Russell King writes:
> Alan Cox writes:
> > One possible thing to try on the debugging side is at the 'official'
> > end of the DMA turn off the master bit for the IDE controller, do an
> > arbitary pci read (to flush anything pending) then do a check
>
> When a buffer is on the free list, I assume that the b_blocknr and b_dev_id
> elements are never used? I'd like to use these to make "notes" into the bh
> struct about where the bh was placed onto the queue from. (I'll probably
> have tried it before anyone gets around to replying...)
Ok, well the b_dev_id appears to be unset by any of my code when it goes
wrong, so I'm not sure where this bh is coming from. (and I'm starting
to get pissed about this problem).
It is not limited to BM-DMA. I can reproduce the exact same crashes by
doing repeated hdparm -t /dev/hda with the drive in PIO mode.
That means that there are zero active PCI bus masters on the bus. What
next? I dunno, but there definitely seems to be some problem there.
_____
|_____| ------------------------------------------------- ---+---+-
| | Russell King rmk@arm.linux.org.uk --- ---
| | | | http://www.arm.linux.org.uk/~rmk/aboutme.html / / |
| +-+-+ --- -+-
/ | THE developer of ARM Linux |+| /|\
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