Re: ThinkPad T41 - Strange USB 2.0 behaviour

From: Robert de Rooy
Date: Fri Jun 08 2007 - 06:09:50 EST

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.
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