Re: So, what's the status on the recent patches here?

Alan Stern
2006-08-25T21:46:47Z

On Fri, 25 Aug 2006, Pavel Machek wrote:

> Hi!
>
> > > The frequency of entering this state should not interfere with my active
> > > use case.
> > >
> > > -B- After I've put down the USB device, I now can program the internal
> > > SOC bus wrapper for the USB to allow idling of the interconnect. I also
> > > need to associate the USB remote wake interrupt with a wake up interrupt
> > > to restart my interconnect. All devices on that interconnect must be in
> > > the same state for the big savings to happen.
> > >
> > > Certainly for this embedded system, not coordinating the device states
> > > means I can't get the big power savings.
> >
> > Part of this programming has to be done in the architecture-specific
> > driver for the interconnect. There already is code being developed to
> > suspend USB buses when they aren't in use (although determining _when_
> > they aren't in use has not yet been implemented). However this code
> > stops
>
> Are there some patches to test? I'd like to power down USB bus, even
> when it has device connected (I do not user fingerprint scanner that
> much).

There are some old patches. I could update them to the current -mm kernel
and post them next week.

The idea of the patches is that they will autosuspend a USB hub when it
has no active (i.e., unsuspended) children, and autosuspending a root hub
stops the USB controller from doing DMA. However, non-hub devices are not
yet automatically suspended, so you will have to suspend the fingerprint
scanner by hand.

Alan Stern