On Tue, 2007-11-20 at 16:36 +0100, Oliver Neukum wrote: > Am Dienstag 20 November 2007 schrieb James Bottomley: > > > > On Tue, 2007-11-20 at 16:07 +0100, Oliver Neukum wrote: > > > Am Dienstag 20 November 2007 schrieb James Bottomley: > > > > I don't understand why you want to do this. Power management is a > > > > layered issue on SCSI, divided (as always) into host, device and > > > > transport. The idle you're talking about is a pure device thing, so it > > > > can be managed by the ULD (and currently is). When a unit is stopped, > > > > > > The lower layers don't know how to correctly suspend a device. sd_suspend() > > > may know how to do it. It would also mean the LLD having to detect idleness. > > > > You really mean you want to involve the transport as well, right? So > > Yes, we cannot avoid that. Some device drop their caches unless they are > flushed. So that would be fixed by having the ULD send a flush before START STOP UNIT? > > ipso facto this is more than simple idleness management. Thus, you > > really need to look into the full solution (host, transport and ULD). > > Only detecting idleness without doing anything with that knowledge would > be pointless :-) > What is the right kind of sequence? I don't really know ... I don't have a clear idea of what you're trying to do. I know Alan said it was something simple, but from what you're saying it sounds like you need a full blown power management infrastructure in all three places. 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
