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    SubjectRe: [PATCH] 2.5.15 IDE 61
    Uz.ytkownik Neil Conway napisa?:
    > Martin Dalecki wrote:
    >
    >>There is no problem to go in paralell on different channels for
    >>requests. The serialization has only to be done
    >>for the drive setup.
    >
    >
    > I agree for general chipsets, but my whole point was with regard to
    > buggy chipsets which need to be serialized on both channels.
    >
    > If you're saying that even these broken chipsets are OK with having
    > transfers on one channel while setting up transfers on another channel,
    > then perhaps you are right but that's not what I believed to be the case
    > (can't find info to tell me either way right now).
    >
    > But if that really were the case, then how could the (e.g.) cmd640
    > problem ever have been manifested? A spinlock is ALWAYS held while
    > ide_do_request is executing. Even if it weren't, only an SMP machine
    > could be trying to program both channels simultaneously because
    > interrupts are disabled too.


    Well in the next patch round the hwgroup will be replaced with
    a spin lock, which is supposed to be shared between channels which need
    forced access serialization between them. Please look
    at patches 62a and 63 :-).


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