Bartlomiej Zolnierkiewicz wrote: > On 12/2/05, Jeff Garzik <jgarzik@xxxxxxxxx> wrote: > >>Bartlomiej Zolnierkiewicz wrote: >> >>>On 11/24/05, Jeff Garzik <jgarzik@xxxxxxxxx> wrote: >>> >>> >>>>Douglas Gilbert wrote: >>>> >>>> >>>>>I don't think a SATL is that easy. One SCSI command can >>>>>translate into zero or more ATA commands. If it translates >>>>>to multiple commands, then there is the possibility of an >>>>>error prior to the last in the sequence of ATA commands >>>>>(how to report; rollback needed ?). The SATL needs to hold >>>>>state and needs a service thread if it is to support the >>>>>IMMED bit on some commands (e.g. START STOP UNIT). >>>> >>>>It needs a conceptual service thread, not necessarily an explicit one. >>>> >>>>With REQUEST SENSE, I've demonstrated how to report errors with each >>>>step in the sequence. With demo patches I've posted, I've demonstrated >>>>(using qc->private_data) how to hold state. >>>> >>>> >>>> >>>> >>>>>libata still has a ways to go to catch up to SAT rev 7 >>>>>but has made some good progress lately with the addition >>>>>of the ATA pass through commands (lk 2.6.15-rc1 and onward). >>>>>smartmontools (just prior to 5.34) now works with '-d ata' >>>>>on libata-connected SATA disks. The '-d ata' ** overrides >>>>>the guess of a SCSI disk based on the device node (e.g. >>>>>/dev/sda) and uses the HDIO_DRIVE_CMD and HDIO_DRIVE_TASK >>>>>ioctls. The absence of support for the HDIO_DRIVE_TASKFILE >>>>>ioctl means that "selective" self-test can't be done. >>>>>I'm not sure if moving smartmontools to the ATA PASS THROUGH >>>>>SCSI commands will win back the "selective" self-test >>>>>capability. Anyway, going to those ATA PASS THROUGH SCSI >>>> >>>>ATA passthru can do anything the legacy IDE ioctls can do (and more). >>> >>> >>>[ definitely ATA passthru is the way to go but... ] >>> >>>discrete taskfiles? >> >>what is this? > > > flagged taskfiles > > yes, this is a low priority but your statement is oversimplification > and I don't even mentioned other "IDE ioctl", so: > > ATA passthru can do anything _important_ that legacy IDE ioctls > can do (write cache [dis,en]abling?) > > >>>multi-PIO? >> >>what is this? multi-sector PIO, such as READ MULTIPLE SECTORS? ATA > > > short for multi sector-sector PIO > > >>passthru can do that. > > > not in the mainline, I've just checked libata-dev and it is OK > > >>>setting transfer speed? >> >>That's not a limitation of passthru, but a limitation of the driver. I >>don't yet see the value... > > > Same for me... I noticed that the protocol field in the ATA_12 and ATA_16 pass through commands included hard reset, SRST and device reset. Would it be useful to implement these? Doug Gilbert - : send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
