On Sat, 2007-01-20 at 12:22 +0900, 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 are practical problems to handling this in sd, namely that the power handling commands and state model are part of the ATA command set, not part of the SCSI command set. SAT really only covers the basics of mapping the different power management models. However, I suppose if we're going to allow stop on shutdown, it does make sense to use it on suspend as well. James - 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
