md raid0 locks up with IO-APIC

Edward Welbon (welbon@bga.com)
Tue, 3 Feb 1998 09:57:06 -0600 (CST)

My md raid0 locks up hard with symmetric I/O. I am gussing that the
problem is in md or the scsi driver since the lock up occurs in a variety
instances (like building a kernel) when there is a burst of disk activity
(Bonnie locks it up immeadiately). After the lockup, e2fsck won't run
(locks up) and I have to boot to a non IO-APIC kernel to clean up. My HW
has been very reliable for the majority of the 2.1.X series kernels.

The hw details are SuperMicro P6DOF (82450GX) mobo, AMI bios (1.1 SMP
spec), two 200Mhz P6, 128M ram, three ncr53c875 controllers each with
three 2GB IBM DORS drives, one AHA1542CF controller with 1 GB DOR (boot
device), 3c515 (ISA 100bT ethernet).

I apparently have to supply a PIRQ= kernel option to get interrupt
distribution across CPUs if in the bios I assign an IRQ for any PCI slot.
If I allow the bios to associate the PCI INT's to IRQ's, then a PIRQ line
is not needed (I apparently must assign IRQ's to ISA to insure that there
are no PCI/ISA conflicts). Another odd thing is that if I do not assign
IRQ 15 explicitly to ISA the AHA1542CF card fails to show up in the bios
scan (the 1542 is on IRQ 11). I also get the complaint that "pin 0 is not
connected". I assume that these are related.

Ed Welbon - welbon@bga.com