No NCQ support on X61s Ultrabay? (Intel ICH8 SATA controller question)

From: Theodore Ts'o
Date: Wed Apr 29 2009 - 22:07:49 EST


I was taking a look at why I can't get NCQ working on the Ultrabay drive
on the X61s Thinkpad (which is a big deal if you're using the X25-M
SSD):

[ 4563.614247] ata4.00: 390721968 sectors, multi 16: LBA48 NCQ (depth 0/32)
^^^^^^^

which as near as I can tell is because ATA_FLAG_NCQ isn't set in struct
ata_port->flag. This looks like it should be set to ata_piix.c if the
controller supports NCQ --- but ata_piix.c doesn't set ATA_FLAG_NCQ at
all. However, this web page:

http://www.intel.com/support/chipsets/imst/sb/CS-012304.htm

Seems to imply the 82801HBM/HEM SATA controller from the ICH8M/ICHM8-E
supports AHCI and NCQ, and this is the controller which is in the X61s
laptop.

So I wonder if it's safe to simply add ATA_FLAG_NCQ to ata_piix.c or
not? Can someone who's more familiar with Intel's ICH8 SATA controller
comment on whether this would be a safe thing to do?

Thanks,

- Ted
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