[kde] [Bug 485842] New: External displays not detected by KDE Plasma 6.0.4

[Dylan Meysmans]

https://bugs.kde.org/show_bug.cgi?id=485842

            Bug ID: 485842
           Summary: External displays not detected by KDE Plasma 6.0.4
    Classification: I don't know
           Product: kde
           Version: unspecified
          Platform: openSUSE
                OS: Linux
            Status: REPORTED
          Severity: normal
          Priority: NOR
         Component: general
          Assignee: unassigned-bugs at kde.org
          Reporter: contact at mettekou.com
  Target Milestone: ---

***
If you're not sure this is actually a bug, instead post about it at
https://discuss.kde.org

If you're reporting a crash, attach a backtrace with debug symbols; see
https://community.kde.org/Guidelines_and_HOWTOs/Debugging/How_to_create_useful_crash_reports
***

SUMMARY

Under Wayland and X11, KDE Plasma 6.0.4 does not detect external displays
connected to my laptop via USB-C DisplayPort, either when connected before
starting the laptop up or during the Plasma session.

STEPS TO REPRODUCE
1. Connect an external display via USB-C DisplayPort, either before starting up
the laptop or during the Plasma session.

OBSERVED RESULT
Nothing happens.

EXPECTED RESULT
The external display is detected and becomes visible in display settings.

SOFTWARE/OS VERSIONS
Windows: 
macOS: 
Linux/KDE Plasma: openSUSE Tumbleweed 20240418
(available in About System)
KDE Plasma Version: 6.0.4
KDE Frameworks Version: 6.1.0
Qt Version: 6.7.0

ADDITIONAL INFORMATION
The machine has an AMD Radeon 610M internal GPU and an Nvidia GeForce RTX 4090
Laptop discrete GPU and a MUX switch. Whether the MUX switch is on or off makes
no difference. The proprietary Nvidia drivers, version 550.67 are installed.
Offloading using the environment variables works fine on the internal display
and there are no issues with running games or other applications offloaded on
the Nvidia GPU using the environment variables "__NV_PRIME_RENDER_OFFLOAD=1
__GLX_VENDOR_LIBRARY_NAME=nvidia __GL_SYNC_TO_VBLANK=". There are no issues
with running applications on the internal GPU. KDE Plasma 6.0.3 did detect the
external displays under Wayland (I did not check X11 on 6.0.3) and correctly
allowed me to select the maximum resolution for them, but this caused them to
turn black, leading me to use them at a lower resolution, which worked fine,
with the MUX switch set to either discrete GPU only or hybrid graphics.
However, since I could not use them at their maximum resolution, so that was
not ideal either.

-- 
You are receiving this mail because:
You are the assignee for the bug.