>>Okay, I had to watch for it a bit longer and it turns out that the kernel PDC driver has a problem in this shared interrupt setup. When loads get high it seems to run into some timing problem which causes things like:
>>
>>Feb 4 01:02:22 admin kernel: hde: dma_intr: status=0xd0 { Busy }
>>
>>
>>
Since the busy bit is set, we know the drive must have received a
command. Since dma_intr thought the drive was not busy, an interrupt
must have snuck through between the command being issued and the dma
being started. I think in my original patch, I had the dma start
outside of the spinlock, that is a bug. The command to the controller
to start the dma must be inside of the spinlock.
I have not looked at 2.4.21-pre4 at all, so I could be entirely off base
here.
Ross
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/