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"Shaun" == Shaun Tancheff [off-list ref] writes:
Shaun,
Shaun> You are correct in that we can advertise the larger limit in
Shaun> ata_scsi_dev_config() when only SCT write same is supported
Shaun> rather than fall back to WS10.
I deliberately capped WRITE SAME to 64K blocks unless otherwise reported
by the device because:
a) Several older drives supported the WRITE SAME(16) command but
ignored the upper bytes of the transfer length effectively
turning it into a WRITE SAME(10).
b) 64K blocks was the sweet spot for older drives as well, a
size commonly used by RAID array firmwares that were the only
commonplace users of the WRITE SAME family.
Shaun> I really am not sure what would be considered the correct
Shaun> solution though. I believe that the WRITE SAME defaults are
Shaun> currently being chosen around physical limits.
Lacking a solid reporting facility in the spec, I suggest you just leave
it unset and let the SCSI defaults apply.
Shaun> I think we can also bump the command timeout for WRITE SAME?
The default WRITE SAME timeout is 120s.
--
Martin K. Petersen Oracle Linux Engineering