Re: Context expectations in ALSA

From: Maxime Ripard
Date: Thu Oct 22 2020 - 08:57:48 EST


On Thu, Oct 22, 2020 at 12:03:19PM +0200, Jaroslav Kysela wrote:
> Dne 22. 10. 20 v 11:50 Maxime Ripard napsal(a):
>
> > So, I'm not really sure what I'm supposed to do here. The drivers
> > involved don't appear to be doing anything extraordinary, but the issues
> > lockdep report are definitely valid too. What are the expectations in
> > terms of context from ALSA when running the callbacks, and how can we
> > fix it?
>
> I think that you should set the non-atomic flag and wake up the workqueue or
> so from interrupt handler in this case. Call snd_pcm_period_elapsed() from the
> workqueue not the interrupt handler context.

Yeah, that was my first guess too. However, the DMA driver uses some
kind of generic helpers using a tasklet, so getting rid of it would take
some work and would very likely not be eligible for stable.

Maxime

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