[linux-audio-user] Ardour, Jack, and 2.6 kernels + XRuns with the Audiophile 24/96 M-Audio

[John Anderson]

On Tue, 2004-06-01 at 08:14, Malcolm Baldridge wrote:
> > So, am I completely hosed with my Adaptec SCSI drive setup?  Anybody 
> > have any insight into these Adaptec controllers?  I've fussed with the 
> > setpci latency_timer settings (from Jan Depner's "Installing and 
> > configuring ALSA, JACK, & Ardour..." web site), but still see long 
> > xruns.  

> If you could email the output from lspci -v and procinfo, that would be great.
> 
> Also, which exact kernel setup are you using?  Preemptible? 
> Preempt+low-latency?  Con Kolivas' "LCK1" patches which combine O(1)
> scheduler, and two sets of low-latency patches, including patches to the I/O
> subsystem?
> 
> Also, which filesystems are you using for your audio data drive?  If you're
> using ext3, which journalling mode?  data=writeback seems to provide alot
> better latency than the default data=ordered.  Reiserfs seems to solve alot
> of problems as well, if you're willing to reformat your audio drive.  It's
> easier to change your ext3 journalling mode (no reformat is necessary).
> 
> What kind of SCSI drives are you using?

I had these problems as well. There's a long thread a few months back
where it was confirmed that I tried *everything*. Eventually I gave up
and bought an IDE drive. Hey presto, problems gone. Now the only xruns
happen when there's scsi disk activity, according to vmstat.

The only time I didn't have these problems was with a MSI dual-athlon
board that had a 64-bit PCI slot where the 29160 was plugged in. I only
realised later (after the motherboard was on a ship to Taiwan, for a
different reason) that the 64-bit slot was on a separate bus from the
32-bit slot where the audio card (Terratec EWS88MT) was plugged in. That
board didn't give me xruns either. I think that's a plausible
explanation, but then again it may have been because there were 2 cpus.

On the other hand, I can't help wondering if the bus-greediness of the
Adaptec controllers isn't a driver issue. I had a brief look at the
driver sources, but I don't know enough about kernels and drivers to
have made sense of them.

bye
John