[PATCH] drm/radeon: add new AMD ACPI header and update relevant code

[Alex Deucher]

On Thu, Jul 26, 2012 at 3:42 PM, Alex Deucher <alexdeucher at gmail.com> wrote:
> On Thu, Jul 26, 2012 at 3:33 PM, Luca Tettamanti <kronos.it at gmail.com> wrote:
>> On Thu, Jul 26, 2012 at 11:35:25AM -0400, Alex Deucher wrote:
>>> On Thu, Jul 26, 2012 at 8:58 AM, Luca Tettamanti <kronos.it at gmail.com> wrote:
>>> > The other missing bit is how to actually change the brightness... Alex,
>>> > do you know what registers to poke?
>>>
>>> You need to check if the GPU controls the backlight or the system
>>> does.  I think the attached patches should point you in the right
>>> direction.
>>
>> Yep :)
>>
>> 0050:  ATOM_FIRMWARE_CAPABILITY_ACCESS usFirmwareCapability :
>>   0050:  (union) ATOM_FIRMWARE_CAPABILITY sbfAccess          :
>>     USHORT GPUControlsBL:1                              = 0x0001     (1)
>>
>> The panel is using the INTERNAL_UNIPHY encoder, and I see the
>> UNIPHYTransmitterControl command table.
>>
>> Interaction with video.ko is still a bit messy...
>>
>> Do you already have code for handling the notifications? I'll work on it
>> in the weekend otherwise ;)
>
> I don't have patches for that.  Please feel free to work on it :)

One thing worth checking, the sbios may write the requested backlight
level to the bios scratch reg, in which case the driver only has to
execute the BL_BRIGHTNESS action rather than writing the requested
level to the register first.

Alex

>
> Thanks,
>
> Alex