Sleep mode drains battery very fast

Question

Battery drains in about 10 hours when the computer is asleep with Ubuntu 18.04, it is a lenovo y520 (7700hq, 1060 with bumblebee).
When I tested no USB devices were plugged in, actually nothing was plugged in.
The sleep mode is s2 - deep. I am not interested in hibernation (it is quite slow and takes a lot of space).
In windows and Mac OS (hackintosh) sleep mode uses 1 or 2% of battery in a day.

Solution 1

After resuming from suspend, use this command in the terminal:

journalctl -b | grep -i "should not be sleeping"

If you see this:

Oct 21 07:20:18 alien kernel:  cache: parent cpu1 should not be sleeping
Oct 21 07:20:18 alien kernel:  cache: parent cpu2 should not be sleeping
Oct 21 07:20:18 alien kernel:  cache: parent cpu3 should not be sleeping
Oct 21 07:20:18 alien kernel:  cache: parent cpu4 should not be sleeping
Oct 21 07:20:18 alien kernel:  cache: parent cpu5 should not be sleeping
Oct 21 07:20:18 alien kernel:  cache: parent cpu6 should not be sleeping
Oct 21 07:20:18 alien kernel:  cache: parent cpu7 should not be sleeping

It could mean when you suspended the CPU's were not put to sleep as per his bounty Q&A a couple of years ago: systemd suspends system but upon resume kernel then enters sleep and wake-up

If so, I'm sad to report the problem persists to this day on my newest laptop just as it did on that older laptop.

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Problem since 2012?

This old email chain: Re: Kernel stops at "PM: Preparing system for mem sleep", never makes it to "Freezing user space processes ... " has a similar problem.

From my log file today:

Oct 21 13:48:15 alien kernel: PM: Preparing system for sleep (mem)
Oct 21 13:48:16 alien acpid[964]: client 1171[0:0] has disconnected
Oct 21 13:48:32 alien kernel: Freezing user space processes ... (elapsed 0.003 seconds) done.

• Line 1 is normal
• Line 2 is abnormal and linked to old X11 crash bugs
• Line 3 is occurs after resuming but should have happened as part of suspend.

Some other interesting points is it often takes 5 to 8 seconds to suspend when it should be about 1 second. This bug is reported in many places too.

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If you don't have the same problem in the previous sections and, your laptop stays warm when suspended, then your fix maybe here: Ubuntu 18.04 - Dell XPS13 9370 no longer suspends on lid close

Solution 2

On my old computer, I solved my suspend issues by adjusting some settings in the motherboard BIOS.

For my hardware:

On the "Advanced" page in BIOS under "CPU configuration", I set "Enhanced Alt State" to ENABLED, and under "ACPI Settings" , I set "Suspend to RAM" to AUTO and "ACPI table" to ENABLED.

After I made these changes, I could suspend my PC.

Note: BIOS settings and motherboard firmware vary by manufacturer and model

Comments

[George]

Yep, I get the same output :|

[George]

Is it the same thing for 16.04 ?

[WinEunuuchs2Unix]

Yes. The logs above were generated this morning under Ubuntu 16.04.5 LTS.

[George]

Maybe you saw this coming, but what about 14.04 ?

[WinEunuuchs2Unix]

According to the first link, I believe 14.04 works OK but can't confirm it today as that laptop needs some TLC to get boot working again. However with email chain I discovered with kernel developers and just posted in this answer it may have been broken for some in Ubuntu 14.04 all the way back to Ubuntu 12.04.

[George]

Just so I know, does this mean there's no difference between sleep and idle for the cpu or does it chill out a bit ?

[George]

Hey, umm, more great news, I tried switching to windows for a day, then I find out not even windows' sleep is working anymore, is it related to linux, (bootloader more specifically)

[George]

I've done a frsh install of windows, sleep behaves now just like ubuntu, it;s ridiculous. How do I get rid of this...?

[Elder Geek]

@WinEunuuchs2Unix Do you suppose out-of-order-execution could be to blame for askubuntu.com/questions/828486/… ? I updated my answer there with a way you could test that.

[WinEunuuchs2Unix]

@ElderGeek I quickly read your answer revisions. I'm not sure that's the culprit but am hoping the bug report filed yeseterday will give answers: bugs.launchpad.net/ubuntu/+source/linux-signed-hwe/+bug/1825‌​636