Radeon 9250 Lockup

[Benjamin Herrenschmidt]

On Sun, 2005-10-09 at 23:47 +0100, Edward Chapman wrote:
> Hi,
> 
> Software:
> X.org 6.8.99.900 downloaded from CVS today
> Linux kernel 2.6.13.3, monolithic (don't like modules, root kit risk, etc.)
> LFS built system - gcc 3.4.4, glibc 2.3.5, linux-libc-headers-2.6.11.2
> 
> Hardware:
> Sapphire Radeon 9250 128MB PCI
> ASUS P5WD2 PREMIUM Motherboard (Socket 775, Intel 955x Chipset)
> Pentium D 840 Dual Core CPU
> 2GB Crucial RAM
> 
> X works great, no errors in /var/log/Xorg.0.log.  Except when I start a
> backup to my DAT tape drive (/dev/nst0) connected to an Adaptec SCSI PCI
> controller, after about 30 seconds the whole system freezes, can't even
> ping it anymore.  No option but a hard reset.
> 
> With X.org 6.8.2 instead of freezing the box, only X froze.  On SSHing
> into the machine X process was consuming 99% CPU and /var/log/Xorg.0.log
> filling up with
> 
> (EE) RADEON(0): GetBuffer timed out, resetting engine...

.../...

Smells like the radeon is getting too many retries on the PCI due to the
bus beeing saturated and the engine is timing out or something like
that... Maybe something in the radeon isn't handling losing arbitration
or not getting it in time gracefully. It may be interesting to try
tweaking some of the PCI related settings in there in BUS_CNTL

Ben.