Reboot after shutdown (Ubuntu 14.04 (also 12.04); Dell latitude E7440)

I have a rather serious shutdown/reboot issue with my Ubuntu OS on my brand new Dell latitude E7440 netbook. The issue does not seem to depend on the OS version: it occurs with 12.04, 13.10 and now with 14.04. I've waited for the new LTS in the hope that it would solve my problem, but that is not the case.

After shutting down my ubuntu, my laptop reboots about two seconds after shutdown. I've tried many things to solve it, but none of them did the job. I have the 64 bit version of 14.04 installed and boot in legacy boot mode with secure boot disabled. The behavior is independent from a power cable/usb device/ethernet cable being plugged in. Strange enough, however, it does sometimes stay powered off after being used for several hours...

I know there have been several treats concerning shutdown/reboot issues, but none of them provides an answer to my specific case. I ran diagnostics in the BIOS to recover any potential hardware problems, but there were none. If you have an answer or even a clue on how to solve this issue, it will be highly appreciated! Thanks in advance!

Solution 1:

I experienced exactly the same problem on my new computer Intel i5-4440 processor and Intel DB85FL motherboard (4th Gen). First I faced this problem with Ubuntu 13.10. and subsequently after upgrading to 14.04 LTS.

I did the following recently to solve this problem of SHUTDOWN and automatic REBOOT again withing a second or two.

I have Intel Visual BIOS. On power up I pressed F2 > POWER > Wake On LAN from S4/S5.

This has 3 options. 1. Stay Off, 2. Power on - Normal Boot, and 3. Power on - PXE Boot. My computer was set to #2, which was making it automatically REBOOT after SHUTDOWN. I now changed to #1 option mentioned above. Now it is okay.

Hope this would work for you as well. Best wishes.

Solution 2:

I also faced the same case on my Acer Aspire E1-470G using Ubuntu 14.04. These steps worked for me.

1. Type in terminal

   sudo nano /etc/default/grub
   

   then find a line

   GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
   

   Modify it to

   GRUB_CMDLINE_LINUX_DEFAULT="quiet splash" acpi=force apm=power_off
   

2. Type in terminal sudo nano /etc/grub/modules then add apm power_off=1 under line lp. Save and close the terminal.

3. Update the GRUB

   sudo update-grub
   

Solution 3:

I had the same problem with my new intel motherboard and core i5 processor, Ubuntu 14.04.1 64bit OS. I tried to disable wakeup from LAN from bios and did not get any success.

Then I modified

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"

to

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash" acpi=force apm=power_off

Still no success.

One of my colleagues suggested that, though mine was a desktop PC, I should install laptop-mode-tools, and surprisingly it worked!