[alsa-devel] snd_dummy on Centos - Redhat

Takashi Iwai tiwai at suse.de
Thu Sep 3 16:18:15 CEST 2009

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
  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:

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



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