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

[Alan Stern]

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

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