Re: USB autosuspend vs. URB submission

[Josh Boyer]

On Tue, Jan 08, 2013 at 10:51:20AM -0500, Alan Stern wrote:
> On Mon, 7 Jan 2013, Josh Boyer wrote:
> 
> > Hi,
> > 
> > We've had a few reports in Fedora of users hitting the WARN_ONCE in
> > drivers/usb/core/urb.c that prints a warning about a usb_submit_urb
> > being called on an active URB.  One of them[1] is from the ums_realtek
> > driver and the other[2] is from the uvcvideo driver.  However, I noticed
> > that in both instances it seems the devices were coming back from what I
> > think is autosuspend.
> > 
> > I didn't immediately find any similar reports, and to my rather
> > inexperienced eyes the drivers didn't seem to be doing anything clearly
> > wrong.  I'm wondering if anyone has some possible ideas for debugging
> > and whether or not this might be a general issue?
> 
> I don't see anything wrong either.
> 
> Can you ask the users to collect a usbmon trace covering the period 
> when the problem occurs?

I'll certainly ask.  I'm not particularly hopeful for great results
though, as the problems seem to be rather intermittent.

Thanks for taking a look.

josh
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