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Tejun Heo wrote: > [cc'ing Albert and linux-ide]> > Alan Cox wrote:>> /from the media. */>>> > + if (qc->nbytes < 2048) >>> > + return -EOPNOTSUPP; >>> > + >>> > /* No ATAPI DMA in smart mode */ >>> > if (itdev->smart) >>> > return -EOPNOTSUPP; >>> > >>>>>> This looks like a gross hack. Aren't you supposed to inspect >>> the command instead and whitelist the ones you know are OK, >>> like pata_pdc2027x.c and sata_promise.c do?>> It does seem to be about transfer size in the IT821x case not commands. >> It may be to do with how we issue ATAPI command transfer sizes from high >> up (patch went to Jeff) but for now this is definitely the right approach >>>> Reviewed-by: Alan Cox <alan@redhat.com>> > I wonder whether we should be using similar check in generic path too. > We have quite a few cases where MWDMA ATAPI devices choking on commands > with small transfer sizes. I don't think we'll experience significant > performance regression with this applied and even if there is some, it's > far better to have slightly slower working device.> > What do you guys think? Need to look at, or know, a standard profile of submitted commands. It's quite possible some high performance commands want this, where possible. Jeff - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ | ||||||||||||
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