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 We have a sequence: a) stop further block requests b) sync the disk (and sync the cache -- there was talk on and off for several years about sync not realling syncing) c) drop power on the disk We tweak the ext3 mount timeout and the /proc/sys/vm settings to put the computer into laptop mode. When a read comes along, we reverse the process...(or a forced write which generally won't happen). But we need to add patches to the device driver and the block layer to enable this...it seems useful if there was a more generic way to handle it...maybe registering a callback to reenable power and a mechanism to start the poweroff sequence... We've done this in 2.6.20, I wonder if there's any work along these lines in recent kernels (I'm going to look at 2.6.2[67]...) Marty > -----Original Message----- > From: linux-pm-bounces@xxxxxxxxxxxxxxxxxxxxxxxxxx [mailto:linux-pm- > bounces@xxxxxxxxxxxxxxxxxxxxxxxxxx] On Behalf Of Alan Stern > Sent: Wednesday, August 13, 2008 3:37 PM > To: Oliver Neukum > Cc: 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, Oliver Neukum wrote: > > > > In Alan's patch, SCSI calls scsi_host_template methods (if the LLD > > > provides ones) to suspend and resume a Scsi_Host. The LLD can use > them > > > to work with the underlying infrastructure to determine what can be > done > > > at that time. I.e. are there other protocols or other initiator- > like > > > nodes sharing the link? If yes or if "maybe yes", the > infrastructure > > > keeps the link up. If not, it can move it into a low-power state. > > > > That is a parculiar way of viewing it. Alan's patch introduce runtime > > pm attributes to the devices. Quoting: > > > > With the original patch, you can't operate on the link independent from > the devices. But with the revised patch (whenever I manage to find > time to write it!), you _will_ be able to. > > Alan Stern > > _______________________________________________ > linux-pm mailing list > linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx > https://lists.linux-foundation.org/mailman/listinfo/linux-pm _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
