Subject: LXQt desktop periodically becomes unresponsive on newish AMD Thinkpad P16s

Hi,

I have a fresh installation of Trixie with LXQt on a P16s Gen4 AMD. Periodically (more than once per hour), the whole desktop becomes unresponsive. Windows can't be moved or typed into and the clock doesn't update.

The mouse pointer still moves, the caps lock LED still operates, audio continues to work (vlc playing through pipewire) and I can change virtual console using <Ctrl><Alt><F1> etc and type into that virtual console.

<Fn><Backspace> still puts the computer to sleep, and after waking up it can be unlocked and functions normally. This is currently the only method I have found to continue working.

Restarting xfwm4 from another virtual console does NOT help. The problem
goes away after restarting lightdm, but this is obviously not an adequate solution.

Volume and screen brightness adjustments using the function keys still work. Keypresses and and mouseclicks entered before suspending seem to be queued
and processed after waking up and unlocking. This feels like it should be a clue to what is getting stuck.

I haven't managed to find any relevant log messages in dmesg, syslog or Xorg.0.log.

linux-image-amd64, firmware-linux, mesa and fwupd are from backports. fwupd says the BIOS is up to date, having successfully applied one update. It's
been doing this since before Christmas, across several kernel versions.

Any ideas for what's going on or how to fix it, please?

Thanks,

Roger

--- PyGate Linux v1.5.13
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

Subject: Re: LXQt desktop periodically becomes unresponsive on newish AMD Thinkpad P16s

On 2026-03-25, Roger Lynn wrote:

Any ideas for what's going on or how to fix it, please?

Try to keep a top (package procps) running to find if it is a
memory or cpu problem

--- PyGate Linux v1.5.13
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

Subject: Re: Re: LXQt desktop periodically becomes unresponsive on newish AMD Thinkpad P16s

On 26 Mar 2026, Michel Verdier wrote:

On 2026-03-25, Roger Lynn wrote:

Any ideas for what's going on or how to fix it, please?

Try to keep a top (package procps) running to find if it is a
memory or cpu problem

There is nothing using significant amounts of CPU or memory, confirmed in another virtual console. The machine has not yet been heavily used and the hangs seem unrelated to how much is running, sometimes occurring with
nothing more than aptitude running in an xterm.

Thanks,

Roger

--- PyGate Linux v1.5.13
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

Subject: Re: Re: LXQt desktop periodically becomes unresponsive on newish AMD Thinkpad P16s

On 3/25/26 6:07 PM, Roger Lynn wrote:

Restarting xfwm4 from another virtual console does NOT help. The
problem goes away after restarting lightdm, but this is obviously not
an adequate solution.

It's not an adequate solution, but it *does* hint at where the problem
might be: lightdm.

I think this probably fixes it because it restarts the xserver, so
everything gets reset.

I haven't managed to find any relevant log messages in dmesg, syslog or
Xorg.0.log.

Is there anything in `/var/log/lightdm/` that might have more
information? You can also check the journal for hints:

`$ journalctl -u lightdm.service`

The only things in there seem to relate to unlocking after putting the
computer into standby and waking it up again or switching VT.

But, having said in another email just now that it doesn't seem to be caused
by system load, it might happen more often when using an xterm.

Thanks,

Roger

--- PyGate Linux v1.5.13
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

Subject: Re: LXQt desktop periodically becomes unresponsive on newish AMD Thinkpad P16s

Apologies, the Mail-Followup-To header got messed up on my previous email,
so Pocket's reply was not copied to the list.

Pocket wrote on 27/03/2026 00:55:

On 3/26/26 8:11 PM, Roger Lynn wrote:

On 26 Mar 2026, Michel Verdier wrote:

On 2026-03-25, Roger Lynn wrote:

Any ideas for what's going on or how to fix it, please?

Try to keep a top (package procps) running to find if it is a
memory or cpu problem

There is nothing using significant amounts of CPU or memory, confirmed in
another virtual console. The machine has not yet been heavily used and the >> hangs seem unrelated to how much is running, sometimes occurring with
nothing more than aptitude running in an xterm.

I have seen this before on a Raspberry pi 5

My research has found it is PCManFM-Qt, which is the file manager

I have not figured out exactly what causes this other than it

crashes and the desktop become unresponsive until it "resets"

itsÿself and restarts.ÿ It is linked to some type if disk io, like

the drive is not responsive and file manager disappears.

Thanks for the suggestion. So far I have made very little use of the file manager, but I see that the process is running, so I will look at that next time it happens.

Roger

--- PyGate Linux v1.5.13
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

Subject: Re: LXQt desktop periodically becomes unresponsive on newish AMD Thinkpad P16s

On 3/26/26 7:11 PM, Roger Lynn wrote:

There is nothing using significant amounts of CPU or memory, confirmed in another virtual console. The machine has not yet been heavily used and the hangs seem unrelated to how much is running, sometimes occurring with
nothing more than aptitude running in an xterm.

Thanks,

Roger

On the subject of system load I think of one more thing to check: what
do the load average stats look like? If load average increases beyond
the number of available cpu threads you will have freeze-ups. Just today
I was working with a system I had running at 75% cpu load, then I
noticed load average climbing out of control, so I quickly adjusted the
load before it's to late...

nwe@desk:~$ top
top - 20:36:43 upÿ 1:43,ÿ 1 user,ÿ load average: 0.11, 0.14, 0.22

My 1 minute load average here is at 0.11 which means my 8 thread cpu is
just idling. If it were to increase near or beyond 8.00 I would say my
cpu is overloaded even if it is not at 100% load.

--- PyGate Linux v1.5.13
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

Subject: Re: LXQt desktop periodically becomes unresponsive on newish AMD Thinkpad P16s

On 3/26/26 8:07 PM, Roger Lynn wrote:

Pocket wrote on 27/03/2026 00:55:

I have seen this before on a Raspberry pi 5

My research has found it is PCManFM-Qt, which is the file manager

I have not figured out exactly what causes this other than it

crashes and the desktop become unresponsive until it "resets"

its?self and restarts.? It is linked to some type if disk io, like

the drive is not responsive and file manager disappears.

Thanks

That makes sense. Here I'm running XFCE4 and thunar.
Thunar freezes for me when file any io hangs. Only it does not seem to
affect most other apps on my system.
Another idea: do you have the sensors package installed? If yes, check
whether any high temperatures are being reported?


--- PyGate Linux v1.5.13
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)