[SRU][H/G/OEM-5.10][PATCH 0/1] alsa/hda: the hdmi audio dosn't work on TGL machines

[Hui Wang]

On 3/5/21 4:45 PM, Stefan Bader wrote:
> On 05.03.21 07:06, Hui Wang wrote:
>> BugLink: https://bugs.launchpad.net/bugs/1917829
>>
>> [Impact]
>> On the TGL machines, we plug a dp mst hub to the thunderbolt port,
>> and plug a hdmi/dp monitor to the dp mst hub, then check the
>> gnome-sound-setting, could not find the hdmi/dp audio device.
>>
>> [Fix]
>> backport a patch from upstream, this patch change to assign
>> the pcm slot dynamically on TGL macines.
>>
>> [Test]
>> On 2 lenovo and dell TGL machines, plug dp mst hub and plug
>> 2 monitors to the hub or to the machine hdmi/dp ports, check
>> the gnome-sound-setting, there are 2 hdmi/dp audio devices.
>> and they all could output sound.
>>
>>
>> [Where problems could occur]
>> After this change, the hdmi audio device number starts from 0, 1, ...,
>> while without this change, the hdmi audio device number is fix
>> mapped, it could be 3 or 5 directly. So if there is some userspace
>> applications depends on the fix mapped hdmi audio device, these
>> applicatons could not work on TGL machines.
>>
>> So far, we don't know if those applications exists or not, but I
>> could confirm the ubuntu audio stack builds on the alsa-lib and
>> pulseaudio, this change will not affect the applications based
>> on the alsa-lib and pulseaudio.
>>
>> And I already tested audio functions under ubuntu on the TGL machines,
>> there is no regression.
>>
>>
>> Hui Wang (1):
>>    ALSA: hda/hdmi: let new platforms assign the pcm slot dynamically
>>
>>   sound/pci/hda/patch_hdmi.c | 18 +++++++++++++++++-
>>   1 file changed, 17 insertions(+), 1 deletion(-)
>>
> The bug report claims this as needed on Focal as well, but the 
> submission here does not mention it. What about Focal?

The 5.4 focal kernel can't support TGL platforms, this patch is 
meaningless for focal kernel. So I didn't add F in the submission.  I 
just removed Focal from bug report.

Thanks,

Hui.


>
> -Stefan
>