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    SubjectRe: LibPATA code issues / 2.6.17.3 (What is the next step?)
    Mark Lord wrote:
    > Justin Piszcz wrote:
    >> They are Western Digital 400* drives.
    >>
    >> [4294678.049000] Vendor: ATA Model: WDC WD4000KD-00N Rev: 01.0
    >> [4294678.050000] Vendor: ATA Model: WDC WD4000KD-00N Rev: 01.0
    >>
    >> On a SiL controller, it also happens when they are on a promise
    >> controller too.
    >>
    >> On Fri, 14 Jul 2006, Mark Lord wrote:
    >>
    >>> Justin Piszcz wrote:
    >>>>
    >>>> opcode=0x35 & opcode=0xca
    >>>
    >>> Those are non-DMA WRITE opcodes. Using PIO for I/O is pretty rare
    >>> these days,
    >>> so I'm betting that this is not a hard disk device -- compactflash?
    >
    > Okay. So why are we issuing PIO WRITE commands to drives that
    > obviously should only be sent DMA commands by libata?
    >
    > Perhaps that's the bug.

    Oh wait.. I remember this.. No, those are DMA commands,
    despite the misleading libata name for them. We went through
    this before last spring..

    Okay. So I wonder what's really going on.
    The next step would be to instrument the interrupt handler,
    so that when it sees bad-status, it dumps out the stat/err values
    right then and there, before anything else can muck with them.

    It might also be good to have it dump out the controller engine's
    DMA status/err values, assuming the controller has registers for those.

    Then we should get a better picture of what's going on.
    Assuming the drives aren't lying to us (a perfectly good assumption here),
    then the controller must be aborting the transfer unexpectedly.

    Cheers
    -
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