I'm experiencing the same issue on a Dell Latitude C640. The workaround works, sort of. The X-server doesn't crash but the DPMS remains off. Only by remotely accessing the macheine, issuing a xset dpms force on, makes the machine come alive again. (Short of the three-finger-salute)
-- Xorg exits when it receives an ACPI button/lid event https://launchpad.net/bugs/61746 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs