Re: Bug Report - [Acer Aspire V5-122P] Unable to adjust screen brightness

[Aaron Lu <aaron.lu@intel.com>]

On 05/26/2014 04:42 AM, Lewis Toohey wrote:
> On 23 May 2014 13:50, Hans de Goede <hdegoede@redhat.com> wrote:
>> Hi Lewis et all,
>>
>> On 05/23/2014 02:07 PM, Lewis Toohey wrote:
>>> On 23 May 2014 02:34, Aaron Lu <aaron.lu@intel.com> wrote:
>>>> On 05/21/2014 09:02 PM, Lewis Toohey wrote:
>>>>> Hi Aaron
>>>>>
>>>>> I followed your instructions and can report some limited success. I
>>>>> have two interfaces listed in /sys/class/backlight namely:
>>>>>   acpi_video0  radeon_bl0
>>>>>
>>>>> max_brightness for acpi_video0 is 11. Echo-ing new values to
>>>>> brightness appears to have no effect.
>>>>>
>>>>> max_brightness for radeon_bl0 is 255. Echo-ing new values to
>>>>> brightness does adjust the screen brightness as you would expect.
>>>>>
>>>>> Results are the same on both battery and powered.
>>>>>
>>>>> I hope that is useful.
>>>>
>>>> I think Hans' patchset should solve your problem, can you please give it
>>>> a try? You will need to pass the video.use_native_backlight=1 to kernel
>>>> cmdline when testing, thanks.
>>>>
>>>> [PATCH resend 0/4] Make video.use_native_backlight=1 work properly with nouveau
>>>> http://www.spinics.net/lists/dri-devel/msg59941.html
>>>>
>>>> -Aaron
>>>
>>> Aaron
>>>
>>> Thank you for this. Unfortunately I am going to have to ask you for a
>>> bit of help here as I am now, officially, "out of my depth". I
>>> appreciate this is a pain as you will have to take time explaining it
>>> to me and I apologise for that.
>>>
>>> I have figured out how to pass the kernel command line argument, this
>>> is not an issue.
>>>
>>> I have located the patch you refer to here:
>>> https://bugzilla.redhat.com/attachment.cgi?id=894577
>>> (which I believe is correct) but I cannot figure out how to apply it.
>>
>> That is not the right patch, you need a set of 2 patches. I've attached
>> them to this mail. Note please ignore the numbering starting at 6, these
>> are the 2 patches you need. You will need to build a Linux kernel with
>> these 2 patches applied, see your distributions documentation on how
>> to build a kernel from source.
>>
>> I don't know which distro you are using, I've a Fedora kernel with this
>> patches included available here:
>>
>> http://people.fedoraproject.org/~jwrdegoede/rhbz1093171/
>>
>> Regards,
>>
>> Hans
> 
> Hans
> 
> Unfortunately I am unable to apply these patches against the latest
> mainline kernel. I get two fails when applying the second patch file
> and then the kernel will not compile. Please see output information
> below.

I've prepared a git branch for you:
https://github.com/aaronlu/linux.git for-lewis

It's based on Rafael's linux-next plus Hans' patch 2 and 3.

Thanks,
Aaron

> 
> Can you advise?
> 
> Many thanks
> 
> ===APPLYING PATCHES TO LATEST MAINLINE KERNEL====
> 
> lewis@HappyFunMeaowMeaow:~/KernelTesting/Kernel/linux$ patch -p1 <
> 0006-backlight-Add-backlight-device-un-registration-notif.patch
> (Stripping trailing CRs from patch; use --binary to disable.)
> patching file drivers/video/backlight/backlight.c
> (Stripping trailing CRs from patch; use --binary to disable.)
> patching file include/linux/backlight.h
> lewis@HappyFunMeaowMeaow:~/KernelTesting/Kernel/linux$ patch -p1 <
> 0007-acpi-video-Unregister-the-backlight-device-if-a-raw-.patch
> (Stripping trailing CRs from patch; use --binary to disable.)
> patching file drivers/acpi/video.c
> Hunk #1 FAILED at 151.
> Hunk #2 succeeded at 161 (offset -1 lines).
> Hunk #3 FAILED at 1837.
> Hunk #4 succeeded at 1868 (offset -113 lines).
> Hunk #5 succeeded at 1999 (offset -113 lines).
> Hunk #6 succeeded at 2023 (offset -113 lines).
> 2 out of 6 hunks FAILED -- saving rejects to file drivers/acpi/video.c.rej
> 
> 
> ==LAST LINES OF BUILD BEFORE FAIL===
> 
>   CC [M]  fs/xfs/xfs_ioctl32.o
>   LD [M]  fs/xfs/xfs.o
> make[1]: Leaving directory `/home/lewis/KernelTesting/Kernel/linux'
> make: *** [debian/stamp/build/kernel] Error 2
> lewis@HappyFunMeaowMeaow:~/KernelTesting/Kernel/linux$
> 
>