Ubuntu won’t suspend using TLP

I have installed TLP on my notebook with Ubuntu 14.04 to extend my battery life. Before using TLP I had laptop-mode-tools and pm-utils installed with some custom scripts. Both extended my battery life by over 100%, however TLP almost didn’t need any configuration to achieve this.

The problem

However, I got one problem after installing TLP: Ubuntu wouldn’t suspend anymore. I was sure that it was still working just a day ago. If I click suspend, the screen goes blank for just a second and then I’m at the lock screen. The power LED doesn’t turn off, it just looks as if I accidentally clicked the log out button.

I’ve tried many workarounds, like this one on Ask Ubuntu. All other workarounds were nearly the same, and they all didn’t work for me.

So I started trying to fix the issue by myself.

If I executed echo mem > /sys/power/state or echo disk > /sys/power/state my notebook would suspend and resume as it should. So the suspend itself was working, but something was interrupting the suspend process before the notebook would actually suspend. It couldn’t be a wakeup call of any device, because I already disabled all wakeup devices.

I checked /var/log/syslog and /var/log/kern.log but they didn’t contain any useful information. They only told me that my WiFi adapter was disconnecting to prepare my notebook for the suspend, to immediately connect again.

Then I checked /var/log/pm-suspend.log. At first it looked all okay to me. Then I saw the following:

Running hook /etc/pm/sleep.d/10-laptop-mode-tools suspend suspend:
/etc/pm/sleep.d/10-laptop-mode-tools: 6: /etc/pm/sleep.d/10-laptop-mode-tools: /etc/init.d/laptop-mode: not found
/etc/pm/sleep.d/10-laptop-mode-tools suspend suspend: Returned exit code 127.

Wed Apr 23 15:27:19 CEST 2014: Inhibit found, will not perform suspend
Wed Apr 23 15:27:19 CEST 2014: Running hooks for resume

It couldn’t find laptop-mode-tools anymore, which I had to remove in order to use TLP, so it just aborted the whole suspend process.

The solution

After removing /etc/pm/sleep.d/10-laptop-mode-tools everything was working as it should again.

Note: I recommend you to make a backup of the script first (copy it to your Documents directory using sudo cp /etc/pm/sleep.d/10-laptop-mode-tools ~/Documents/) so you can always copy it back if you have to.

So, if you’re having this issue too, just execute sudo rm /etc/pm/sleep.d/10-laptop-mode-tools.