On 05/28/2010 10:20 AM, Douglas Gilbert wrote: > On 10-05-28 10:55 AM, bugzilla-daemon@xxxxxxxxxxxxxxxxxxx wrote: >> https://bugzilla.kernel.org/show_bug.cgi?id=16070 >> >> Summary: Fail to issue Start/Stop Unit >> Product: IO/Storage >> Version: 2.5 >> Kernel Version: 2.6.34-rc5 >> Platform: All >> OS/Version: Linux >> Tree: Mainline >> Status: NEW >> Severity: normal >> Priority: P1 >> Component: SCSI >> AssignedTo: linux-scsi@xxxxxxxxxxxxxxx >> ReportedBy: ian@xxxxxxxxxxxxxxxxxxxxx >> Regression: No >> >> >> I am attempting to save power by spinning down idle scsi disks. These >> are old >> fashioned parallel (U320) disks on a SCSI storage controller: LSI Logic / >> Symbios Logic 53c1030 PCI-X Fusion-MPT Dual Ultra320 SCSI (rev 07). >> >> I do: >> >> sg_start --stop /dev/sde >> echo 0xfffffff> /sys/module/scsi_mod/parameters/scsi_logging_level >> dd if=/dev/sde of=/dev/null count=1 >> sleep 10 >> echo 0> /sys/module/scsi_mod/parameters/scsi_logging_level >> >> I get: >> dd: reading `/dev/sde': Input/output error >> 0+0 records in >> 0+0 records out >> 0 bytes (0 B) copied, 0.00536828 s, 0.0 kB/s >> >> If I manually spin up the disk with sg_start --start /dev/sde, then >> things work >> again as expected. > > <snip> >> >> After getting: "Add. Sense: Logical unit not ready, initializing command >> required" I would expect a Start/Stop unit command, but it appears >> that none is >> ever issued. > > There is a different design philosophy between SCSI and > ATA disks (and has been for a very long time) reflecting > their different markets. When a SCSI disk is spun down, then > it will return errors on any command trying to do IO > until a SCSI START STOP UNIT command (start) is sent and then > time is allowed for the disk to spin up. > > What you report as a bug is the long standing behaviour of > SCSI disks which Linux has not tried to modify. If you set the allow_restart sysfs parameter on the disk, it should automatically spin up the disk when scsi eh sees that sense data. Thanks, Brian -- Brian King Linux on Power Virtualization IBM Linux Technology Center -- To unsubscribe from this list: 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
