My Dell laptop running Ubuntu Linux 11.10 hangs reliably while shutting down for a reboot, but when I shutdown, it will complete successfully. How do I diagnose this? I don't know what log files I should go to in order to observe the relevant system events during the time of reboot/shutdown.
shutdown -r now; # This results in a hang during the Ubuntu shutdown splash.
shutdown -hP now; # This will work perfectly and quickly.