Re: [PATCH] usb audio.

From: Erik Mouw (J.A.K.Mouw@ITS.TUDelft.NL)
Date: Sun Oct 15 2000 - 14:00:42 EST

On Fri, Oct 13, 2000 at 09:16:36PM +0200, Erik Mouw wrote:
> On Fri, Oct 13, 2000 at 10:27:05AM -0700, Dunlap, Randy wrote:
> > How about trying latency_timer=10, which will apparently
> > show up as being 0 (since 10 is smaller than its
> > implemented granularity).
> That didn't help, but I found the problem: APM. I had GNOME battery_applet
> running, and that checks /proc/apm every 2 seconds (default value).
> Removing the applet from the taskbar solved the problem, and as soon as
> I do "cat /proc/apm" the audio stops for about a second.
> I recompiled the kernel with CONFIG_APM_ALLOW_INTS enabled, in the hope
> that the USB interrupts would still come through, but that didn't solve
> it.
> I'm glad I finally found the problem, but how to solve it? Is this a
> bug in APM or in USB?

Seems to be a bug in the APM BIOS implementation of my laptop (Asus
P6300, PII/233, 80MB, Intel 440BX/ZX). I just tried the USB audio
driver on a desktop (AMD K6 3D/333, 160MB, Asus P5A, Ali 1541) and got
none of the hickups. Time to try a BIOS upgrade on the laptop...


J.A.K. (Erik) Mouw, Information and Communication Theory Group, Department
of Electrical Engineering, Faculty of Information Technology and Systems,
Delft University of Technology, PO BOX 5031,  2600 GA Delft, The Netherlands
Phone: +31-15-2783635  Fax: +31-15-2781843  Email:
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