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    SubjectRe: Kernel Summit request for Discussion of future of ATA (libata) and IDE
    > I guess that bit doesn't really make any difference with remotely modern 
    > drives, then.. Could we make that ata_id_has_dword_io check always
    > return true if ata_id_is_ata returns true and only check word 48 if not?

    I suspect (but need to dig further) that ata_id_has_dword_io should only
    be called by pata_legacy.

    > I saw Willy Tarreau's patch from February for this, I agree that we
    > should likely use a separate data_xfer method for 32-bit transfer (or if
    > enough controllers should support 32-bit, then just make it be the
    > default and make a separate 16-bit only function for those that don't),
    > rather than punting the decision to the user with hdparm.

    Definitely.

    > You mentioned in the thread for Willy's patch that "some
    > controllers have quirky rules for 32bit xfers" - any details anywhere?

    There are two main ones

    - Some controllers only support 32bit I/O for a multiple of 32bit values
    [sometimes 'unless the fifo is disabled']. I'd have to go back over the
    docs but I think the AMD may be one of those
    - Some controllers (VLB generally) require a magic sequence before the
    transfer. You'll see that in the pata_legacy bits.

    Alan


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