[alsa-devel] [PATCH] ASoC: Intel: Bsw: Read sst DSP DMA pointer after period elapse occurs

[Mark Brown]

On Tue, Aug 18, 2015 at 05:33:33PM +0000, Fang, Yang A wrote:

> > > We should not read sst hw_ptr and pcm_delay in
> > > sst_platform_pcm_pointer Since it will be ricky if
> > > sst_platform_pcm_pointer is called while dsp is updating the
> > > timestamp.Now read sst hw_ptr after period elapse interrupt occurs.

> > So I guess there's still some risk that we could run into problems here if we
> > take too long to service the interrupt and/or the period is very short?  Is
> > there anything we can do to improve that?

>  I think before and after the patch. There is no difference in term of 
>  handling the period elapse interrupt . because before the patch 
>  sst_period_elapsed calls the snd_pcm_period_elapsed which in turn 
>  calling the sst_platform_pcm_pointer which calls the stream_read_tstamp.

I'm not sure I understand what the patch fixes then?  My concern is that
we're just moving the timing around which changes but doesn't address
the race condition.
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