Re: [PATCH] USB: disable autosuspend by default for non-hubs

On Tue, 21 Aug 2007, Greg KH wrote:

> On Mon, Aug 20, 2007 at 10:48:05AM -0400, Alan Stern wrote:
> > This patch (as965) disables autosuspend by default for all USB devices
> > other than hubs.  We are seeing too many devices that can't suspend or
> > resume properly, the blacklist is growing unreasonably quickly, and
> > this sort of thing should be handled in userspace.
> > 
> > Signed-off-by: Alan Stern <[email protected]>
> > 
> > ---
> > 
> > Once this is added there isn't much point in keeping the
> > USB_QUIRK_NO_AUTOSUSPEND flag or usbcore's "autosuspend" parameter.
> > But one thing at a time.
> > 
> > It would be a good idea to put this in 2.6.23.  If it turns out not to
> > be necessary we can always remove it later; the conservative course for
> > now is to avoid breaking lots of devices all at once.
> 
> But with a simple config change, those devices are not broken, right?

Right, turning off CONFIG_USB_SUSPEND makes this issue moot.  The
downside is it also prevents the system from suspending hubs with no
active children, which currently works just fine as far as I know.

(For root hubs at least this doesn't matter so much, since the host 
controller drivers will turn off most of the root hub functions anyway 
when no children are attached.)

> And right now, no distro is enabling that option, so we are safe for a
> bit.
> 
> And I really don't want to apply this patch, as it is very broad.
> 
> Perhaps the best solution for the autosuspend stuff _is_ to do it in
> userspace, but I'm not quite sold on that yet, as that infrastructure is
> not in place, nor do we really know how that will look.

Can we at least make a start on getting that infrastructure developed?  
Who are the right people to talk to about this?  
[email protected] and who else?

> So, I'd really like to stick with what we have for now, as imperfict as
> it might be, and work on adding suspend support to the different
> drivers.

Okay.  What about Oliver's suggestion not to autosuspend devices by
default if they don't have any interface drivers bound?

Alan Stern


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