Comment 4 for bug 966248

on a vostro 3550 with single usb3 port, after plugging in portable usb3 drive it IS recognized. right after loading a CD into drive, usb3 portable drive is no longer detected by ubuntu. like it was disconnected.

this can be one more thing that you could test with the newer kernel, Solomon, to see if the port cuts out unexpectedly.

does not happen in msWin.
have not tried the upstream kernel yet.
current updates on the 12.04 beta.