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Asus ZenBook 13 (UX331UN) with Ubuntu: Battery drain while in suspend

When i got my shiny new ZenBook 13 UX331UN in July, i immediately wiped it and installed Ubuntu 18.04 (Bionic Beaver).

But I soon realized something was wrong with suspend: The laptop would go to sleep and over night the battery would either almost (10-ish percent) or completely drain, leaving the laptop completely powered off.

On other laptops the suspend state would eat about 5% charge per day, leaving you able to suspend around 3 weeks in theory, but something was using the battery in suspend here.

Here's the problem analysis:

Suspend your laptop. Wake it up again. Now check the output of

sudo journalctl | grep "PM: suspend" | tail -2

May 13 18:41:00 mex kernel: PM: suspend entry (s2idle)
May 13 20:52:36 mex kernel: PM: suspend exit

If you end up with 

Your laptop is only entering "s2idle" sleep (which is basicallynot saving much more than with blanking out screen and disabling the network). What we really want instead is the "deep" sleep.

You can also check

cat /sys/power/mem_sleep

which yields

[ s2idle] deep

meaning the s2idle state is active in standby, because it's written in brackets.

The permanent fix:

Edit your grub bootloader config to add a parameter to your Linux kernel when it boots. Type

sudo gedit /etc/default/grub

and replace the line GRUB_CMDLINE_LINUX_DEFAULT="quiet splash" with

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash mem_sleep_default=deep"

Save the file and exit. Now run

sudo update-grub && sudo reboot

To apply the changes and reboot. Test. Done.

IMPORTANT: If you now have troble waking your laptop up, DO NOT USE THE NVIDIA DRIVERS. They suck. Use noveau.

EDIT: The above works and is tested, but i now have the problem that the laptop won't resume when on battery. When it's on power supply it can resume. Any ideas!?

EDIT: You're  not alone: https://bugzilla.kernel.org/show_bug.cgi?id=201307 and https://askubuntu.com/questions/1071855/ubuntu-18-04-does-not-wake-up-from-suspend-on-asus-zenbook

Published inTechTalk


  1. griev04 griev04

    Hi, thank you for the post! I'm also facing the same issues with my UX331UN: have you been able to solve the problem that the laptop won’t resume when on battery?

  2. No, unfortunately not..

  3. Ingo Ingo

    I'm the author of the askubuntu question you are referring to. My notebook is a UX331U (no N) and your fix doesn't help. At first I thought you had spotted a crucial point with (i) the network adapter and (ii) the permanent grub entry rather than my echo deep > /sys/power/mem_sleep but neither of these helped. If you make any progress, with either battery or proper suspend, please post an update here. It would be greatly appreciated.

  4. Tommaso Tommaso

    Has anybody tried with the new kernel in Ubuntu 19.04?

  5. Yes, with the stock Kernel as well as with the Kernel from ukuu. Same problem

  6. Tommaso Tommaso

    FYI, there is a new BIOS update on the UX331UN, you might as well install it and do some new test:)

  7. Hi Tommaso, thank you for pointing that out. Indeed, I downloaded the June 2019 BIOS (308), but nothing has changed, all issues are still reproduceable.
    Did the Update fix something for you?

  8. Tommaso Tommaso

    It does not work on me either. Now I am using Manjaro Mate as it has bumblebee configured to work with Nvidia GPUs by default.

  9. Tommaso Tommaso

    I found the option of using DPMS for blanking the screen of the laptop under the power-manager option in Dconf. Since I don't use Ubuntu anymore but Manjaro, you might just give it a try as well!

  10. Anonymous Anonymous

    Hi Florian,
    Thanks for your post, I was experiencing same issue with UX333F and this has fixed the problem.

  11. Mike Mike

    Hi Florian,

    I have the same infamous UX331UN and I was experiencing the same issues as you. Thank you for the helpful post !
    I am running Linux Mint 19.1 ( Ubuntu 18.04 at base) and I had the same suspend issues as you. The modification in /etc/default/grub was invaluable but at times my laptop did not want to wake up at all . Lower in TLDR there is my solution that I have tested and seems to work for me. I get 20% battery drop in 13h55min while the laptop is in suspend mode.


    1. revert /etc/default/grub to what it was originally
    2. install kernel 5.2.11 ( I have used Ukuu Kernel Update Utility)
    3. Reboot and enjoy .

    Hope it helps,

  12. Mike Mike

    PS: The active GPU on my machine is Intel as I use the Nvidia GPU very rarely. The selection between the GPU's is made in the NVIDIA X Server Settings . I am not using the Nouveau drivers but the Nvidia driver version 430.26-0ubuntu0.18.04.2 .

  13. Henry Henry

    Hi Florian,

    Thanks for the useful post. I have the same issue and I've been following the Bug report, hoping someday this will be fixed…

    On a slightly related note. I noticed that, on Windows, the laptop's fans make quite a good amount of noise on any high-intensity task, but I've never heard them spinning as much in Linux (Manjaro), even when I'm running intensive IO/CPU tasks (like, for example, loading and indexing a 16 Gb codebase using IntelliJ IDEA). When I tried `sensors-detect`, only the `coretemp` module shows as available and, to this day, I haven't found a way for the OS to recognize (thus I could monitor) the fans.

    Have you noticed this, if not, did you do anything special on your setup?

    My silly hypothesis is that this is making the OS to not work as hard as it does on Windows, perhaps to prevent overheating? Dunno, but I feel that this laptop is powerful and yet it performs really slow on high-intensity tasks when in Linux.

    Did you manage to recognize the fans? Any help would be highly appreciated.

    Thanks in advance, and again, great blog post, very useful!

  14. Whit Whit

    Thanks! With a UX331FA and Ubuntu 19.10, and the same problem with suspend eating too much battery overnight, this advice on setting "deep" appears still good — but I haven't tested it overnight. There's no problem waking from suspend in either setting.

  15. Hey Whit, that's interesting. I do have Problems waking up from deep sleep. What kernel are you using? ( uname -a ) Thx

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