Re: Regression in kernel 3.8-rc1 bisected to commit adfa79d: I nowget many "unable to enumerate USB device" messages

From: Alan Stern
Date: Thu Dec 27 2012 - 18:18:07 EST


On Thu, 27 Dec 2012, Larry Finger wrote:

> I could not do exactly the experiment that you wanted, as ehci-hcd was loaded
> even though it was blacklisted. Rather than solve that problem, I generated a
> kernel from just before commit adfa79d with ohci-hcd built in and ehci-hcd as a
> module. This one generated the errors, but they stopped when ehci-hcd loaded. I
> also tested a 3.8-rc1 kernel with ehci-hcd and ehcd-pci built in and ohci-hcd as
> a module. No errors for that one. Your hypothesis looks correct.
>
> I hope there is some way to force ehci-pci to load as soon as ehci-hcd is
> loaded, and before ohci-hcd loads, but if there is not, I know how to prevent
> the errors on my system even though this solution won't help the users of distro
> kernels. At least this time the errors stop once all 3 modules are loaded, and
> the number of error outputs is limited.

This is now a userspace issue. Perhaps a change to a udev rule will
prevent ohci-hcd from loading until ehci-pci is in place. Or a change
to a startup script in your initramfs. However the problem gets
solved, there doesn't seem to be much the kernel can do about it.

Alan Stern

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/