[LAU] SCSI controller (aic7xxx) and xruns on 2.6 rt9 kernel

[John Anderson]

On Sun, 2007-09-30 at 17:04 +0200, Romain Bossart wrote:
> I forgot to mention that my audio card does not share
> its IRQ with aic7xxx.
> 
> Romain Bossart wrote:
> > Hi,
> > 
> > I have many xruns when I read/write files on my SCSI
> > disks. The suspected module is aic7xxx. I read a thread
> > on LAU ('xrun madness') about this, but it dates back
> > to 2004 and gives no solution. This problem does not
> > occur with my other SATA drives. Could someone give me
> > advices to troubleshoot this?
> > 
> > 
> > Details:
> > 
> > I have an Adaptec 39160 controller and 2 disks
> > in a RAID1 (software) array. The module is aic7xxx.
> > My filesystem is ext3. I use debian/unstable with a 2.6.22
> > RT kernel and RTirq. I tweaked my PCI latencies to 0
> > for the Adaptec PCI bus using setpci.
> > 
> > Jackd being launched RT, I have no xruns with
> > journalling operations or updatedb. But moderately
> > intense operations on this array do cause many many xruns:
> > for instance loading files into memory (launching
> > firefox, or apt-get update, or copying files).
> > Of course, recording music with Ardour causes
> > many xruns too.
> > 
> > Quite surprisingly (for me), I have no xruns when
> > using my other SATA RAID5 (software) array, even
> > very intensively.

I had exactly this trouble with an Adaptec 29160 when I moved from a
dual-processor motherboard to a single-processor (about 4 years ago). I
eventually gave up and bought an IDE drive. I've since moved to a dual
core, with a SATA drive.

bye
John