[Intel-gfx] [PATCH v2] ALSA: hda/i915 - avoid hung task timeout in i915 wait

[Kai Vehmanen]

Hi,

On Wed, 9 Mar 2022, Takashi Iwai wrote:

>> Takashi Iwai wrote:
>>> The question is how often this problem hits.  Basically it's a very
>>> corner case, and I even think we may leave as is; that's a matter of
>>> configuration, and lowering such a bar should expect some
>>> side-effect. OTOH, if the problem happens in many cases, it's
>>> beneficial to fix in the core part, indeed.

I'm basicly helping out the intel-gfx folks here. This is now happening 
systematically in the intel-gfx CI. The hung-task timeout is configured to 
30sec (in intel-gfx CI), and there's some new hw configs where this 
happens every time (I have a separate patch in progress [1] that tries 
to detect this case and skip the init, but this will require more time as there is 
risk of breaking existing configurations).

[1] 
https://lists.freedesktop.org/archives/intel-gfx-trybot/2022-February/128278.html

Tvrtko Ursulin wrote:
> Takashi Iwai wrote:
> > Complete behaviour change how? Isn't this something ran on probe so
> > likelihood of anyone sending SIGKILL to the modprobe process is only
> > the init process? And in that case what is the fundamental difference
>
[...]
> The point is that it does change the actual behavior, and changing the
> actual behavior just for working around the corner case like the above
> wouldn't be justified without the proper evaluation.
> 
> That said, if this behavior change is intentional and even desired,
> that's a way to go.

Let me try this out and test on a few configs (with and without the 
timeout occurring) and send a V3 if this seems ok.

Br, Kai