Re: question on flushing buffers and spinning down disk
Oliver Neukum <[email protected]>
| Newsgroups | gmane.linux.scsi,gmane.linux.usb.devel |
|---|---|
| Message-ID | <[email protected]> |
Am Montag 24 September 2007 schrieb Alan Stern: > On Mon, 24 Sep 2007, Oliver Neukum wrote: > > > Am Dienstag 18 September 2007 schrieb James Bottomley: > > > On Tue, 2007-09-18 at 16:15 +0200, Oliver Neukum wrote: > > > > > It is for runtime power management. We've gotten a bug report about > > > > a drive enclosure that doesn't properly park heads if the usb device is > > > > simply suspended. Apparently it simply cuts power so the cache can > > > > be lost, too. > > > > > > But even for runtime, if you want to suspend the device, shouldn't you > > > be calling the suspend methods in the device tree? > > > > Very good question. It seems to that yes indeed, we should. But we don't > > in case of autosuspend. We simply suspend the interfaces: > > It's a loaded question. The fact is, the existing suspend methods in > the device tree are intended for system-wide suspend, not for runtime Unfortunately true. > suspend. The PM and driver cores don't include _any_ provision for > runtime suspend; it has to be managed separately by each subsystem. There we have a problem. We'd have to solve it for each subsystem transition. Storage has this type of children, other devices will have to care for other types of child devices. If we have a device tree, we should use it. Regards Oliver - To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html