Kubuntu 25.04 - dual monitor not working

jehoshua · June 30, 2025, 2:35am

Operating System: Kubuntu 25.04
KDE Plasma Version: 6.3.4
KDE Frameworks Version: 6.12.0
Qt Version: 6.8.3
Kernel Version: 6.14.0-22-generic (64-bit)
Graphics Platform: X11
Processors: 4 × Intel® Core™ i5-7300U CPU @ 2.60GHz
Memory: 7.6 GiB of RAM
Graphics Processor: Intel® HD Graphics 620
Manufacturer: LENOVO
System Version: ThinkPad T470s

Have setup the dual monitors in System Settings/Display config. The second monitor is a replica of the built-in screen. When I reboot, the secondary monitor seems to work okay. However, when I login it fails to display.

$ xrandr --listmonitors
Monitors: 2
 0: +*eDP-1 1920/309x1080/174+0+0  eDP-1
 1: +HDMI-2 1920/376x1080/301+0+0  HDMI-2

The secondary monitor is connected via HDMI port. Here is some more info

xrandr --query
Screen 0: minimum 320 x 200, current 1920 x 1080, maximum 16384 x 16384
eDP-1 connected primary 1920x1080+0+0 (normal left inverted right x axis y axis) 309mm x 174mm
   1920x1080     60.02*+  48.00  
   1680x1050     60.02  
   1400x1050     60.02  
   1600x900      60.02  
   1280x1024     60.02  
   1400x900      60.02  
   1280x960      60.02  
   1440x810      60.02  
   1368x768      60.02  
   1280x800      60.02  
   1280x720      60.02  
   1024x768      60.02  
   960x720       60.02  
   928x696       60.02  
   896x672       60.02  
   1024x576      60.02  
   960x600       60.02  
   960x540       60.02  
   800x600       60.02  
   840x525       60.02  
   864x486       60.02  
   700x525       60.02  
   800x450       60.02  
   640x512       60.02  
   700x450       60.02  
   640x480       60.02  
   720x405       60.02  
   684x384       60.02  
   640x360       60.02  
   512x384       60.02  
   512x288       60.02  
   480x270       60.02  
   400x300       60.02  
   432x243       60.02  
   320x240       60.02  
   360x202       60.02  
   320x180       60.02  
DP-1 disconnected (normal left inverted right x axis y axis)
HDMI-1 disconnected (normal left inverted right x axis y axis)
DP-2 disconnected (normal left inverted right x axis y axis)
HDMI-2 connected 1920x1080+0+0 (normal left inverted right x axis y axis) 376mm x 301mm
   1280x1024     60.02 +  75.02  
   1920x1080     60.00*   59.94  
   1280x960      60.00  
   1152x864      75.00  
   1280x720      60.00    59.94  
   1024x768      75.03    70.07    60.00  
   832x624       74.55  
   800x600       72.19    75.00    60.32    56.25  
   720x480       60.00    59.94  
   640x480       75.00    72.81    66.67    60.00    59.94  
   720x400       70.08

jehoshua · June 30, 2025, 10:39pm

When I boot or reboot, the secondary monitor works okay. Can see everything very clearly, entering the password, etc. However, when it completes the login it fails to display. Just an “Out of Range” message.

Where do I look in the system logs to see what is happening. I’m running Xorg, not Wayland, as I found Wayland too unstable.

jehoshua · July 1, 2025, 4:10am

Have been doing more searching, and it seems where this problem has been solved, it is usually NVIDIA driver issues. As I don’t have them installed, and after reading the post at Kde neon 6.3 nvidia driver - #2 by BulletDust , have now installed the nvidia drivers from the PPA.

Now by default, I can at least see the secondary monitor. It’s NQR, and when ever I change the settings, it is lost, no display on the secondary monitor. A reboot fixes that. I have tried to change resolution and refresh rate. This is what it looks like now ..

There is only 1 more setting to tweak and that is “Global Scale”, so will try that. These are the current settings:

BulletDust · July 1, 2025, 7:10am

Your screen is 16:9 1920x1080, but you have your resolution set to 5:4 1280x1024? Is this the problem, or is this for some reason intentional?

jehoshua · July 1, 2025, 8:21am

I tried changing the secondary display to the same resolution as the primary and it causes a loss of the secondary screen.

There will no doubt be a log file somewhere, like an nvidia one I assume.

BulletDust · July 1, 2025, 8:24am

What happens if you change resolution under nvidia-settings, paying attention to ensure your refresh rate is set to the correct refresh rate as opposed to ‘Auto’?

jehoshua · July 1, 2025, 8:50am

I must have a cutdown version of the nvidia-settings ? No where to change resolution.

I read a post where people used “Xrandr” and so tried this, it zooms out:

xrandr --output HDMI-2 --scale 2x2

no change, so tried different scaling values. Unfotunately what I did resulted in loosing the primary display and as the secondary one is truncated here and there, couldn’t view tasks, etc. Rebooted and all back again. However, that 'scaling’has changed the position of the secondary screen. beforehand, apart from being too large, it was centred. Now it is aligned left.

Will do some more reading up tomorrow on “xrandr”. Here are the current values:

xrandr
Screen 0: minimum 320 x 200, current 1920 x 1080, maximum 16384 x 16384
eDP-1 connected primary 1920x1080+0+0 (normal left inverted right x axis y axis) 309mm x 174mm
   1920x1080     60.02*+  48.00  
   1680x1050     60.02  
   1400x1050     60.02  
   1600x900      60.02  
   1280x1024     60.02  
   1400x900      60.02  
   1280x960      60.02  
   1440x810      60.02  
   1368x768      60.02  
   1280x800      60.02  
   1280x720      60.02  
   1024x768      60.02  
   960x720       60.02  
   928x696       60.02  
   896x672       60.02  
   1024x576      60.02  
   960x600       60.02  
   960x540       60.02  
   800x600       60.02  
   840x525       60.02  
   864x486       60.02  
   700x525       60.02  
   800x450       60.02  
   640x512       60.02  
   700x450       60.02  
   640x480       60.02  
   720x405       60.02  
   684x384       60.02  
   640x360       60.02  
   512x384       60.02  
   512x288       60.02  
   480x270       60.02  
   400x300       60.02  
   432x243       60.02  
   320x240       60.02  
   360x202       60.02  
   320x180       60.02  
DP-1 disconnected (normal left inverted right x axis y axis)
HDMI-1 disconnected (normal left inverted right x axis y axis)
DP-2 disconnected (normal left inverted right x axis y axis)
HDMI-2 connected 1280x1024+0+0 (normal left inverted right x axis y axis) 376mm x 301mm
   1280x1024     60.02*+  75.02  
   1920x1080     60.00    59.94  
   1280x960      60.00  
   1152x864      75.00  
   1280x720      60.00    59.94  
   1024x768      75.03    70.07    60.00  
   832x624       74.55  
   800x600       72.19    75.00    60.32    56.25  
   720x480       60.00    59.94  
   640x480       75.00    72.81    66.67    60.00    59.94  
   720x400       70.08

BulletDust · July 1, 2025, 8:53am

Hold up, that’s not right. Is this a desktop or a laptop?

More importantly, you state you used my guide to install the drivers in their current state - I assume via the Launchpad PPA? What method were you using to install drivers prior to using the Launchpad PPA?

If you were downloading binaries direct from Nvidia and installing using the supplied .run script, that’s most likely the cause of your problem - As there’s every chance you’ve overwritten important packages by installing the driver outside of your distro’s package manager.

jehoshua · July 1, 2025, 9:31pm

A Lenovo laptop T470S.

Yes, Via the PPA. Followed your instructions, however, despite the fact this has been done:

sudo apt install nvidia-driver-570

When I tried to view the info from the graphics card

nvidia-settings --glxinfo

ERROR: NVIDIA driver is not loaded

?? So, not sure why that is the case. The graphics card is about 6 years old I think

lspci | grep VGA
00:02.0 VGA compatible controller: Intel Corporation HD Graphics 620 (rev 02)

sudo lshw -C video
  *-display                 
       description: VGA compatible controller
       product: HD Graphics 620
       vendor: Intel Corporation
       physical id: 2
       bus info: pci@0000:00:02.0
       logical name: /dev/fb0
       version: 02
       width: 64 bits
       clock: 33MHz
       capabilities: pciexpress msi pm vga_controller bus_master cap_list rom fb
       configuration: depth=32 driver=i915 latency=0 resolution=1920,1080
       resources: irq:133 memory:eb000000-ebffffff memory:a0000000-afffffff ioport:e000(size=64) memory:c0000-dffff

None, as it is a fresh install of Kubuntu 25.04 on the 12th May, so in terms of attempting to get the dual monitor going, have only been using “System settings | Display”.

Definitely not. This morning , as xrandr appears to be able to adjust settings more comprehensively than system settings, I have installed

 arandr

it’s just a gui for xrandr. The first thing I noticed it it recognised the two monitors and I was able to move each one seperately, whilst in system settings/display there was only one (primary) monitor being displayed.

BulletDust · July 1, 2025, 11:32pm

Are you certain that the external monitor connection uses the same GPU? It’s not uncommon for laptops to run the external monitor hardwired off the iGPU, with the internal screen able to switch between the iGPU and the dGPU - Which results in problems similar to the ones you’re experiencing. Can you disable the iGPU in UEFI/BIOS?

nvidia-settings should still be able to see both monitors. I have a feeling your external monitor connection isn’t connected to the dGPU.

jehoshua · July 2, 2025, 4:42am

How would I tell if the external monitor uses the same GPU ? Certainly at boot time, the external monitor initially is blank but then before the login stage it starts to display. Displays a mirror of the internal display. In regards to disabling the iGPU in UEFI/BIOs, I had a good look in the BIOS, no option there.

This is what happens when I try to run nvidia-settings from the terminal

which are the same messages as https://askubuntu.com/questions/602688/nvidia-settings-not-showing-all-options

Not sure if this is relevant or not, however, in terms of installation of nvidia, from the terminal history it appears that I previously did this:

 sudo ubuntu-drivers install nvidia:535

and that was prior to the PPA installation. That said, the following commands displayed no output:

sudo ubuntu-drivers list
sudo ubuntu-drivers list-oem
sudo ubuntu-drivers devices

Some other info:

$ glxinfo | grep OpenGL
OpenGL vendor string: Intel
OpenGL renderer string: Mesa Intel(R) HD Graphics 620 (KBL GT2)
OpenGL core profile version string: 4.6 (Core Profile) Mesa 25.0.3-1ubuntu2
OpenGL core profile shading language version string: 4.60
OpenGL core profile context flags: (none)
OpenGL core profile profile mask: core profile
OpenGL core profile extensions:
OpenGL version string: 4.6 (Compatibility Profile) Mesa 25.0.3-1ubuntu2
OpenGL shading language version string: 4.60
OpenGL context flags: (none)
OpenGL profile mask: compatibility profile
OpenGL extensions:
OpenGL ES profile version string: OpenGL ES 3.2 Mesa 25.0.3-1ubuntu2
OpenGL ES profile shading language version string: OpenGL ES GLSL ES 3.20
OpenGL ES profile extensions:

lspci | grep VGA
00:02.0 VGA compatible controller: Intel Corporation HD Graphics 620 (rev 02)

I have seen a few posts where the latest nvidia driver was not suitable for older computers, therefore all that was required was to install an earlier release.