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SubjectRe: [34-stable regression] USB delay init quirk causes device events loss
On Mon, Sep 13, 2010 at 11:37:49AM -0400, Alan Stern wrote:
> On Mon, 13 Sep 2010, Jiri Slaby wrote:
>
> > On 09/13/2010 04:48 PM, Alan Stern wrote:
> > > On Mon, 13 Sep 2010, Jiri Slaby wrote:
> > >> In other words, what I could do is to add some printks into
> > >> hub_port_connect_change if that's called at all. If you need some
> > >> thorough debugging printks, please send me a patch to test instead.
> > >
> > > Hmm. I'd prefer to explain how it's all supposed to work and let you
> > > figure out where best to look. Or try to debug it myself. Does this
> > > happen with other sorts of USB devices as well, or just wacom?
> >
> > With some sort of devices (I cannot reproduce myself). It's unrelated to
> > wacom -- people with wacom were unable to even start X with this kernel.
> > If you look at the bugreport, there are several examples:
> > ID 046d:c517 Logitech, Inc. LX710 Cordless Desktop Laser defunct
> > Microsoft USB keyboard defunct x Logitech mice OK
> > 046a:0021 Cherry GmbH keyboard defunct
> > logitech wireless laptop mouse defunct
> > A$Tech wireless laptop mouse defunct
> > TypeMatrix USB 2030 (ID : 1e54:2030) defunct
>
> Okay, I see the problem. By moving usb_detect_quirks earlier, we end
> up calling usb_disable_autosuspend too soon -- before the
> pm_runtime_enable call in usb_new_device. In 2.6.35 this doesn't
> matter because the implementation of usb_autosuspend_device has
> changed.
>
> So yes, in the end it looks like the best course is to revert this
> patch from 2.6.34.stable. This is unfortunate but I don't see any way
> around it without making changes that aren't present in the current
> kernel. For example, the pm_runtime_set_active and pm_runtime_enable
> calls could also be moved from usb_new_device into
> hub_port_connect_change.

Ok, I'll go revert that from the .34-stable tree and do a new release,
as it's not nice to have a broken tree out there.

thanks,

greg k-h


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