Re: [linux-audio-dev] Re: [announce] [patch] Voluntary Kernel Preemption Patch

Ingo Molnar
2004-07-21T05:38:33Z

* Andrew Morton <akpm@osdl.org> wrote:

> > discovered I can reliably produce a large XRUN by toggling Caps Lock,
> > Scroll Lock, or Num Lock. This is with 2.6.8-rc1-mm1 + voluntary
> > preempt
>
> That's odd. I wonder if the hardware is sick. What is the duration is the
> underrun? The info you sent didn't include that.

no, it's the ps2 driver that is sick. The ps2 keyboard driver is one of
the few places that busy-polls for IRQ completion from within a tasklet
context for things like led switching (yuck) - this can cause many
millisecs delays on all boards i tried.

Ingo