CPU Temparature rises significantly when desktop is locked

Support
1

When I lock the desktop and the machine has been idling the CPU temperature is around 33degreesC. I lock the desktop and return after hours. After unlocking the desktop the CPU temperature is nearly 60degreesC. Immediately after unlocking the machine the temperature starts to return to the mid to low 30s. On occasion I have returned to the machine when it hasn’t really being doing anything and the machine is running hot with the internal fan going.

The machine is running MongoDB and MiniDLNA daemons but no DB or DLNA activity had been happening.

I would expect the machine to not use much CPU when idling?

System:
Kernel: 6.1.103-1-MANJARO arch: x86_64 bits: 64 compiler: gcc v: 14.1.1
Desktop: KDE Plasma v: 6.0.5 tk: Qt v: N/A wm: kwin_x11 dm: SDDM
Distro: Manjaro base: Arch Linux
Machine:
Type: Desktop Mobo: BESSTAR TECH model: UM350 serial:
Memory:
System RAM: total: 16 GiB available: 13.6 GiB used: 2.63 GiB (19.4%)
CPU:
Info: model: AMD Ryzen 5 3550H with Radeon Vega Mobile Gfx socket: FP5

2

Some background process has started when it sees the computer idle I guess. Maybe Baloo? You can try disabling or restricting what it indexes from System Settings → Search → File Search.

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3

Thanks, but this doesn’t seem to make any difference.

4

Well some process is using the cpu on the lock screen, just need to find out what it is. When you see it happening do CTRL+ALT+F3 for a new tty, login there and run top.

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5 
PID USER      PR  NI    VIRT    RES    SHR S  %CPU  %MEM     TIME+ COMMAN

2177 paul 20 0 3062276 308260 175740 R 63.5 2.2 9,26 kwin_x11
838 root 20 0 1362184 205988 134640 S 56.5 1.4 7,45 Xorg
2174 paul 20 0 1171412 100416 75620 S 17.6 0.7 128:30.24 ksmserver

These processes are using the CPU when the screen is locked and the KVM switch is looking at another device. I’m not sure why they would be using so much CPU when the machine is not really being used.

6

This is really quite a serious problem. Why does locking the workstation cause it to heat up and the fan to come on? Unlock the workstation and it goes back to normal. I like Manjaro but might have to switch to another Linux distribution.

7

This is Linux, there are always or at least mostly several ways to adjust something.

You can change so many stuff around your desktop…
Go in your system settings:

Screenlocking: Do some changes there. You can also remove screen lock complettly to get sure if your problem persists.

You can do additional adjustments around the Screenlocking there, if you sure your problem is related to this option.

Option2:
Colors & Themes>Global Theme>Remove Splash Screen (not sure if this has a impact) but it can’t hurt.

Also under Global Theme>Login Screen (SDDM) change the Theme there… to something that looks ugly :smile:

You can also download other Theme.

8

Then it is with the utmost certainty the result of the fact that you’re using a KVM switch. All of the processes you are listing are related to the user interface.

What you could try is switch to Wayland, but there’s no guarantee that it won’t be the same there.

9

It happened regardless of whether I switched to another machine using the KVM switch. It was something to do with locking the screen using X11.

I switched to Wayland and the issue is no longer happening.

Thank you.

10

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