Re: [RFC] Implementation of SCSI dynamic power management

Oliver Neukum
2008-01-09T16:10:59Z

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

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