Re: [RFC] Implementation of SCSI dynamic power management
From: Oliver Neukum <oliver@neukum.org>
Date: 2008-01-09 16:11:32
Am Montag, 7. Januar 2008 20:42:23 schrieb Alan Stern:
When all the devices under a host are suspended, the LLD is informed (via a new "autosuspend" method in the host template) so that it can put the host adapter in a low-power state. Likewise, a new "autoresume" method is called when the host adapter needs to return to full power. An implementation of these methods for the usb-storage driver will be posted in a followup patch.
This has an interesting implication. As the storage driver can share a device with in principle any other usb driver, we must audit all usb drivers if we wish to adopt this patch. All a device's interfaces must be resumed when the storage interface is resumed. To resume a storage device no memory must be allocated because that could deadlock. Regards Oliver