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List:       linux-audio-dev
Subject:    Re: [linux-audio-dev] (not so low) low latency - acpi, dri, proc
From:       Fernando Pablo Lopez-Lezcano <nando () ccrma ! Stanford ! EDU>
Date:       2002-08-26 18:34:32
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> > I suspect acpi might be the culprit but I cannot try to
> > disable it because on this particular laptop you need acpi to
> > make sound work (probably something to do with routing of
> > interrupts,, also tried pci=biosirq on a non-acpi kernel
> > without success). Any suggestions?
>
> Hmmh, are you confusing ACPI and APIC here?
>
> ACPI is about power saving and APIC is about routing interrupts, etc...

I'm talking about the power saving subsystem. A kernel without
the latest sourceforge acpi patch boots, but the routing of
interrupts (and maybe something else?) is broken and sound
does not work at all. With the acpi patch sound works fine,
except for the 170mSec spikes I see when running latencytest.
Obviously I cannot remove acpi to see if that is actually the
problem :-)

> > Proc: something has changed from the 2.4.18 to the 2.4.19
> > kernels (maybe the acpi proc interface is to blame?). Big
> > mess of latency spikes in the proc latency test.
>
> No problems here with 2.4.19-jl series... Steady at 0.9 ms when using 128
> byte buffers with ENS1371.

Sigh... :-)
-- Fernando
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