Re: [PATCH] libsas: support NCQ for SATA disks

[James Bottomley <James.Bottomley@SteelEye.com>]

On Fri, 2006-10-13 at 16:56 -0700, Darrick J. Wong wrote:
> 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.

This doesn't seem to quite work for me on a SATA-1 disc:

sas: DOING DISCOVERY on port 1, pid:1897
sas: sas_ata_phy_reset: Found ATA device.
ata1.00: ATA-7, max UDMA/133, 781422768 sectors: LBA48 NCQ (depth 31/32)
ata1.00: configured for UDMA/133
scsi 2:0:1:0: Direct-Access     ATA      ST3400832AS      3.03 PQ: 0
ANSI: 5
SCSI device sdc: 781422768 512-byte hdwr sectors (400088 MB)
sdc: Write Protect is off
SCSI device sdc: drive cache: write back
SCSI device sdc: 781422768 512-byte hdwr sectors (400088 MB)
sdc: Write Protect is off
SCSI device sdc: drive cache: write back
 sdc: unknown partition table
sd 2:0:1:0: Attached scsi disk sdc
sas: DONE DISCOVERY on port 1, pid:1897, result:0
sas: command 0xf785f3c0, task 0x00000000, timed out: EH_HANDLED
sas: command 0xf785f3c0, task 0x00000000, timed out: EH_HANDLED
[...]

It looks like the first few commands get through (read capacity, ATA
IDENTIFY etc) and it hangs up on the read for the partition table.

James