Re: [linux-usb-devel] 2.6.18-rc6-mm1 (-mm2): ohci resume problem

Rafael J. Wysocki
2006-09-14T20:22:07Z

On Thursday, 14 September 2006 21:37, Rafael J. Wysocki wrote:
> On Thursday, 14 September 2006 20:28, Alan Stern wrote:
> > On Thu, 14 Sep 2006, Rafael J. Wysocki wrote:
> >
> > > > Let's try a simpler test. Leave USB_SUSPEND unset.
> > > >
> > > > First rmmod ohci-hcd. None of your full-speed USB devices will work, but
> > > > that's okay. Try the suspend-twice test and see what happens.
> > > >
> > > > Second, rmmod ehci-hcd and modprobe ohci-hcd. Again try the suspend-twice
> > > > test.
> > >
> > > Done, works (with USB_SUSPEND unset).
> >
> > Okay, good.
>
> Well, sorry. This test has been passed, but after a reboot it refused to
> suspend just once giving the same messages that I've got from the kernel
> with USB_SUSPEND set (the relevant dmesg output is attached).

This only happens if _both_ ohci_hcd and ehci_hcd are loaded before the
suspend.

> > Then for the next stage, repeat the same tests but with
> > USB_SUSPEND set.
>
> Compiling.

The results are now the same with and without USB_SUSPEND set. Namely,
if one hcd is loaded before a suspend (either ehci or ohci), it succeeds
(repeatable arbitrary number of times in a row). However, if both hcds are
loaded before a suspend, it fails (100% of the time) and the messages are
like in the dmesg output attached to the previous message.

I've reproduced this behavior on another x86_64 box.

Greetings,
Rafael

--
You never change things by fighting the existing reality.
R. Buckminster Fuller