[alsa-devel] snd_dummy on Centos - Redhat

[Takashi Iwai]

At Thu, 03 Sep 2009 13:50:26 +0200,
Clemens Ladisch wrote:
> 
> (please don't top-post)
> 
> Giovanni Maruzzelli wrote:
> > In centos is 1000HZ, in the kernels I compiled is 100HZ
> 
> I would have expected these to be the other way around, since higher
> timer frequency should result in more accurate simulated sound card
> interrupts.

Actually, it's maybe because of a bad code in snd-dummy driver.
It issues the timer update at each tick.  Thus with more HZ, it can
loose more ticks and be less accurate.

I worked on it ago, and changed the code to update in a better way.
But forgot to apply to the upstream.

Now I digged down, and resurrected it with the highres timer support
as a quick hack.

The patches are found in sound-unstable GIT tree topic/dummy-hrtimer
branch:
  git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-unstable-2.6.git topic/dummy-hrtimer

and in alsa-driver-unstable snapshot as well:
  ftp://ftp.kernel.org/pub/linux/kernel/people/tiwai/snapshot/alsa-driver-unstable-snapshot.tar.gz


Giovanni, give it a try.  If it works, I'm going to add it to 2.6.32.


thanks,

Takashi