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    SubjectRe: Linux 2.5.3-pre1-aia1
    On Mon, Jan 21, 2002 at 03:22:20AM -0800, Andre Hedrick wrote:
    > On Mon, 21 Jan 2002, Vojtech Pavlik wrote:
    >
    > > On Sun, Jan 20, 2002 at 04:12:36PM -0800, Andre Hedrick wrote:
    > >
    > > > > > > We only read out 4k thus the device has the the next 4k we may be wanting
    > > > > > > ready. Look at it as a dirty prefetch, but eventally the drive is going
    > > > > > > to want to go south, thus [lost interrupt]
    > > > > >
    > > > > > Even if the drive is programmed for 16 sectors in multi mode, it still
    > > > > > must honor lower transfer sizes. The fix I did was not to limit this,
    > > > > > but rather to only setup transfers for the amount of sectors in the
    > > > > > first chunk. This is indeed necessary now that we do not have a copy of
    > > > > > the request to fool around with.
    > > >
    > > > Listen and for just a second okay.
    > > >
    > > > Since the set multimode command is similar to the set transfer rate, if
    > > > you program the drive to run at U100 but the host can feed only U33 you
    > > > have problems. Much of this simple arguement is the same answer for
    > > > multimode.
    > > >
    > > > Same thing here but a variation, of the operations,
    > >
    > > So you're saying that if you program the drive to multimode 16, you
    > > can't read a single sector and always have to read 16? That not only
    > > doesn't make sense to me, but it also contradicts anything that I've
    > > heard before.
    >
    > Vojtech,
    >
    > If the device is programmed for to do 16 sectors in multimode, it and you
    > issue a read/write multiple pio and short change the device it is not
    > going to like it. However if it is programmed for multimode and you issue
    > single sector pio transfers command opcodes it is fine.
    >
    > Do we differ?

    I think so. Check my mail from 11:14:56 GMT today. I fully understand
    that if I supply less data to the device than it expects or get less
    from it than it has, it'll be a problem. But I think the specification
    doesn't prohibit reading amounts not divisible by multimode setting via
    the multimode command. I've read it quite carefully again.

    --
    Vojtech Pavlik
    SuSE Labs
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