Re: Problems with p55-express and sleeping usb-hds

Alan Stern
2009-11-18T16:22:23Z

On Wed, 18 Nov 2009, Alexander Holler wrote:

> Hello,
>
> I've done some more tests and have some more findings.
>
> After the problem occured (which looks for me like a timeout during a
> wait for a CSW), ehci_hcd doesn't work anymore. Low- and full-speed
> devices are still working and are recognized correctly, but no
> high-speed device. After unloading ehci_hcd and reloading it, high-speed
> devices are recognized correctly again.
> As unloading is no option for kernels which have ehci_hcd compiled in
> (like the F11-kernel), is there another option to reset the driver?

You can unbind ehci-hcd from the controller by writing the controller's
name to the "unbind" attribute in the appropriate sysfs directory. For
example, on my system:

# ls /sys/bus/pci/drivers/ehci_hcd
0000:00:1d.7 0000:01:00.2 0000:01:01.2 bind module new_id uevent
unbind
# echo -n 0000:00:1d.7 >/sys/bus/pci/drivers/ehci_hcd/unbind

Then to rebind the driver, write the device name to the "bind"
attribute:

# echo -n 0000:00:1d.7 >/sys/bus/pci/drivers/ehci_hcd/bind

Alan Stern