[linux-audio-user] IRQ conflicts, acpi, and linux audio

Florian Schmidt mista.tapas at gmx.net
Sat Nov 19 20:44:02 EST 2005

On Sat, 19 Nov 2005 19:18:13 -0500
Lee Revell <rlrevell at joe-job.com> wrote:

> On Sat, 2005-11-19 at 15:19 -0800, thewade wrote:
> > Hello pd and lau lists,
> > 
> > I am having trouble figuring out how to actually change the irq's of specific devices.
> You are wasting your time.  Those IRQ settings are hard wired.  Even if
> this was possible there's no point - there's no meaningful relationship
> between which IRQ your device is on and the performance.

I beg to differ. Especially with RT setups, it can make very much sense
when the audio device does have an irq for itself. On a -rt system this
opens the possibility of raising the soundcard's irq handler priority to
a value higher than the prios of all other irq handlers (i.e. 90). Also
rising i.e. jackd's prio higher (70) than the other irq handlers (around
50) will give rocksolid performance. Compiling a kernel while jack is
running? No problem. Heavy network load? No problem. This would not work
quite as nice with several devices sharing the soundcard irq.

I wonder how non -rt systems (or not properly setup -rt systems) hold up
to loads like this..

Have fun,

Palimm Palimm!

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