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...

Erik

-- 
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: J.A.K.Mouw@its.tudelft.nl
WWW: http://www-ict.its.tudelft.nl/~erik/
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