[linux-audio-user] latency questions

G. M. Bodnar greg at sapheron.org
Tue Oct 15 18:53:01 EDT 2002


I was running through the low-latency howto and I ran into a couple
things that seem to be hindering process.

First off, I'll mention that I'm using a Dell Inspiron 2650 laptop.
I'm running debian unstable with 2.4.19.

1) DMA transer won't enable.  I've enabled DMA transfers in the kernel
as suggested by the howto.  However, I'm unable to turn on dma access
with hdparm.  I'm told the operation is not permitted.

2) IRQ mess.  dmesg lists that almost every device that is detected is
on irq 10, including the onboard sound (i8x0) and video card (nVidia).
As a result, in X, I get static and pops as the audio is delayed.
Searching further, I noticed a message saying the APIC wasn't being used
due to a buggy bios provided by Dell.  This could explain why everything
is pushed to IRQ 10.

Has anyone had these problems, and more importantly, gotten around them?
I'm not sure if the bios problem mentioned is accurate for the 2650.
Looking through the kernel source, it clumps a bunch of models together.
I'm tempted to hack through that and see if it does crash...

Thanks

Greg
--- -



More information about the Linux-audio-user mailing list