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

[Romain Bossart]

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.
> 
> 
> Thank you for your help!
> 
> Romain