ThinkPad T400s randomly reboots when waking up from suspend

boarim · 2026-03-17 07:17:32

I have this issue for quite a while now, but never managed to find the root cause. I don’t really know where to look for to be honest. The laptop is a ThinkPad T400s running Libreboot, and the linux-hardened kernel from the official repositories. I don’t have a swap partition since I have more than enough RAM (8GB) and I am in a Wayland session (sway).

When I close the lid, my laptop goes to suspend mode (not hibernation). When I re-open the lid, from time to time, the screen stays black for few seconds, and then the PC automatically reboots. It’s quite annoying, especially at work, since it appears to be random.

I have searched the wiki, but I couldn’t find a relevant section about my problem.

What should I look for first? Libreboot issue? Kernel issue?

seth · 2026-03-17 08:06:38

PC automatically reboots

* overheated (unlikely)
* underpowered (more likely)
* broken CPU
* bad RAM
* ACPI issue (I assume you're not dual booting, but could indeed be libreboot)

There's probably no journal coverage after the wakeup, but for a general oversight please post your complete system journal for and affected boot, eg.

sudo journalctl -b -1 | curl -F 'file=@-' 0x0.st

for the previous ("-1") one.
If there's HW issues they *might* show up as MCE errors in the journal of the subsequent reboot.

boarim · 2026-03-22 07:52:55

Sorry for the delay and thank you for your reply. I was waiting for a new occurrence of the problem to happen to post my message. I got the issue after having left the laptop on sleep while on battery the whole night. When I opened the lid this morning, I got the automatic reboot (battery level was 58% after reboot).

I didn’t get why I need to pipe curl to filter the logs. Here’s what I got (I’m part of wheel so I didn’t need to use sudo):

$ journalctl -b -1 | curl -F 'file=@-' 0x0.st
<html>
<head><title>301 Moved Permanently</title></head>
<body>
<center><h1>301 Moved Permanently</h1></center>
<hr><center>nginx</center>
</body>
</html>

What did I do wrong? I also exported the full log as a text file for further filtering.

Last edited by boarim (2026-03-22 07:53:36)

seth · 2026-03-22 08:42:02

Nothing, 0x0.st no longer automatically forwards to https

journalctl -b -1 | curl -F 'file=@-' https://0x0.st

nb. that this is NOT a "filter", you're piping the output into curl which uploads it to 0x0.st, you get a url and can post that.

boarim · 2026-03-22 14:55:44

Oh I see. Now I got it (and I didn’t see that you even had a link to the wiki in your signature sorry).

I’m not comfortable uploading the full log of my system which contains sensitive information though (like IP and MAC addresses, usernames, etc.). Is there a way for me to hide these, or at least to upload only relevant parts of the log?

seth · 2026-03-22 15:17:09

You can redirect the journal output into a file and edit that.
LAN IPv4 aren't sensitive, https://en.wikipedia.org/wiki/Private_network
MACs are trackable (if you post them across the internet) but of no value outside your proximity (where the NICs yell them into the air)
You username is "boarim"?

Whatever you do, make sure to *pseudonymize* the information, ie. maintain the general structure and uniquely map data, ie "AA:AA" => "XX:XX", "BB.BB" => "YY.YY", not everything I want to hide is now "xxx"

boarim · 2026-03-29 16:18:08

Sorry again for the late reply.

I pseudonymized some information and uploaded the log to paste.c-net.org because 0x0.st disabled uploads (they got too much AI botnet spam for the past few months).

Hope this can help.

seth · 2026-03-29 21:25:52

Log ends with entering the sleep, the system doesn't wake up or doesn't manage to write anything before it reboots.
Nothing really flares up before.
There's an external drive (HDD, WD My Passport) that gets powered off and disconnected

Mar 21 17:10:11 katana udisksd[1389]: Powered off /dev/sdc - successfully wrote to sysfs path /sys/devices/pci0000:00/0000:00:1a.7/usb4/4-1/remove
Mar 21 17:10:11 katana kernel: usb 4-1: USB disconnect, device number 7

Despite this being followed by another successful S3 cycle, is it physically disconnected (as well - the disconnect happens so quick after the power-off that it looks like it was logically ejected at that point)

Is the fingerprint reader a dongle?

boarim · 2026-03-30 06:11:16

Is the fingerprint reader a dongle?

No, it’s integrated in the laptop, in the palm rest. I’ve never used nor installed any package to activate it.

There's an external drive (HDD, WD My Passport) that gets powered off and disconnected

At that particular time I had the drive plugged to the laptop, but I had the issue multiple times in the past when it wasn’t connected, so it shouldn’t be relevant to the problem.

Last edited by boarim (2026-03-30 06:11:45)

seth · 2026-03-30 13:42:37

Yes "should" …
Because of the list in #2 and if you can eg. put RAM and CPU under stress (memtest and for the latter maybe corecycling) w/o causing any problems some additional power draw would be the most likely contender (bogus ACPI likely would be more deterministic)
Can you remember to strip all external devices from the system before sleeping and see whether you run into a reboot again?

Simple homebrew corecycler: https://bbs.archlinux.org/viewtopic.php … 9#p2260219

boarim · 2026-04-04 06:26:12

I haven’t put RAM and CPU under stress yet, but I just had another reboot after leaving the laptop sleeping all night. No external devices attached this time.

It seems to happen when battery level goes down a certain value (I had 30% left when the reboot occurred).

seth · 2026-04-04 09:06:38

Mar 21 08:22:31 archlinux kernel: smpboot: CPU0: Intel(R) Core(TM)2 Duo CPU     P9600  @ 2.53GHz (family: 0x6, model: 0x17, stepping: 0xa)

The device is a bit elderly, I assume?
Original battery?

tail /sys/class/power_supply/BAT*/*

The reasonable assumption is that the drained battery can no longer provide sufficient voltage - the only fixes for that are
1. new battery
2. a power chord

boarim · 2026-04-04 10:15:22

The device is a bit elderly, I assume?
Original battery?

Yes made in 2009 with original battery.

Here is what I got:

$ tail /sys/class/power_supply/BAT*/*
==> /sys/class/power_supply/BAT0/alarm <==
0

==> /sys/class/power_supply/BAT0/capacity <==
77

==> /sys/class/power_supply/BAT0/capacity_level <==
Normal

==> /sys/class/power_supply/BAT0/charge_behaviour <==
[auto]

==> /sys/class/power_supply/BAT0/charge_control_end_threshold <==
90

==> /sys/class/power_supply/BAT0/charge_control_start_threshold <==
85

==> /sys/class/power_supply/BAT0/charge_start_threshold <==
85

==> /sys/class/power_supply/BAT0/charge_stop_threshold <==
90

==> /sys/class/power_supply/BAT0/cycle_count <==
0

==> /sys/class/power_supply/BAT0/device <==
tail: error reading '/sys/class/power_supply/BAT0/device': Is a directory

==> /sys/class/power_supply/BAT0/energy_full <==
25260000

==> /sys/class/power_supply/BAT0/energy_full_design <==
43290000

==> /sys/class/power_supply/BAT0/energy_now <==
19470000

==> /sys/class/power_supply/BAT0/extensions <==
tail: error reading '/sys/class/power_supply/BAT0/extensions': Is a directory

==> /sys/class/power_supply/BAT0/hwmon2 <==
tail: error reading '/sys/class/power_supply/BAT0/hwmon2': Is a directory

==> /sys/class/power_supply/BAT0/manufacturer <==
Panasonic

==> /sys/class/power_supply/BAT0/model_name <==
42T4833

==> /sys/class/power_supply/BAT0/power <==
tail: error reading '/sys/class/power_supply/BAT0/power': Is a directory

==> /sys/class/power_supply/BAT0/power_now <==
12773000

==> /sys/class/power_supply/BAT0/present <==
1

==> /sys/class/power_supply/BAT0/serial_number <==
 9348

==> /sys/class/power_supply/BAT0/status <==
Discharging

==> /sys/class/power_supply/BAT0/subsystem <==
tail: error reading '/sys/class/power_supply/BAT0/subsystem': Is a directory

==> /sys/class/power_supply/BAT0/technology <==
Li-ion

==> /sys/class/power_supply/BAT0/type <==
Battery

==> /sys/class/power_supply/BAT0/uevent <==
POWER_SUPPLY_POWER_NOW=12773000
POWER_SUPPLY_ENERGY_FULL_DESIGN=43290000
POWER_SUPPLY_ENERGY_FULL=25260000
POWER_SUPPLY_ENERGY_NOW=19470000
POWER_SUPPLY_CAPACITY=77
POWER_SUPPLY_CAPACITY_LEVEL=Normal
POWER_SUPPLY_TYPE=Battery
POWER_SUPPLY_MODEL_NAME=42T4833
POWER_SUPPLY_MANUFACTURER=Panasonic
POWER_SUPPLY_SERIAL_NUMBER= 9348

==> /sys/class/power_supply/BAT0/voltage_min_design <==
11100000

==> /sys/class/power_supply/BAT0/voltage_now <==
11644000

I was thinking of changing the battery eventually. I’m just a little bit reluctant buying from a Chinese seller on eBay.

The reasonable assumption is that the drained battery can no longer provide sufficient voltage

That would make sense since I’ve yet to experience the issue when the laptop is plugged.

seth · 2026-04-04 14:23:07

The battery is down to 58.3% of its original capacity (unless you're using some preservation methods that artificially limit the charge - what's less likely for a 2009 model)

==> /sys/class/power_supply/BAT0/voltage_min_design <==
11100000

==> /sys/class/power_supply/BAT0/voltage_now <==
11644000

Check those values again when the battery is < 30%, but it's already very likely that this is the cause of the behavior.

boarim · Yesterday 05:52:42

Well, I’m giving up on this.

Lately, I’ve been plugged to an external monitor, so the laptop isn’t running on battery. Nevertheless, two days in a row, after having left the laptop sleep all night, I’ve the reboot happening when waking up the system in the morning.

Arch Linux

#1 2026-03-17 07:17:32

ThinkPad T400s randomly reboots when waking up from suspend

#2 2026-03-17 08:06:38

Re: ThinkPad T400s randomly reboots when waking up from suspend

#3 2026-03-22 07:52:55

Re: ThinkPad T400s randomly reboots when waking up from suspend

#4 2026-03-22 08:42:02

Re: ThinkPad T400s randomly reboots when waking up from suspend

#5 2026-03-22 14:55:44

Re: ThinkPad T400s randomly reboots when waking up from suspend

#6 2026-03-22 15:17:09

Re: ThinkPad T400s randomly reboots when waking up from suspend

#7 2026-03-29 16:18:08

Re: ThinkPad T400s randomly reboots when waking up from suspend

#8 2026-03-29 21:25:52

Re: ThinkPad T400s randomly reboots when waking up from suspend

#9 2026-03-30 06:11:16

Re: ThinkPad T400s randomly reboots when waking up from suspend

#10 2026-03-30 13:42:37

Re: ThinkPad T400s randomly reboots when waking up from suspend

#11 2026-04-04 06:26:12

Re: ThinkPad T400s randomly reboots when waking up from suspend

#12 2026-04-04 09:06:38

Re: ThinkPad T400s randomly reboots when waking up from suspend

#13 2026-04-04 10:15:22

Re: ThinkPad T400s randomly reboots when waking up from suspend

#14 2026-04-04 14:23:07

Re: ThinkPad T400s randomly reboots when waking up from suspend

#15 Yesterday 05:52:42

Re: ThinkPad T400s randomly reboots when waking up from suspend

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