Being able to drop power on the disk on demand is a useful concept. We do it, but need a number of custom patches in a number of places. When the system WANTS to access the disk, it does what is necessary to get the disk to spin up... I'm not sure dropping disk power in a control way should trigger a hot-plug event --if everyone EXPECTS it. I'm just looking for a more generic way to enable this...I'm going to be looking a 2.6.26/27 for this soon... marty > -----Original Message----- > From: Alan Stern [mailto:stern@xxxxxxxxxxxxxxxxxxx] > Sent: Wednesday, August 13, 2008 4:39 PM > To: Leisner, Martin > Cc: Oliver Neukum; Linux-pm mailing list; kernel list; teheo@xxxxxxxxxx; > James.Bottomley@xxxxxxxxxxxxxxxxxxxxx; Pavel Machek; Stefan Richter > Subject: RE: Power management for SCSI > > On Wed, 13 Aug 2008, Leisner, Martin wrote: > > > Regarding these scsi suspend patches, there's a general > > problem to drop power on disk devices on a running system. > > I discussed it in: > > > > http://www.gossamer-threads.com/lists/linux/kernel/811598 > > There's a much worse problem which that thread completely ignored: > > When you turn off power to a disk device, to the system it looks like a > hot-unplug event. Any mounted filesystems or memory mappings on that > disk will be lost. > > Alan Stern _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
