Re: Regression 3.0-rc5+ : khubd blocked

From: Alan Stern
Date: Fri Jul 01 2011 - 16:40:13 EST


On Fri, 1 Jul 2011, Sarah Sharp wrote:

> On Fri, Jul 01, 2011 at 01:19:23PM -0400, Alan Stern wrote:
> > On Fri, 1 Jul 2011, [ISO-8859-1] ?ric Piel wrote:
> >
> > > Sorry, but from a quick look, it seems to not fix the bug.
> > >
> > > I'll try further on Monday.
> >
> > Do you get a similar message from the task watchdog? The patch should
> > have caused usb_set_interface() to return early, without trying to
> > acquire the mutex that caused the problem before.
>
> I've been able to reproduce this bug with linus/master. When I apply
> your patch (or at least change the code to match your patch, since I
> don't have those top-level directories),

What top-level directories? You're not referring to the dummy
"usb-3.0.orig" and "usb-3.0" path components in the patch? They don't
matter if you use "patch -p1".

> I can successfully unplug and
> replug in a hub with a keyboard and mouse attached to it, with no hangs.
> So I'm not sure why it isn't working for Éric.
>
> One further complication of the original patch is that when the xHCI
> driver is unloaded, usb_disable_device is called for devices under the
> USB 2.0 split rootub after the USB 3.0 roothub has been unregistered and
> the xHCI host is halted. The configure endpoint code doesn't actually
> check if the hardware is running before submitting commands, so it takes
> about 30 seconds for the command for each device to timeout. So that
> needs to be fixed as well.
>
> Do you mind if I just take your patch and make a proper fix out of it?

Don't bother; I'll send it in to Greg momentarily (along with your
Tested-by if you don't mind).

Alan Stern

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