On Wed, 26 Mar 2014, Peter Münster wrote:
> On Wed, Mar 26 2014, Alan Stern wrote:
>
> > Please try running the test again. When it finishes, go to the
> > /sys/kernel/debug/usb/ohci/0000:00:12.1/ directory and post a copy of
> > the "registers" file.
> >
> > Check the contents of that file several times; in the line that says
> > "hcca frame", the value should change over time. Does it?
>
> Yes, it does.
>
> Please find attached the kernel messages and the output of this command:
>
> while sleep 1; do date; cat registers; echo; done >/tmp/registers.log
Oops -- I just realized that the instructions I sent you before were
incomplete. Please try running the same test again, but this time
issue the following commands to suspend the device:
echo on >/sys/bus/usb/devices/4-2/power/control
echo 0 >/sys/bus/usb/devices/4-2/bConfigurationValue
echo auto >/sys/bus/pci/devices/0000:00:12.1/power/control
echo auto >/sys/bus/usb/devices/4-2/power/control
Then a few seconds later, the following command to resume the device:
echo on >/sys/bus/usb/devices/4-2/power/control
Without the write to the PCI device, the USB controller did not go into
suspend and so it wasn't a valid test.
As for the changing hcca frame value, that was just a wild guess on my
part. Still, if you find it's _not_ changing after this new test, that
would explain the problem you experienced.
Alan Stern
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