[alsa-devel] snd_pcm_avail_update() needed before snd_pcm_delay() with hda-intel

[Christian Morales Vega]

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?
openSUSE Build Service multimedia:audio packages:
- alsa-1.0.16.hg20080510
- libasound2-1.0.16.hg20080510
- alsa-driver-kmp-default-1.0.16.20080606_2.6.22.17_0.1