For those using an HP 2140, upgrading the BIOS firmware should solve the problem (https://bugs.launchpad.net/ubuntu/+source/linux/+bug/338707/comments/5).
For those using an HP 2140, upgrading the BIOS firmware should solve the problem (https:/ /bugs.launchpad .net/ubuntu/ +source/ linux/+ bug/338707/ comments/ 5).