As a last resort I upgraded the bios/uefi of the mainboard (B85M-G BIOS 0410 -> B85M-G BIOS 0703) and now it works.
Funny though, that 3.2 managed to circumvent whatever the bios messed up. Anyway, sorry for the noise. ** Changed in: linux (Ubuntu) Status: Triaged => Invalid -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1254261 Title: xhci regression: usb 3.0 hdd disconnects immediately To manage notifications about this bug go to: https://bugs.launchpad.net/linux/+bug/1254261/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs