[alsa-devel] snd_pcm_avail_update() needed before snd_pcm_delay() with hda-intel
Christian Morales Vega
cmorve69 at yahoo.es
Sat Jun 7 08:25:37 CEST 2008
2008/6/7 Lee Revell:
>> 2- Is snd_pcm_avail_update() really useless when not using mmap?
> The pcm.c example referenced right below that comment would indicate otherwise:
snd_pcm_delay() was added after that example was created?
>> I have a SB Live! where snd_pcm_delay() always returns the correct
>> value, without any need for snd_pcm_avail_update(). But the same code
>> in the same machine with an hda-intel AD1988 needs a call to
>> snd_pcm_avail_update() before snd_pcm_delay() to give the correct
>> result. Without it snd_pcm_delay() always returns the value that *was*
>> correct in the last snd_pcm_writei() call.
>> So should the "application frame position" be always updated, or only
>> in read/write operations? In the first case AD1988 fails, in the
>> second case perhaps SB Live! is making too mucho work ;-)
Rereading this... "application frame position" only is updated in
read/write operations since is the only moment were it changes :-p The
problem would be with the update of the "sound frame position".
> Is this with the latest ALSA HG sources?
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