Created attachment 148935 [details] kscreen-console bug when EDID is not read correctly SUMMARY When plugging in my monitor, KScreen sometimes reads EDID data before the display is fully connected. This leads to it sometimes reading the display as "unknown HDMI-A-1 unknown" or "BOE". The differing EDID data often results in loading the wrong config. This GNOME thing may be of use: https://bugzilla.gnome.org/show_bug.cgi?id=779837 STEPS TO REPRODUCE 1. Open System Settings > Hardware > Display Configuration 2. Repeatedly plug and unplug the external monitor. OBSERVED RESULT The external monitor is sometimes seen as "unknown HDMI-A-1 unknown" or "BOE". EXPECTED RESULT When the external monitor is plugged in, it should always display as "Samsung Electric Company LF24T35". SOFTWARE/OS VERSIONS Linux/KDE Plasma: ArcoLinux (available in About System) KDE Plasma Version: 5.24.5 KDE Frameworks Version: 2.94.0 Qt Version: 5.15.4 ADDITIONAL INFORMATION See the attachment for a kscreen-console dump when things go wrong.
Very interesting observations, thanks.
I have noticed the same bug, but I am not sure it is caused by reading the EDID before it is fully connected, exactly. It may be that KScreen tries to read it before the EDID info is _fully transferred_. My reasoning for this is that I see the same problem when plugging in a display that's connected via USB-C dock (where the port would have to be fully connected in order to do the handshaking necessary to switch to DP alt mode). Possibly related reddit post: https://www.reddit.com/r/kde/comments/staakr/unknown_displays/
If anything, a small workaround *might* be possible, but I can't seem to find a way to force KScreen to reload its configuration.
Update with 5.25.1: the bug seems to persist somewhat. If I launch Plasma without plugging in my monitor, the first time I plug it in, it will show as "unknown HDMI-A-1 unknown". However, when I plug it in the second time, it is recognized correctly. Still quite annoying.
does this happen on wayland? x11? or both?
Only happens on Wayland in my testing.
Kernel 6.2.1 and Plasma 5.27.2, can no longer reproduce this issue. I guess it must be fixed!
Good news! Makes sense given all the multi-monitor fixes that made it into that release. Jacky Guo, what about you? Are you able to reproduce the bug in Plasma 5.27.2 or later?
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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!