On Thu, 19 Jun 2014, Dennis New wrote:
> On Thu, 19 Jun 2014 17:03:55 -0400 (EDT), Alan Stern wrote:
> > On Tue, 17 Jun 2014, Dennis New wrote:
> >
> > > On Thu, 12 Jun 2014 10:20:54 -0400 (EDT), Alan Stern wrote:
> > > > Dennis and Matteo:
> > > >
> > > > I promised to send both of you a patch changing the way ohci-hcd
> > > > handles hardware bugs. Well, it's finally ready for testing.
> > > > There's only a limited amount I can do on my own machine, so now
> > > > it's up to you guys.
> > > >
> > > > The patch was made against an early -rc version of 3.15, but it
> > > > will apply okay to 3.14 and maybe even earlier kernels.
> > >
> > > So, it happened again, after a random few days, this time with
> > > dmesg a bit different:
> > >
> > > [210263.872368] ohci-pci 0000:00:13.0: frame counter not updating;
> > > disabled
> > > [210263.872377] ohci-pci 0000:00:13.0: HC died; cleaning up
> > > [210263.872456] usb 2-4: USB disconnect, device number 4
> > > [210264.872344] timeout: still 2 active urbs on EP #3
> > >
> > > The frame counter indeed was not updating. I notice that this time,
> > > it says there are "still 2 active urbs", whereas before it always
> > > said 3. I also noticed that before I would still get "USB
> > > disconnect" messages when I unplugged my device, but not this time.
> > > It looks like there was a more thorough disabling of the usb/ohci
> > > system this time.
> >
> > That "timeout:" message came from the snd-usb-audio driver. I don't
> > know if the number of URBs is especially significant, probably not.
> > The lack of "USB disconnect" messages is expected, because as you
> > realized, the OHCI driver was disabled.
> >
> > Anyway, it looks like things are working better than they did
> > before. Your system isn't crashing when the problem occurs, right?
> > This might not be the solution you wanted, but I think it's the best
> > we can do.
>
> My system didn't really crash before either -- just the ohci. I forget
> if the process that was using the snd-usb-audio driver remained hung in
> the background, but commands like "lsusb" do not work. I am forced to
> reboot to get ohci-usb working again :\. Isn't there a way to reset the
> ohci subsystem? :s
And with the patch, lsusb and the sound processes do work after the
fault? I want to make sure, since you didn't say explicitly.
You can restart the OHCI controller by this sequence of commands:
echo 0000:00:13.0 >/sys/bus/pci/drivers/ohci_pci/unbind
echo 0000:00:13.0 >/sys/bus/pci/drivers/ohci_pci/bind
However, some USB devices can't recover from this sort of event until
they have been unplugged. I tried it with two flash drives plugged in;
afterwards one of them worked and the other didn't.
Alan Stern
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