Ubuntu 7.04/Issues/Hang on reboot
Description: System may hang while performing a reboot or shutdown
Systems Affected: Dimension E520n, XPS 410n
Impact: System hang
Workaround: Pass the "reboot=b" switch to the kernel at boot time. This workaround is already scripted in the factory preloaded image.
Fix: The kernel that has this fix will be available in a future Ubuntu 7.04 update online.