Created attachment 156529 [details] screenshot of one of the screens with shorter identify string (with already applied workaround) SUMMARY When having two monitors from the same vendor where in the serial number only the last digit differs, the multiscreen setup is not stored correctly. In the office we have quite a lot of the same monitors from the same vendor and on one of the shared places two monitors with nearly the same id are placed next to each other. A screen setup with those does not work. While the Configuration screen inside the Settings shows the 13digit serialnumber (the number between the name and the resolution) correctly, the identify function only shows the first 12 digits, so my guess is that the settings only store 12 as well, which then mixes them randomly at each start. STEPS TO REPRODUCE 1. get two screens, with nearly the same id (has to change after the 12th digit) 2. connect to pc 3. configure 4. reboot 5. rearranged, if not go back to 4 again OBSERVED RESULT Mixed up screen setup after reboot EXPECTED RESULT use the correct id of 13 digits (or more if there are more given) WORKAROUND Exchange monitors from shared desk until they differ in at least the 12th digit. This does not work if you only got two monitors. ADDITIONAL INFORMATION The screens are: "Iiyama North America PL2893UH"
Fascinating
A possibly relevant merge request was started @ https://invent.kde.org/plasma/kwin/-/merge_requests/3684
Git commit 693ea96599c76df03b522fa4f180edf2f4041526 by David Redondo. Committed on 24/02/2023 at 11:06. Pushed by davidre into branch 'master'. Fix edid serial parsing Descriptor blocks are 18 bytes, the serial number one has space for 13 bytes of serial number. FIXED-IN:5.27.2 M +3 -3 src/utils/edid.cpp https://invent.kde.org/plasma/kwin/commit/693ea96599c76df03b522fa4f180edf2f4041526
Git commit fb59d975b5377f858b94dbfe333256ec9c4bfd6d by David Redondo. Committed on 24/02/2023 at 11:06. Pushed by davidre into branch 'Plasma/5.27'. Fix edid serial parsing Descriptor blocks are 18 bytes, the serial number one has space for 13 bytes of serial number. FIXED-IN:5.27.2 (cherry picked from commit 693ea96599c76df03b522fa4f180edf2f4041526) M +3 -3 src/utils/edid.cpp https://invent.kde.org/plasma/kwin/commit/fb59d975b5377f858b94dbfe333256ec9c4bfd6d