to make things work
>> as before for him.  What gives?
> 
> Likely what is happening is that this commit is still affecting Julian because
> we check if the bios is advertising win8 support, not if we are advertising win8
> support ourselves.

Perhaps the firmware on Julian's laptop has _OSI("Windows 2013") and if that
is the case, the acpi_gbl_osi_data will still get the value of ACPI_OSI_WIN_8
and acpi_osi_is_win8() will return true...

Julian,
Please attach your acpidump, thanks.

> 
> Julian, I've jumped into this thread halfway, so I'm not 100% clear on your
> original problem. From what I've read sofar you need acpi_osi="!Windows 2012"
> for backlight control to work. That in itself is a sign that things are not
> as they should be, and this is actually what the new default of
> video.use_native_backlight=1 is trying to fix.
> 
> If you boot the new kernel without acpi_osi="!Windows 2012" and without
> video.use_native_backlight=X (so using the new default of
> video.use_native_backlight=1), what does ls /sys/class/backlight say then ?
> 
> If there is a directory in there can you then cd in to that directory,
> and do: "cat max_brightness" and then "echo value > brightness" (the latter
> as root) with value being a number, once half of max_brightness, once
> full brightness and see if this controls your backlight brightness.
> 
> Assuming this test succeeds, is your problem resolved then? And if not
> what is the problem?

The problem is Julian is using a lightweight GUI that do not respond to
backlight hotkey events. So he needs the in kernel processing of
backlight events and for that to work, he has to add the
acpi_osi="!Windows 2012" cmdline option.

-Aaron

Re: [Regression]: Changing brightness does not work with v3.16-rc4

[Hans de Goede]

Hi,

On 07/16/2014 09:19 AM, Aaron Lu wrote:
> On 07/16/2014 02:29 PM, Hans de Goede wrote:
>> Hi,
>>
>> On 07/16/2014 02:43 AM, Rafael J. Wysocki wrote:
>>> On Tuesday, July 15, 2014 10:45:29 PM Aaron Lu wrote:
>>>> On 07/15/2014 10:05 PM, Hans de Goede wrote:
>>>
>>> [cut]
>>>
>>>>> On 07/15/2014 04:00 PM, Aaron Lu wrote:
>>>>>
>>>>>  > If we have to consider the following config:
>>>>>  > 1 ACPI backlight interface works(or can work with some cmdline option);
>>>>>
>>>>> And the BIOS advertises native win8 support.
>>>>
>>>> Right.
>>>> So this condition should be:
>>>> 1 ACPI backlight interface works in Win8 mode;
>>>>
>>>> This means, for Julian's system, the commit 751109aad583 doesn't need to
>>>> be reverted as the ACPI backlight interface on his system only works
>>>> when the acpi_osi="!Windows 2012" is added. In that case, the
>>>> video.use_native_backlight=X doesn't make any difference anymore.
>>>
>>> But Julian reports that he needs to revert that commit to make things work
>>> as before for him.  What gives?
>>
>> Likely what is happening is that this commit is still affecting Julian because
>> we check if the bios is advertising win8 support, not if we are advertising win8
>> support ourselves.
> 
> Perhaps the firmware on Julian's laptop has _OSI("Windows 2013") and if that
> is the case, the acpi_gbl_osi_data will still get the value of ACPI_OSI_WIN_8
> and acpi_osi_is_win8() will return true...
> 
> Julian,
> Please attach your acpidump, thanks.
> 
>>
>> Julian, I've jumped into this thread halfway, so I'm not 100% clear on your
>> original problem. From what I've read sofar you need acpi_osi="!Windows 2012"
>> for backlight control to work. That in itself is a sign that things are not
>> as they should be, and this is actually what the new default of
>> video.use_native_backlight=1 is trying to fix.
>>
>> If you boot the new kernel without acpi_osi="!Windows 2012" and without
>> video.use_native_backlight=X (so using the new default of
>> video.use_native_backlight=1), what does ls /sys/class/backlight say then ?
>>
>> If there is a directory in there can you then cd in to that directory,
>> and do: "cat max_brightness" and then "echo value > brightness" (the latter
>> as root) with value being a number, once half of max_brightness, once
>> full brightness and see if this controls your backlight brightness.
>>
>> Assuming this test succeeds, is your problem resolved then? And if not
>> what is the problem?
> 
> The problem is Julian is using a lightweight GUI that do not respond to
> backlight hotkey events. So he needs the in kernel processing of
> backlight events and for that to work, he has to add the
> acpi_osi="!Windows 2012" cmdline option.

I really think we don't want people like Julian to be passing
acpi_osi="!Windows 2012", just so that they may get a working acpi-video
backlight control (and possible a dozen of bad side-effects), just so that
they can use the brightness_switch_enabled=1 key processing.

AFAIK we all agree that the best way forward with backlight control on
Windows 8 laptops is not using acpi_osi="!Windows 2012", as that is a way
too big hammer, instead video.use_native_backlight=1 should be used which
is why we are making this the default in 3.16.

I realize that this does not fix Julian's problem. As I see it there are
2 separate problems here:

1) backlight control issues on Windows 8 laptops, this is what we are
trying to solve with video.use_native_backlight=1 (and without using
any acpi_osi override)

2) Some component in the stack needs to responds to backlight key-presses
and actually use the backlight control to change the backlight setting,
normally this is done by gnome / kde / unity / xfce, but what about users
not running those? For some of those users brightness_switch_enabled=1
has been making things work for them, but that only works if acpi-video
controls the backlight, which it does not do everywhere, and which we
want to get away from for Windows 8 laptops since it is just too broken
there.

Note that 2. is not limited to Windows 8 laptops / acpi-video in any
way, we've 23 non acpi-video backlight drivers under drivers/platform/x86/
alone + the native gpu backlight drivers. So what we really need is a
solution for any laptop not using acpi-video for backlight control and
not running one of the big 4 desktop environments.

Note that we pretty much have the same problem for any acpi event,
power button pressed, lid closed, etc. are all "key press" type
events typically handles by the desktop enviroment (e.g. we don't
automatically suspend on lid-close, we just tell userspace). And we already
have a solution for these type of events when running a desktop environment
which handles them, these get handled by acpid. So to me it seems that
the obvious (and one and only right) way to fix this is to teach acpid
to deal with brightness key-presses.

I'm willing to write a patch for acpid to implement this, and then
Julian's setup should just work without needing any special kernel
commandline options.

Julian would that be an acceptable solution for you, and would you be
willing to test such a patch ?

Regards,

Hans

Re: [Regression]: Changing brightness does not work with v3.16-rc4

[Aaron Lu]

On 07/16/2014 04:13 PM, Hans de Goede wrote:
> Hi,
> 
> On 07/16/2014 09:19 AM, Aaron Lu wrote:
>> On 07/16/2014 02:29 PM, Hans de Goede wrote:
>>> Hi,
>>>
>>> On 07/16/2014 02:43 AM, Rafael J. Wysocki wrote:
>>>> On Tuesday, July 15, 2014 10:45:29 PM Aaron Lu wrote:
>>>>> On 07/15/2014 10:05 PM, Hans de Goede wrote:
>>>>
>>>> [cut]
>>>>
>>>>>> On 07/15/2014 04:00 PM, Aaron Lu wrote:
>>>>>>
>>>>>>  > If we have to consider the following config:
>>>>>>  > 1 ACPI backlight interface works(or can work with some cmdline option);
>>>>>>
>>>>>> And the BIOS advertises native win8 support.
>>>>>
>>>>> Right.
>>>>> So this condition should be:
>>>>> 1 ACPI backlight interface works in Win8 mode;
>>>>>
>>>>> This means, for Julian's system, the commit 751109aad583 doesn't need to
>>>>> be reverted as the ACPI backlight interface on his system only works
>>>>> when the acpi_osi="!Windows 2012" is added. In that case, the
>>>>> video.use_native_backlight=X doesn't make any difference anymore.
>>>>
>>>> But Julian reports that he needs to revert that commit to make things work
>>>> as before for him.  What gives?
>>>
>>> Likely what is happening is that this commit is still affecting Julian because
>>> we check if the bios is advertising win8 support, not if we are advertising win8
>>> support ourselves.
>>
>> Perhaps the firmware on Julian's laptop has _OSI("Windows 2013") and if that
>> is the case, the acpi_gbl_osi_data will still get the value of ACPI_OSI_WIN_8
>> and acpi_osi_is_win8() will return true...
>>
>> Julian,
>> Please attach your acpidump, thanks.
>>
>>>
>>> Julian, I've jumped into this thread halfway, so I'm not 100% clear on your
>>> original problem. From what I've read sofar you need acpi_osi="!Windows 2012"
>>> for backlight control to work. That in itself is a sign that things are not
>>> as they should be, and this is actually what the new default of
>>> video.use_native_backlight=1 is trying to fix.
>>>
>>> If you boot the new kernel without acpi_osi="!Windows 2012" and without
>>> video.use_native_backlight=X (so using the new default of
>>> video.use_native_backlight=1), what does ls /sys/class/backlight say then ?
>>>
>>> If there is a directory in there can you then cd in to that directory,
>>> and do: "cat max_brightness" and then "echo value > brightness" (the latter
>>> as root) with value being a number, once half of max_brightness, once
>>> full brightness and see if this controls your backlight brightness.
>>>
>>> Assuming this test succeeds, is your problem resolved then? And if not
>>> what is the problem?
>>
>> The problem is Julian is using a lightweight GUI that do not respond to
>> backlight hotkey events. So he needs the in kernel processing of
>> backlight events and for that to work, he has to add the
>> acpi_osi="!Windows 2012" cmdline option.
> 
> I really think we don't want people like Julian to be passing
> acpi_osi="!Windows 2012", just so that they may get a working acpi-video
> backlight control (and possible a dozen of bad side-effects), just so that
> they can use the brightness_switch_enabled=1 key processing.

Indeed.

> 
> AFAIK we all agree that the best way forward with backlight control on
> Windows 8 laptops is not using acpi_osi="!Windows 2012", as that is a way
> too big hammer, instead video.use_native_backlight=1 should be used which
> is why we are making this the default in 3.16.

I still agree with this.

Regards,
Aaron

> 
> I realize that this does not fix Julian's problem. As I see it there are
> 2 separate problems here:
> 
> 1) backlight control issues on Windows 8 laptops, this is what we are
> trying to solve with video.use_native_backlight=1 (and without using
> any acpi_osi override)
> 
> 2) Some component in the stack needs to responds to backlight key-presses
> and actually use the backlight control to change the backlight setting,
> normally this is done by gnome / kde / unity / xfce, but what about users
> not running those? For some of those users brightness_switch_enabled=1
> has been making things work for them, but that only works if acpi-video
> controls the backlight, which it does not do everywhere, and which we
> want to get away from for Windows 8 laptops since it is just too broken
> there.
> 
> Note that 2. is not limited to Windows 8 laptops / acpi-video in any
> way, we've 23 non acpi-video backlight drivers under drivers/platform/x86/
> alone + the native gpu backlight drivers. So what we really need is a
> solution for any laptop not using acpi-video for backlight control and
> not running one of the big 4 desktop environments.
> 
> Note that we pretty much have the same problem for any acpi event,
> power button pressed, lid closed, etc. are all "key press" type
> events typically handles by the desktop enviroment (e.g. we don't
> automatically suspend on lid-close, we just tell userspace). And we already
> have a solution for these type of events when running a desktop environment
> which handles them, these get handled by acpid. So to me it seems that
> the obvious (and one and only right) way to fix this is to teach acpid
> to deal with brightness key-presses.
> 
> I'm willing to write a patch for acpid to implement this, and then
> Julian's setup should just work without needing any special kernel
> commandline options.
> 
> Julian would that be an acceptable solution for you, and would you be
> willing to test such a patch ?
> 
> Regards,
> 
> Hans
> 

Re: [Regression]: Changing brightness does not work with v3.16-rc4

[Hans de Goede]

Hi,

On 07/16/2014 10:13 AM, Hans de Goede wrote:

<snip>

> I realize that this does not fix Julian's problem. As I see it there are
> 2 separate problems here:
> 
> 1) backlight control issues on Windows 8 laptops, this is what we are
> trying to solve with video.use_native_backlight=1 (and without using
> any acpi_osi override)
> 
> 2) Some component in the stack needs to responds to backlight key-presses
> and actually use the backlight control to change the backlight setting,
> normally this is done by gnome / kde / unity / xfce, but what about users
> not running those? For some of those users brightness_switch_enabled=1
> has been making things work for them, but that only works if acpi-video
> controls the backlight, which it does not do everywhere, and which we
> want to get away from for Windows 8 laptops since it is just too broken
> there.
> 
> Note that 2. is not limited to Windows 8 laptops / acpi-video in any
> way, we've 23 non acpi-video backlight drivers under drivers/platform/x86/
> alone + the native gpu backlight drivers. So what we really need is a
> solution for any laptop not using acpi-video for backlight control and
> not running one of the big 4 desktop environments.
> 
> Note that we pretty much have the same problem for any acpi event,
> power button pressed, lid closed, etc. are all "key press" type
> events typically handles by the desktop enviroment (e.g. we don't
> automatically suspend on lid-close, we just tell userspace). And we already
> have a solution for these type of events when running a desktop environment
> which handles them, these get handled by acpid. So to me it seems that

s/handles/does not handle/  small but important typo.

> the obvious (and one and only right) way to fix this is to teach acpid
> to deal with brightness key-presses.
> 
> I'm willing to write a patch for acpid to implement this, and then
> Julian's setup should just work without needing any special kernel
> commandline options.
> 
> Julian would that be an acceptable solution for you, and would you be
> willing to test such a patch ?

Regards,

Hans

Re: [Regression]: Changing brightness does not work with v3.16-rc4

[Julian Wollrath]

Am Wed, 16 Jul 2014 10:36:56 +0800
schrieb Aaron Lu <aaron.lu@intel.com>:

> On 07/15/2014 02:56 AM, Julian Wollrath wrote:
> > Am Mon, 14 Jul 2014 21:10:47 +0200
> > schrieb "Rafael J. Wysocki" <rjw@rjwysocki.net>:
> > 
> >> On Monday, July 14, 2014 09:02:34 PM Rafael J. Wysocki wrote:
> >>> On Monday, July 14, 2014 08:34:22 PM Julian Wollrath wrote:
> >>>> Am Mon, 14 Jul 2014 20:21:19 +0200
> >>>> schrieb "Rafael J. Wysocki" <rjw@rjwysocki.net>:
> >>>>
> >>>>> On Saturday, July 12, 2014 06:24:52 PM Julian Wollrath wrote:
> >>>>>> Hi,
> >>>>>>
> >>>>>>> changing the brightness on my Thinkpad X230 with Intel
> >>>>>>> HD4000 graphics, stopped working after commit 886129a8eebe
> >>>>>>> (ACPI / video: change acpi-video brightness_switch_enabled
> >>>>>>> default to 0). Changing it back to 1, fixes the problem, if
> >>>>>>> "acpi_osi=!Windows 2012" is also set. Before that commit
> >>>>>>> just setting "acpi_osi=!Windows 2012" was enough to get
> >>>>>>> changing the brightness working.
> >>>>>>
> >>>>>> small correction: It setting "acpi_osi=!Windows 2012" does
> >>>>>> only help when using a kernel with commit 886129a8eebe as
> >>>>>> HEAD, with v3.16-rc4 setting
> >>>>>> video.brightness_switch_enabled=1 and acpi_osi=!Windows 2012
> >>>>>> or just one of them, does not make changing the brightness
> >>>>>> work again.
> >>>>>
> >>>>> And reverting commit 751109aad583 (ACPI / video: Change the
> >>>>> default for video.use_native_backlight to 1) make that last
> >>>>> problem go away, right?
> >>>>>
> >>>>> We are going to rever commit 886129a8eebe for other reasons, so
> >>>>> can you please revert it from 3.16-rc5 on your system and
> >>>>> report back?
> >>>> Yes, with both 751109aad583 and 886129a8eebe reverted, changing
> >>>> the brightness works again.
> >>>
> >>> What if you revert 886129a8eebe alone?
> >>
> >> I mean, what exactly do you need to pass to the kernel command line
> >> in that case to make brightness switching work?
> > I need to pass
> >   acpi_osi="!Windows 2012" video.brightness_switch_enabled=1
> > video.use_native_backlight=-1
> > 
> > If I leave one of these parameters out, the brightness switch stops
> > working.
> 
> If you only pass the following 2 cmdline options:
> acpi_osi="!Windows 2012" video.brightness_switch_enabled=1
> Will there be the /sys/class/backlight/acpi_videoX file?

Yes, and interestingly with v3.16-rc5 the brightness switching works
with just these two options.

Cheers,
Julian

Re: [Regression]: Changing brightness does not work with v3.16-rc4

[Julian Wollrath]

Am Wed, 16 Jul 2014 10:35:33 +0200
schrieb Hans de Goede <hdegoede@redhat.com>:

> Hi,
> 
> On 07/16/2014 10:13 AM, Hans de Goede wrote:
> 
> <snip>
> 
> > I realize that this does not fix Julian's problem. As I see it
> > there are 2 separate problems here:
> > 
> > 1) backlight control issues on Windows 8 laptops, this is what we
> > are trying to solve with video.use_native_backlight=1 (and without
> > using any acpi_osi override)
> > 
> > 2) Some component in the stack needs to responds to backlight
> > key-presses and actually use the backlight control to change the
> > backlight setting, normally this is done by gnome / kde / unity /
> > xfce, but what about users not running those? For some of those
> > users brightness_switch_enabled=1 has been making things work for
> > them, but that only works if acpi-video controls the backlight,
> > which it does not do everywhere, and which we want to get away from
> > for Windows 8 laptops since it is just too broken there.
> > 
> > Note that 2. is not limited to Windows 8 laptops / acpi-video in any
> > way, we've 23 non acpi-video backlight drivers under
> > drivers/platform/x86/ alone + the native gpu backlight drivers. So
> > what we really need is a solution for any laptop not using
> > acpi-video for backlight control and not running one of the big 4
> > desktop environments.
> > 
> > Note that we pretty much have the same problem for any acpi event,
> > power button pressed, lid closed, etc. are all "key press" type
> > events typically handles by the desktop enviroment (e.g. we don't
> > automatically suspend on lid-close, we just tell userspace). And we
> > already have a solution for these type of events when running a
> > desktop environment which handles them, these get handled by acpid.
> > So to me it seems that
> 
> s/handles/does not handle/  small but important typo.
> 
> > the obvious (and one and only right) way to fix this is to teach
> > acpid to deal with brightness key-presses.
> > 
> > I'm willing to write a patch for acpid to implement this, and then
> > Julian's setup should just work without needing any special kernel
> > commandline options.
> > 
> > Julian would that be an acceptable solution for you, and would you
> > be willing to test such a patch ?
Yes, of course that would be an acceptable solution for me and yes, I
would be willing to test such a patch.

Cheers,
Julian

Re: [Regression]: Changing brightness does not work with v3.16-rc4

[Hans de Goede]

Hi,

On 07/16/2014 01:50 PM, Julian Wollrath wrote:
> Am Wed, 16 Jul 2014 10:35:33 +0200
> schrieb Hans de Goede <hdegoede@redhat.com>:
> 
>> Hi,
>>
>> On 07/16/2014 10:13 AM, Hans de Goede wrote:
>>
>> <snip>
>>
>>> I realize that this does not fix Julian's problem. As I see it
>>> there are 2 separate problems here:
>>>
>>> 1) backlight control issues on Windows 8 laptops, this is what we
>>> are trying to solve with video.use_native_backlight=1 (and without
>>> using any acpi_osi override)
>>>
>>> 2) Some component in the stack needs to responds to backlight
>>> key-presses and actually use the backlight control to change the
>>> backlight setting, normally this is done by gnome / kde / unity /
>>> xfce, but what about users not running those? For some of those
>>> users brightness_switch_enabled=1 has been making things work for
>>> them, but that only works if acpi-video controls the backlight,
>>> which it does not do everywhere, and which we want to get away from
>>> for Windows 8 laptops since it is just too broken there.
>>>
>>> Note that 2. is not limited to Windows 8 laptops / acpi-video in any
>>> way, we've 23 non acpi-video backlight drivers under
>>> drivers/platform/x86/ alone + the native gpu backlight drivers. So
>>> what we really need is a solution for any laptop not using
>>> acpi-video for backlight control and not running one of the big 4
>>> desktop environments.
>>>
>>> Note that we pretty much have the same problem for any acpi event,
>>> power button pressed, lid closed, etc. are all "key press" type
>>> events typically handles by the desktop enviroment (e.g. we don't
>>> automatically suspend on lid-close, we just tell userspace). And we
>>> already have a solution for these type of events when running a
>>> desktop environment which handles them, these get handled by acpid.
>>> So to me it seems that
>>
>> s/handles/does not handle/  small but important typo.
>>
>>> the obvious (and one and only right) way to fix this is to teach
>>> acpid to deal with brightness key-presses.
>>>
>>> I'm willing to write a patch for acpid to implement this, and then
>>> Julian's setup should just work without needing any special kernel
>>> commandline options.
>>>
>>> Julian would that be an acceptable solution for you, and would you
>>> be willing to test such a patch ?
> Yes, of course that would be an acceptable solution for me and yes, I
> would be willing to test such a patch.

Ok, great. I've putten this (pretty high) on my todo list, I'll let you
know when I've something ready to test.

Regards,

Hans