[alsa-devel] position_fix issue / snd-hda-intel / alsa <-> jack
tiwai at suse.de
Tue Feb 12 11:34:02 CET 2008
At Mon, 11 Feb 2008 22:22:27 +0100,
Wolfgang Woehl wrote:
> I'm sorry I just kind of cc-dumped this in here without any why's and
> how's. It's the sum-up of a communication on jack-devel that left us
> irritated because our devices would perform so strangely.
> Could someone confirm this or hint me towards anything?
Usually position_fix=0 (is almost equivalent with position_fix=2)
should work. But this seems not working on some loose hardwares.
JACK does nothing special but do a very basic full-duplex operation.
The difference is that you use short period size and likely two
periods. So, the position calculation isn't accurate on your
hardware. Maybe the positions of playback and capture streams
differe. An often used workaround for this kind of problems is to
use three periods instead.
(BTW, this problem really depends on the hardware. That's why there
are such a strange module option. So, don't argue this as if it's a
> Thanks, Wolfgang
> Donnerstag, 7. Februar 2008 Wolfgang Woehl:
> > For, at least, our two snd-hda-intel devices (ALC888 and 82801I
> > (ICH9 Family)) both position_fix values (POSBUF and FIFO, 0 and 3
> > respectively) produce ok sound, only that
> > position_fix=0 makes alsa fine and jack crackle/sizzle
> > position_fix=3 makes alsa crackle/sizzle and jack fine
> > "alsa" meaning direct use of alsa and "jack" meaning (at least in
> > my case) jack with the alsa backend.
> > Here I have alsa-1.0.14-31.2 and jack-0.109.2-0.pm.1 (0.pm.1 stems
> > from the packman repository, I guess)
> > Wolfgang
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