linux-kernel - Re: Nobody cared about IRQs at shutdown

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Date:	Thu, 25 Nov 2010 15:25:10 -0500 (EST)
From:	Alan Stern <stern@...land.harvard.edu>
To:	"Alexander E. Patrakov" <patrakov@...il.com>
cc:	linux-kernel@...r.kernel.org, <linux-usb@...r.kernel.org>
Subject: Re: Nobody cared about IRQs at shutdown

On Thu, 25 Nov 2010, Alexander E. Patrakov wrote:

> 25.11.2010 21:06, Alan Stern wrote:
> > On Thu, 25 Nov 2010, Alexander E. Patrakov wrote:
> >
> >> Hello.
> >>
> >> After switching my Gentoo desktop from sysvinit + openrc to systemd, I
> >> started getting "nobody cared" messages about IRQs 16 and 19 (common
> >> thing: they are assigned to the USB controllers, that's why CC:
> > According to your listing, they are used by uhci-hcd.  Do the messages
> > go away if you unload uhci-hcd before shutting down?
> 
> It is not a module here, so I have to recompile the kernel in order to 
> try this. Will do that tomorrow.
> 
> > You may need to debug the uhci-hcd driver. Look into
> > drivers/usb/host/uhci-hcd.c; the uhci_shutdown() routine ought to be
> > called and it ought to call uhci_hc_died(), which in turn calls
> > uhci_reset_hc() in pci-quirks.c, which is supposed to prevent the
> > controller from generating any IRQs.
> 
> OK, tomorrow I will add some printks there.
> 
> > Do you have any USB devices attached to bus 3 or bus 6?
> 
> Yes:
> 
> Bus 006 Device 002: ID 05d8:4002 Ultima Electronics Corp. Artec Ultima 
> 2000 (GT6801 based)/Lifetec LT9385/ScanMagic 1200 UB Plus Scanner
> 
> Should I unplug it and retest the bug now?

Sure.

Even without rebuilding the kernel, you can unbind the uhci-hcd driver 
from the hardware by going to the /sys/bus/pci/drivers/uhci_hcd 
directory and doing:

	echo -n device-name >unbind

where "device-name" is the name of one of the symlinks in that 
directory.

Alan Stern

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