[alsa-devel] [V2 2/2] vgaswitchreoo: set audio client id in vgaswitchreoo enable function

[jimqu]

在 2018/7/16 22:16, Lukas Wunner 写道:
> On Mon, Jul 16, 2018 at 03:52:45PM +0800, Hui Wang wrote:
>> On 2018???07???16??? 14:06, Jim Qu wrote:
>>> On modern laptop, there are more and more platforms
>>> have two GPUs, and each of them maybe have audio codec
>>> for HDMP/DP output. For some dGPU which is no output,
>>> audio codec usually is disabled.
>>>
>>> In currect HDA audio driver, it will set all codec as
>>> VGA_SWITCHEROO_DIS, the audio which is binded to UMA
>>> will be suspended if user use debugfs to control power
>>>
>>> In HDA driver side, it is difficult to know which GPU
>>> the audio has bound to. So set the bound gpu pci dev
>>> to vgaswitchreoo, the correct audio id will be set in
>>> vgaswitchreoo enable function.
>>>
>>> Signed-off-by: Jim Qu <Jim.Qu at amd.com>
>> Is it possible to send this patch to <stable at vger.kernel.org> as well, then
>> we will know that it is safe to backport this patch to the linux kernels
>> with different version.
> For which hardware do you want it in stable kernels?
>
> This patch pertains to manual power control, which is only used on the
> MacBook Pro by default.  And there are no MacBook Pros with AMD APUs.
> On all other hardware, users have to specify "amdgpu.runpm=0" on the
> command line to see any benefit from this patch.  Also, manual power
> control will likely be removed once we get runtime PM working with
> muxed systems (such as the MacBook Pro).

The patch idea will deal with the issues 1) manual power control after 
v4.17. 2) driver control before v4.17.  As we know current a lot of 
mainstream OS, such like ubuntu 16.04.4 (kernel is v4.15), ubuntu 
18.04(kernel is v4.15), RHEL7.x (kernel is 3.1x).
BTW, I believe you will see more and more products with AMD next 
generation of APUs in the near future.

Thanks
JimQu

> Lukas

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