Arch Linux

0BADC0DE

Member

From: Regnum Utriusque Siciliae

Registered: 2018-02-21

Posts: 268

Second monitor not working anymore

Hi all. This is my environment:
Kernel Version : 6.0.9.zen1-1
Plasma Version : 5.26.3-1
KDE Version : 22.08.3-1
Frameworks Version : 5.100.0-1
Qt5 Version : 5.15.7+kde+r6-1
Wayland Version : 1.21.0-1
Mesa Version : 22.2.3-1

Since a couple of day my second monitor doesn't work anymore. That is, the monitor works but I cannot get the output to it.
I have tried both the built-in HDMI socket and my usual USB-C docking station.
Both used to work fine so far.
The docking station works for everything else (keyboard, mouse, Ethernet and power delivery) just fine.
I would exclude a hardware problem as it would require two broken things at the same time: the built-in HDMI socket *and* the USB-C port.

I think that some of the updated packages just broke this feature.
I see that maybe my latest upgrade for libxrandr (1.5.2-5 -> 1.5.3-1) could be the culprit.
Downgrading libxrandr didn't help.
I can also see that there could be two more possible culprits:
qt5-base (5.15.7+kde+r174-1 -> 5.15.7+kde+r175-1) and linux-firmware (20221109.60310c2-1 -> 20221109.60310c2-2).

At the moment I have this:

$ xrandr --listmonitors
Monitors: 1
 0: +*XWAYLAND0 1920/310x1080/170+0+0  XWAYLAND0

Any hint?

Last edited by 0BADC0DE (2022-11-23 11:02:28)

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V1del

Forum Moderator

Registered: 2012-10-16

Posts: 21,627

Re: Second monitor not working anymore

You'd need to check kscreen/KDE system settings on whether the monitor is simply disabled for some reason, xrandr can't actually manipulate your real monitors on Wayland. From your list the linux-firmware change seems potentially most likely, though all this should have done is drop some arm firmware from the marvell subpackage so this is also quite unlikely. Was there no kernel update involved between then and now?

Last edited by V1del (2022-11-23 14:56:35)

0BADC0DE

Member

From: Regnum Utriusque Siciliae

Registered: 2018-02-21

Posts: 268

Re: Second monitor not working anymore

It seems no kernel update happened soon before the issue. On 21st it was working. On 22 it wasn't any more.

I didn't change any setting, though.

Last edited by 0BADC0DE (2022-11-23 15:04:48)

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Maybe Computers Will Never Become As Intelligent
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seth

Member

Registered: 2012-09-03

Posts: 50,929

Re: Second monitor not working anymore

I didn't change any setting, though.

Did you mayhaps run on X11 before? Does the configuration work as expected on X11?

Edit: before you try, check the timestamp of the last X11 log to answer the first question.

Last edited by seth (2022-11-23 15:06:58)

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0BADC0DE

Member

From: Regnum Utriusque Siciliae

Registered: 2018-02-21

Posts: 268

Re: Second monitor not working anymore

My latest X11 run dates back to 2022-07-25, 4 months ago.
I would exclude any interference from X11.

Today I have news. And wierd ones.
In the past 2 days I've been working in the office with the very same brand/model USB docking station (Lenovo ThinkPad USB-C Dock Gen2 40AS) and same cabling.
For two days I have tried two different external HDMI monitors and two different docking stations (same brand/model as above) with no luck.
The built-in HDMI socket seemed not to work ("No HDMI input" from the external monitors).
Today I am back at home and everything works:

$ xrandr --listmonitors
Monitors: 2
 0: +*XWAYLAND1 1920/530x1080/300+1920+0  XWAYLAND1
 1: +XWAYLAND0 1920/310x1080/170+0+0  XWAYLAND0

Options:

1. Both docking stations and both monitors in the office are broken. Possible, but unlikely: USB, Ethernet and power delivery was working.
2. The USB-C to USB-C cable *and* the HDMI cable are broken. Possible and less unlikely: same as above.
3. Envious sprites. Impossible and unlikely: my office is not in Ireland nor any close to Hogwarts.

P.S.
Testing again office equipment is unlikely to happen before next month as I work remotely 90% of the time.

Last edited by 0BADC0DE (2022-11-24 08:32:31)

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Maybe Computers Will Never Become As Intelligent
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ewaller

Administrator

From: Pasadena, CA

Registered: 2009-07-13

Posts: 19,769

Re: Second monitor not working anymore

Option 2 is nothing more than a symptom of option 3.  And, whether or not option 2 is driven by option 3 or by another cause, my inclination is to put my money on option 2.

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