On Wednesday, March 01, 2006 4:51 PM, Quat Le wrote:
I cannot tell if the LSI SAS HBA driver uses libata or not. A week ago I
did send LSI tech support a question asking if the SCSI-to-ATA
Translation Layer is done in the HBA driver or in a different layer on
Linux. So far I have not gotten any response. That's a good idea to
try this on a SATA disk connected to a SATA HBA. I will try this.
No, the mptsas driver is not using libata, however we are using
scsi_transport_sas.
This is firmware assist implementation, meaning SCSI-to-ATA translation
is done in firmware; via queue_command entry point, all commands
to both SAS and SATA devices are sent via SCSI_IO passthru. Is the SG_IO
ATA passthru encapsalating an ATA command inside a SCSI CDB?
If so, I don't think the firmware folks have not implemented that yet.
When that is completed, I expect no change in driver, as its simply
passthru, and the firmware will handle the request. There is an alternative,
you can send an IOCTL=MPT_COMMAND IOCTL using
the mptctl driver with the function set to
MPI_FUNCTION_SATA_PASSTHROUGH.
I thought support for those two opcodes went into libata
for lk 2.6.15 as well but haven't written discrete code
to test it. Does the lsi SAS HBA use libata on its STP
(or direct connect) path? Eyeballing the libata code,
those opcodes are used internally. I know that
"smartctl -a -d ata /dev/sda" works when /dev/sda is a
SATA disk using libata on a regular SATA HBA. At present I
do not have any hardware nearby to test it. If you can direct
connect a SATA disk to a SATA controller on your motherboard
(i.e. bypassing the SAS HBA) does that make any difference?
What is smartctl? Is that part of Doug's sg_tools, or something else.
Eric Moore
LSI Logic
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