Tejun Heo wrote:
Darrick J. Wong wrote:
Tejun Heo wrote:
sd doesn't stop (unload head) on shutdown. This behavior is necessary
for multi initiator cases. Unloading head by powering off stresses
the drive and sometimes produces distinct clunking noise which
apparently disturbs users considering multiple reports on different
distributions. halt(8) usually puts the drives to sleep prior to
shutdown but the implementation is fragile and it doesn't work with
sleep-to-disk.
I wonder if this sort of thing (cache flush + spin down) is the sort of
thing that ought to be done to near-line storage at suspend time too,
though one would want allow_restart = 1 before doing such a thing.
For ATA, it's currently being done inside libata proper (a bit ugly).
It would be nice to have those implemented at sd layer but I wonder how
useful it's going to be for actual SCSI devices. Do people actually
suspend using SCSI? If it's useful at the SCSI layer, I can implement
and test it with SATA devices here.
There is always the open question for multi-initiator SCSI devices, as
to who "owns" the SCSI device. Some devices should be suspended/stopped
when the machine is suspended/stopped, others not.
Jeff
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