Am Donnerstag 14 August 2008 15:50:21 schrieb Pavel Machek: > On Wed 2008-08-13 18:21:29, Oliver Neukum wrote: > > Am Mittwoch 13 August 2008 17:44:46 schrieb Alan Stern: > > > > All children that are USB must be powered down. We know in fact that most > > > > drives don't care that the device is suspended. The problem was drive > > > > enclosures that cut power upon suspension losing cached data. > > > > > > You misunderstood my question. Are there SCSI transports other than > > > USB sharing the requirement that all child devices must be suspended > > > before the link can be powered down? > > > > I dispute that USB in general has this property. Some storage devices > > need their caches flushed. USB itself is perfectly happy with autosuspending > > the storage device (host) without telling the disks (devices) > > > > You could even argue that these storage devices violate the USB spec. > > Hmm... but suspended devices have very little power budget, right? > > So unless you have external power supply (2.5" frames generally > don't), you can't really suspend and stay spinned up... > True, but the spec says that no state shall be lost. I don't really argue against flushing the caches. But I cannot that this would demand that we should implement autopsuspend for SCSI. It seems like overengineering to me. Regards Oliver _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
