Created attachment 153265 [details] kscreen_backend_launcher logs SUMMARY I have an XPS laptop with 2 externals monitor. Since today, and after having updated some KDE packages, I cannot use 2 external monitors in plasma. I can use one or the other, but not both at the same time. I do not have this issue in tty, sddm3 or gnome. STEPS TO REPRODUCE 1. Open "Display Configuration" 2. Select 1st external display and enable it 3. Click apply => works fine 4. On the dialog prompting if settings should be kept or reverted, select to keep the settings. 5. Select 2nd external display and enable it 6. Click apply... nothings happen OBSERVED RESULT When clicking "Apply" in step 6, the button Apply is greyed out. But nothing else seems to happen, the dialog to ask use if changes should be kept or reverted is not displayed. The 2nd display is effectively still disabled. EXPECTED RESULT The 2nd screen is effectively enabled and taken out of stand by. SOFTWARE/OS VERSIONS Kubuntu 22.04 + backport PPA Linux: 5.15.0-48-generic KDE Plasma Version: 5.24.7 KDE Frameworks Version: 5.98.0 Qt Version: 5.15.3 ADDITIONAL INFORMATION
After more investigation it seems linked to recent nvidia drivers. nvidia-driver-470: OK nvidia-driver-510: OK nvidia-driver-515: OK nvidia-driver-520: Bug nvidia-driver-515-open: Bug nvidia-driver-520-open: Bug When using faulty drivers I have this in dmesg: GPU 0000:01:00.0: RmInitAdapter failed! (0x63:0x0:1900) NVRM: GPU 0000:01:00.0: rm_init_adapter failed, device minor number 0 [drm:nv_drm_load [nvidia_drm]] *ERROR* [nvidia-drm] [GPU ID 0x00000100] Failed to allocate NvKmsKapiDevice [drm:nv_drm_probe_devices [nvidia_drm]] *ERROR* [nvidia-drm] [GPU ID 0x00000100] Failed to register device But again, only KDE/Plasma is affected: gnome (x11) and sddm3 can mae use of the 2 external monitors at the same time.
Ok, so I went a bit too fast with my last comment. After I was done testing I tried to revert to one the working driver versions, but actually none of them worked anymore. I could not make the 2 external monitors with any driver versions, regardless of the presence of the dmesg error. I even tried to use nouveau without any success. I tried upgrading to Plasma 5.25.5 using the backport-extra ppa, but it did not change anything.
Can you please Paste the output of `kscreen-doctor -o` before you click the Apply button, and then again afterwards? Thanks!
Created attachment 153762 [details] Result of `kscreen-doctor -o` Added the result of kscreen-doctor -o With the USB hub connected on 2 different USB-C ports. For both ports the output before and after clicking Apply are the same
Hmm, everything that was "enabled connected" in the Before output is still "enabled connected" in the After output. The outputs are identical. Which means KScreen appears to be doing the right thing here, and the issue is KWin failing to send video to the monitor. Moving to KWin. Still probably an NVIDIA driver bug, but maybe we can work around it somehow...?
Is this still happening with KWin 5.27.7?
Dear Bug Submitter, This bug has been in NEEDSINFO status with no change for at least 15 days. Please provide the requested information as soon as possible and set the bug status as REPORTED. Due to regular bug tracker maintenance, if the bug is still in NEEDSINFO status with no change in 30 days the bug will be closed as RESOLVED > WORKSFORME due to lack of needed information. For more information about our bug triaging procedures please read the wiki located here: https://community.kde.org/Guidelines_and_HOWTOs/Bug_triaging If you have already provided the requested information, please mark the bug as REPORTED so that the KDE team knows that the bug is ready to be confirmed. Thank you for helping us make KDE software even better for everyone!
This bug has been in NEEDSINFO status with no change for at least 30 days. The bug is now closed as RESOLVED > WORKSFORME due to lack of needed information. For more information about our bug triaging procedures please read the wiki located here: https://community.kde.org/Guidelines_and_HOWTOs/Bug_triaging Thank you for helping us make KDE software even better for everyone!