Re: [Openvortex-dev] Low volume, distortion, etc

[Ryan Underwood]

On Sat, Jun 14, 2003 at 05:10:32PM -0400, J. Gordon Wolfe wrote:
> > I did exactly this, several times - there are no differences in playback
> > on my system (Aureal SQ2500).
> > 
> > I'm not experiencing any clicks during playback, but I do experience
> > shifts in stereo. It's as if the channels spontaneously reverse
> > sometimes. this behaviour is (vaguely) linked to the system's load. For
> > example, it happens a lot more in mplayer than in xmms. switching
> > between OSS or alsa output has no effect on the problem.
> > 
> > Does anybody else have this problem?
> 
> Oh thank god its not just me!  That problem's been driving me absolutely
> crazy!    I have a sq2500 too, btw.  I'm just starting to dig into the driver
> code and try and figure out whats going on, but its pretty slow going as I'm
> not really a driver developer.  As you said, the problem is sort of related to
> system load, though I wouldn't say that it will always swap under load or that
> it will only swap under load.  My feeling is its got to have something to do
> with buffer underruns, though I haven't figured out a good way to test that
> hypothesis yet.  I suspect something is done differently after a underrun
> versus when a substream is started, and that makes the difference.  I say this
> because when the channels reverse, if I pause and then unpause XMMS the
> channels unswap (based on dmesg, I think pause stops the substream and unpause
> restarts it.  There are pause and resume substream functions in the code, but
> I don't know what if anything uses them).  If anybody with more knowledge
> would care to comment on this problem and/or possible solutions, I'd
> appreciate it!

I also have an SQ2500 and have experienced the exact same symptoms
dating back to the original aureal driver.  There must be something
peculiar about the SQ2500 in particular, because the people with plain
au8830 cards never complain about this problem.