Created attachment 162503 [details]
Framework 13 dmesg

SUMMARY
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When using Wayland, both SDDM and the plasma desktop will immediately cause my external monitor to lose all signal when connected through a USB-C dock. Once it has lost signal this way, it will not recover without rebooting the laptop. While signal is gone, the monitor still shows up in display manager as though it were still connected, and the laptop screen still registers as the secondary display. I have seen this behavior now with 2 laptops, one with an Nvidia GPU and one without a dGPU (Asus x13 - 6900HS + 3050ti, Framework 13 - 7840U). The Asus laptop runs Fedora 38 KDE spin, the Framework is running Fedora 39 Beta with KDE installed alongside gnome. The dock is a lenovo universal USB-C dock. If I use Gnome instead of plasma, display output shows as expected even with Wayland.

KDE/SDDM + X11 + dock = works
Gnome + wayland + dock = works
KDE/SDDM + wayland + direct cable to monitor = works
KDE/SDDM + wayland + dock = display output immediately lost
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STEPS TO REPRODUCE
1. USB-C dock connects to monitor via HDMI
2. USB-C port with DP alt mode connects from laptop to dock (I have only tested with recent model AMD APUs using RDNA3 based iGPUs - unsure if this is required condition)
3. Attempt to render either SDDM or plasma desktop using Wayland

OBSERVED RESULT
External monitor loses signal completely, but still shows up in display settings. Display signal will not restore until laptop is rebooted.

EXPECTED RESULT
External monitor displays SDDM or plasma desktop.


SOFTWARE/OS VERSIONS
Windows: 
macOS: 
Linux/KDE Plasma: Seen on both Fedora 38 KDE spin (kernel 6.5.7-200) and Fedora 39 Beta (Kernel 6.5.7-300, although this behavior is not new and has been present with older kernels)
(available in About System)
KDE Plasma Version: 5.27.8
KDE Frameworks Version: 5.110.0
Qt Version: 5.15.10

ADDITIONAL INFORMATION

After monitor loses signal, I get trace output in dmesg on both laptops which I am attaching.