Dell Studio 1569 Cannot Shutdown in Ubuntu 11.10 or 12.04

I fixed the problem.

Dell's ACPI support is incredibly bad.

Because of this, you have to open up the grub configuration file and add the property acpi=force.

gksu gedit /etc/default/grub

Once there, find where it says, GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"

Change this to read:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi=force"

Save it, then run this command to update your grub configuration.

sudo update-grub

Finally, reboot, and your machine should now be able to shutdown and reboot without correctly!

If you are using Laptop-mode-tools, you might should try removing it.

I had a similar problem: whenever I tried to shut down when running on battery, everything seems to go normally, until it says "will now halt" and then "power down" after which my laptop doesn't shut down as it normally would, but nothing happens anymore and I have to press the start-up button for 6 seconds to shut it down.

This problem however disappeared after removing laptop-mode-tools. (the first shut down after removal was still problematic)

I don't know what exactly caused the problem, nor how to fix it with lmt still installed (there has to be a way I think, but I'm quite new to GNU/Linux so I don't have a clue how to. The fixes I found for similar problems didn't solve mine.)

I tried to add INIT_HALT=POWEROFF to /etc/default/halt and that solved my problem for what concerns both halting and rebooting of the machine.