Commit bdab4e87 authored by Darrick J. Wong's avatar Darrick J. Wong Committed by James Bottomley
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[SCSI] libsas: support NCQ for SATA disks

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: default avatarDarrick J. Wong <>
Signed-off-by: default avatarJames Bottomley <>
parent 797f49de
......@@ -828,8 +828,14 @@ static unsigned int sas_ata_qc_issue(struct ata_queued_cmd *qc)
task->ata_task.retry_count = 1;
task->task_state_flags = SAS_TASK_STATE_PENDING;
if (qc->tf.protocol == ATA_PROT_DMA)
switch (qc->tf.protocol) {
task->ata_task.use_ncq = 1;
/* fall through */
task->ata_task.dma_xfer = 1;
if (sas_ha->lldd_max_execute_num < 2)
res = i->dft->lldd_execute_task(task, 1, GFP_ATOMIC);
......@@ -962,7 +968,7 @@ static struct ata_port_operations sas_sata_ops = {
static struct ata_port_info sata_port_info = {
.pio_mask = 0x1f, /* PIO0-4 */
.mwdma_mask = 0x07, /* MWDMA0-2 */
.udma_mask = ATA_UDMA6,
......@@ -1031,6 +1037,7 @@ int sas_target_alloc(struct scsi_target *starget)
ap->private_data = found_dev;
ap->cbl = ATA_CBL_SATA;
ap->scsi_host = shost;
found_dev->sata_dev.ap = ap;
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