Re: ThinkPad T41 - Strange USB 2.0 behaviour

Robert de Rooy
2007-06-08T10:09:47Z

Jiri Kosina wrote:
> On Thu, 7 Jun 2007, Robert de Rooy wrote:
>
>
>> Yes I figured it was a hardware problem, but that was not really the
>> point I was trying to raise ;). I would like, if possible for Linux to
>> automatically fallback to USB 1.1 like Windows does (preferably with a
>> suitable warning).
>>
>
> What do you propose as a trigger for the kernel to fallback?
>
> You can work it around manually, just don't use ehci-hcd, can't you?
>
>
Yes I can unload ehci-hcd, but I have one USB 2.0 device that strangely
enough DOES work as such, and unloading ehci-hcd will cause that also to
run at 1.1 speed.

Clearly something is failing when plugging a device with ehci-hcd
loaded, the driver seems to keep retrying indefinitely. Instead it would
be nice if after a few tries it hands the device over to uhci-hcd. This
seems to be the behaviour under Windows, so I was wondering if Linux
could be made to do something similar.