Comment 3 for bug 61235

I can confirm this happening on two Centrino Duo laptops. The problem is quite fascinating in my testing: (fascinating meaning that the ubuntu kernel team should probably reach for aspirin before reading on)

(1) It happens only when certain USB mass storage devices AND certain USB controllers are combined. A RockChip USB MP3 player and the Centrino Duo causes this to happen, while a Sandisk MP3 player (or a no-name external hard drive) and the same USB chipset does not cause the problem.

(2) The problematic device, when connected to my NForce3 based desktop running an identical Ubuntu setup, does not cause this problem.

(3) The problematic device connected to another different brand laptop using the same USB chipset causes the problem.

(4) Under Windows XP, everything works happily.

(5) rmmodding ehci-hcd (disabling USB 2.0) prevents the device from unmounting or disconnecting, but transfers still stall and fill dmesg with abundant errors fairly quickly.

(6) Using ehci-hcd, if you dd from the block device, everything works fine with a bs=xxx where xxx < 900. Go above 900, and the device disconnects.