| From: Russell Reiter via talk <talk@gtalug.org> | So, on further reflection, it looks like the most current | Ubuntu spinsare hardwired to always use XHCI. This seems to me to be | atransitional problem in upgrading from usb 2.0 to 3.0. If you are able | to change this setting with your MB, you might trydisabling XHCI in | bios. This should force the system to EHCI and mightresolve what I'm | seeing presented as endpoint block errors in bulktransfers. Might also | resolve your USB serial issues. Hope this helps. This sounds crazy. After all USB 3.0 can do anything USB 2 can do. But it isn't. My SnapScan won't work on a USB 3 port with Linux. But it will work with a USB 2 port. Known problem. Surely a kernel bug but no kernel hacker has stepped up to fix it.