Comment 13 for bug 1315425

Hello i have the same probleme .

I found a work around i uninstall TLP

sudo apt-get remove tlp

it seems tlp disable some feature in shutdown process see /var/log/pm-powersave.log

Running hook /etc/pm/power.d/pcie_aspm false:
Notice: '/usr/lib/pm-utils/power.d/pcie_aspm' disabled by TLP.
/etc/pm/power.d/pcie_aspm false: success.

Running hook /etc/pm/power.d/sata_alpm false:
Notice: '/usr/lib/pm-utils/power.d/sata_alpm' disabled by TLP.
/etc/pm/power.d/sata_alpm false: success.

Running hook /etc/pm/power.d/sched-powersave false:
Notice: '/usr/lib/pm-utils/power.d/sched-powersave' disabled by TLP.
/etc/pm/power.d/sched-powersave false: success.

Running hook /etc/pm/power.d/usb_bluetooth false:
Notice: '/usr/lib/pm-utils/power.d/usb_bluetooth' disabled by TLP.
/etc/pm/power.d/usb_bluetooth false: success.

Running hook /etc/pm/power.d/wireless false:
Notice: '/usr/lib/pm-utils/power.d/wireless' disabled by TLP.
/etc/pm/power.d/wireless false: success.

Running hook /etc/pm/power.d/xfs_buffer false:
Notice: '/usr/lib/pm-utils/power.d/xfs_buffer' disabled by TLP.
/etc/pm/power.d/xfs_buffer false: success.

 now it works normally