[alsa-devel] intel 8x0 ALSA driver in virtualbox - choppy sound

[Takashi Iwai]

At Fri, 13 Aug 2010 17:19:10 +0200 (CEST),
Jaroslav Kysela wrote:
> 
> On Fri, 13 Aug 2010, Lex F wrote:
> 
> > Dear all
> >
> > I am having problems with getting sound running well in Arch Linux
> > guest (VirtualBox 3.2.8), the host is OS X Snow Leopard. The problem
> > is that the sound is very choppy. I've checked around VirtualBox and
> > Arch forums and it seems that some others experience these problems as
> > well yet I could not see anyone sufficiently skilled to debug this
> > paying attention. I think there is a problem with either VirtualBox
> > implementation of the sound card or a bug in ALSA driver for that card
> > because I have sound running just fine in VMWare Fusion (using es1371
> > (?) driver), so the host system definitely is fast enough for decent
> > sound quality.

We have had many problems with VMware, too :)
Which sound backend are you using?  Direct ALSA / dmix or PA?

> > I would like to offer my help with identifying the cause of the
> > problem and testing solutions if the need be.
> >
> > I've attached my alsa-info output for your reference. Please let me
> > know if there is anything else I could try to help.
> >
> > I am very keen to help but I don't know how.
> 
> http://www.alsa-project.org/main/index.php/XRUN_Debug is a good start to 
> see if the virtual machine does receive interrupts in the right time.

Actually, there is no real interrupt, but just the virtual one,
thus it can be never accurate.  So, rather the question is how the
driver is tolerant for sloppy IRQ updates.

Usually, when the period size is large and the buffer have many
periods (not two), the delayed update works more stably.


Takashi