CONFIG_DEBUG_KERNEL=y
CONFIG_DEBUG_SLAB=y
CONFIG_MAGIC_SYSRQ=y
CONFIG_FRAME_POINTER=y
kernel, sysrq, and frame_pointer were already enabled. I'll enable debug_slab, as well.
booting with "nosmp acpi=off" did not help. The box hung as before, at
Could you boot with pci=noacpi and report again? The difference is that ACPI will still be used but not for IRQ routing. I have a few boxes out with 2.4.x kernels and Adaptec HBAs that need this to work reliably.
Are you interested in results from "pci=noacpi" by itself or in conjunction with nosmp?
What's the SCSI BIOS version?
The SCSI controller is an onboard AIC 7899 (in a Dell PowerEdge 2650), and reports itself as "25309".
If you find time, send me your BIOS settings and your .config in private email. I didn't track this thread from the beginning, so I don't know if you've already done this.
<http://hashbrown.cts.ucla.edu/pub/oops-200512/> has the .config, lspci -v, and /proc/interrupts for 2.6.14.4 and 2.4.32.