Re: Re: should i be able to abort in the middle ofsnd_pcm_mmap_{begin,commit} ?

[Abramo Bagnara <abramo@alsa-project.org>]

Jaroslav Kysela wrote:
> 
> > > Hmm, the mmap semantics of stop_threshold should be similar to the
> > > read()/write() API.
> >
> > And this was already true. If you use mmap or read/write is irrelevant
> > wrt stream stop in XRUN state.
> 
> Right, but the stream is RUNNING. My change does nothing else than
> checking if an xrun state occured in the user space and synchronizes
> the kernel code with this situation. Definitely the PCM state should be
> XRUN not RUNNING when snd_pcm_avail_update() returns -EPIPE. It was very
> misleading for application to receive these broken results.

I've thought more about this and I'm happy to say that I think you're
right about your patch.

This change a bit the "when" part of xrun detection (previously was
doable only by kernel space), but once documentented I think it's
correct.

I still have doubts about snd_pcm_avail_update return value.

Should it return a value > buffer_size when stop_threshold is high?

Actually snd_pcm_mmap_begin automatically will reduce this amount to
contiguous size...

So yes, I think it's a good work. At the time of the first reading it
looked awful at my eyes, but now I've seen the light.

Sorry for the noise.

-- 
Abramo Bagnara                       mailto:abramo@alsa-project.org

Opera Unica                          Phone: +39.546.656023
Via Emilia Interna, 140
48014 Castel Bolognese (RA) - Italy

ALSA project               http://www.alsa-project.org
It sounds good!

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