This patch adds SATAII NCQ support to libsas. Both the use_ncq and the
dma_xfer flags in ata_task must be set for NCQ to work correctly on the
Adaptec SAS controller. The rest of the patch adds ATA_FLAG_NCQ to
sata_port_info and sets up ap->scsi_host so that ata_setup_ncq doesn't
crash. Please note that this patch is against the aic94xx-sas git tree,
not scsi-misc. Thanks also to James Bottomley for providing an earlier
version of this patch from which to work.
I've tested this patch on a x206m with a ST380819AS SATA2 disk plugged
into the Adaptec SAS controller. The drive came up with a queue depth
of 31, and I successfully ran an I/O flood test to coerce libata into
sending multiple commands simultaneously. A kernel probe recorded the
maximum tag number that had been seen before and after the flood test;
before the test it was 2 and after it was 30, as I expected.
Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
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