Alan Cox wrote:
The limit for sata_mv chipsets seems to actually be 7-sectors or less
for read/write multiple. Which means a max of 4 in practice.
Similarly, we should also be preventing *any* PIO of more than one DRQ
for sata_mv. But I don't see a sensible way to do that either.
Ugghhh..
Our infrastructure just flat doesn't deal well with per-xfer-mode sector
count limitations. It is quite easy for us to limit per-xfer sector
count on a __per device__ basis -- both SCSI and block layer handle that
well.
But deviating from that implies potentially having to re-merge (or
split) block layer requests -- IOW quickly moves into the non-trivial,
cross-stack category of problem.
Problem is, of course, sector count limits in ATA can be per-command (or
per-xfer-mode), not just per-device.
Jeff
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