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.
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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. Doug Gilbert -- 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
