Mark Lord wrote:
Chip errata sometimes prevents reliable use of PIO commands which involve more than a single DRQ (data request). In normal operation, libata should not generate such PIO commands (uses DMA instead), but they could be sent in via SG_IO from userspace. A full workaround might be to break up such commands into sequences of single DRQ ones, but that's just way too complex for something that doesn't normally happen in real life. So, allow the attempt (it often works, despite the errata), but log the event for reference when somebody screams. Signed-off-by: Mark Lord <mlord@xxxxxxxxx>
applied patches 1-2
Tejun/Alan/Jeff: We may also want a patch to prevent libata-eh from downshifting all the way to PIO on these chipsets, but I am not sure how to accomplish that from inside sata_mv. Any suggestions?
Do we really want that? Seems to me we need that for older bridged PATA devices attached to a SATA bridge.
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