[ltp] usb 2.0 operating as usb 1.1

Matthias Himber linux-thinkpad@linux-thinkpad.org
Thu, 9 Jun 2005 16:15:49 +0200

Short answer: your southbridge is about to die, get your system board 
replaced. Hopefully its still under warranty.

Long answer: a number of Intel chipsets for Pentium IV and Pentium M 
processors have a design flaw that makes the southbridge (which contains the 
USB host controllers) especially sensitive to static electricity. As a result 
there is a (small) risk that when plugging in or removing a USB device causes 
damage to the chip. Usually, the first symptom is broken USB 2.0, behaving in 
exactly the way you described (ie, works under Windows, but only after some 
waiting and as if it was connected to a USB 1.1 controller, not a USB 2.0 
one, and not at all under Linux unless you unload the USB 2.0 driver). This 
tends to lead to a completely dead chipset a short time later, so better get 
it serviced NOW.
Incidentially, exactly this happened to me around last Christmas. Same 
Thinkpad model, too.


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