I also have the MX900, when I plug in the Logitech Bluetooth Wireless Hug, I see the following in /var/log/messages:
Jul 21 20:00:39 localhost kernel: [17190561.104000] usb 1-1.2: new full speed USB device using uhci_hcd and address 10 uname -a output: Linux gimli 2.6.15-26-386 #1 PREEMPT Mon Jul 17 19:52:53 UTC 2006 i686 GNU/Linux -- Bluetooth mouse not correctly recognized https://launchpad.net/bugs/35983 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
