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    SubjectRe: ide-cd problem
    Alan Chandler wrote:
    > On Tuesday 23 November 2004 21:49, Alan Chandler wrote:
    >
    >
    >>Before, I thought my hardware was a little out of spec - now I think there
    >>is something else at play here.
    >>
    >
    >
    > Firstly, I think there might be another race condition like the one Alan Cox
    > found. I attach a patch below with the fix for that (against 2.6.10-rc2, an
    > including Alan's patch) I'm not 100% sure its necessary, but it seems fix a
    > variation I have been seeing.
    >
    > With it in place, and apart from the ongoing issue - see below, I have managed
    > to remove the delay in drive_is_ready() altogether without any ill effects.
    >
    > [my reading of the ATA spec is that 400ns is needed after reading the status
    > reg before IRQ is removed, I had wondered whether it would be better to
    > record the time here and then check whether we had used up the 400ns just
    > before returning from the interrupt state]

    The method is sound, I did some industrial control in a previous job and
    used a back-to-back timer in a similar way. Just before starting an
    operation I checked to see that it wasn't too soon and did a delay if so.

    Depending on the path through the code, it may be easier to get right by
    just putting in the delay.

    --
    -bill davidsen (davidsen@tmr.com)
    "The secret to procrastination is to put things off until the
    last possible moment - but no longer" -me

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