488111 2024-06-06 13:50:59 +0000 "Unifying output" with an external screen may lead to internal screen not working at all. 2025-07-22 20:05:39 +0000 1 1 4 Plasma kwin wayland-generic 6.0.5 Other Linux RESOLVED DUPLICATE 481222 multiscreen NOR normal --- 1 tobiaspotocek kwin-bugs-null kde nate tamalero xaver.hugl https://invent.kde.org/plasma/kwin/-/commit/daf4d58276575e139a5a2841c004f66cd308e727 6.1.0 0 oldest_to_newest 2325026 0 170204 tobiaspotocek 2024-06-06 13:50:59 +0000 Created attachment 170204 Broken kwinoutputconfig.json *** 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 Selecting "unify outputs" when connecting an external screen to my laptop permanently disables the laptop screen, pretty much bricking the system. STEPS TO REPRODUCE 1. Connect an external screen to a laptop 2. Select "unify outputs" OBSERVED RESULT 1. The internal laptop screen goes black. 2. After disconnecting the screen, the screen stays black. 3. After hard-reset, the login screen shows up, but after sign in, it goes black again. 4. Under a different user, the screen works normally. EXPECTED RESULT "Unify output" actually unifies output. Both screens work, and after disconnection the internal laptop screen keeps working as usual. HOW TO RECOVER 1. Find an external screen that works. 2. Create another user. 3. Sign into that user (the internal screen should work normally). 4. Remove .config/kwinoutputconfig.json from your main user home directory. Note that it is necessary to go through that another user because if you delete the file directly, KDE will simply recreate it with the same content. SOFTWARE/OS VERSIONS Linux/KDE Plasma: Fedora Linux 40 KDE Plasma Version: 6.0.5 KDE Frameworks Version: 6.2.0 Qt Version: 6.7.1 Using Wayland on Lenovo Thinkpad T14s with AMD Ryzen 7 PRO 7840U. ADDITIONAL INFORMATION This is very annoying problem because it pretty much bricks the system. Not sure how I reproducible this is but in my current setup (the aforementioned laptop + a ThinkVision external screen connected via USB-C) I managed to reproduce it immediately on a new account. I'm attaching kwinoutputconfig.json causing the issue. 2325044 1 xaver.hugl 2024-06-06 14:44:41 +0000 *** This bug has been marked as a duplicate of bug 481222 *** 2326956 2 xaver.hugl 2024-06-12 11:59:19 +0000 Git commit 35a7e30952c764a943a84a032715be8baee9d9ca by Xaver Hugl. Committed on 12/06/2024 at 11:50. Pushed by zamundaaa into branch 'master'. backends/drm: set scaling mode to full aspect with generated modes on internal displays While the scaling mode has caused some issues with external displays, we've had several reports that using "unify outputs" has caused the internal display to no longer show anything, as it changes to an unsupported mode. This sets the scaling mode so that the driver handles the scaling internally, instead of leaving it up to the panel, and it only does so on internal displays with generated modes, to minimize the risk of further breakage. M +6 -2 src/backends/drm/drm_pipeline.cpp https://invent.kde.org/plasma/kwin/-/commit/35a7e30952c764a943a84a032715be8baee9d9ca 2326964 3 xaver.hugl 2024-06-12 12:30:12 +0000 Git commit daf4d58276575e139a5a2841c004f66cd308e727 by Xaver Hugl. Committed on 12/06/2024 at 12:12. Pushed by zamundaaa into branch 'Plasma/6.1'. backends/drm: set scaling mode to full aspect with generated modes on internal displays While the scaling mode has caused some issues with external displays, we've had several reports that using "unify outputs" has caused the internal display to no longer show anything, as it changes to an unsupported mode. This sets the scaling mode so that the driver handles the scaling internally, instead of leaving it up to the panel, and it only does so on internal displays with generated modes, to minimize the risk of further breakage. (cherry picked from commit 35a7e30952c764a943a84a032715be8baee9d9ca) Co-authored-by: Xaver Hugl <xaver.hugl@gmail.com> M +6 -2 src/backends/drm/drm_pipeline.cpp https://invent.kde.org/plasma/kwin/-/commit/daf4d58276575e139a5a2841c004f66cd308e727 2326970 4 tobiaspotocek 2024-06-12 12:43:58 +0000 Thanks a lot for the quick response ❤️ 2398546 5 tamalero 2025-02-16 14:39:10 +0000 Nobara 41 ( Fedora Core ) Had the same issue. But I never did unify outputs at all. And I'm on a desktop with 3 monitors. 2 of them identical. Screen configuration output: https://pastebin.com/wC0KChQx As others mentioned, Bios, Login, everything works for this screen. As soon as you login, boom. The screen goes black but remains active ( Does not go to sleep), Which shows that it is just outputting an empty desktop with nothing active and absolutely no content. *** What happened: Was on Nobara 41 Kernel 6.12.X Installed the latest Nobara sync ( 6.13.X ) After the second reboot. Problem started. Resolution: Deleted the file kwinoutputconfig.json and performed the kill all command on kwin and things were back to to default. Reconfiguring my settings and everything now works as expected. Specs: Operating System: Nobara Linux 41 KDE Plasma Version: 6.3.0 KDE Frameworks Version: 6.10.0 Qt Version: 6.8.2 Kernel Version: 6.13.2-200.nobara.fc41.x86_64 (64-bit) Graphics Platform: Wayland Processors: 32 × Intel® Core™ i9-14900K Memory: 62.6 GiB of RAM Graphics Processor 1: NVIDIA GeForce RTX 4090/PCIe/SSE2 Graphics Processor 2: NVIDIA GeForce RTX 4090/PCIe/SSE2 Manufacturer: Gigabyte Technology Co., Ltd. Product Name: Z690 AORUS PRO System Version: -CF 2442303 6 xaver.hugl 2025-07-22 20:05:39 +0000 *** This bug has been marked as a duplicate of bug 481222 *** 170204 2024-06-06 13:50:59 +0000 2024-06-06 13:50:59 +0000 Broken kwinoutputconfig.json kwinoutputconfig.json application/json 2830 tobiaspotocek WwogICAgewogICAgICAgICJkYXRhIjogWwogICAgICAgICAgICB7CiAgICAgICAgICAgICAgICAi YXV0b1JvdGF0aW9uIjogIkluVGFibGV0TW9kZSIsCiAgICAgICAgICAgICAgICAiY29ubmVjdG9y TmFtZSI6ICJlRFAtMSIsCiAgICAgICAgICAgICAgICAiZWRpZEhhc2giOiAiNWU1YjUzMjYyNGQx YzMzZmFiNTYzMGY3ZmMwZTRkYzEiLAogICAgICAgICAgICAgICAgImVkaWRJZGVudGlmaWVyIjog IlNEQyAxNjc4NyAwIDM1IDIwMjAgMCIsCiAgICAgICAgICAgICAgICAiaGlnaER5bmFtaWNSYW5n ZSI6IGZhbHNlLAogICAgICAgICAgICAgICAgImljY1Byb2ZpbGVQYXRoIjogIiIsCiAgICAgICAg ICAgICAgICAibW9kZSI6IHsKICAgICAgICAgICAgICAgICAgICAiaGVpZ2h0IjogMTYyMCwKICAg ICAgICAgICAgICAgICAgICAicmVmcmVzaFJhdGUiOiA1OTk2MCwKICAgICAgICAgICAgICAgICAg ICAid2lkdGgiOiAyODgwCiAgICAgICAgICAgICAgICB9LAogICAgICAgICAgICAgICAgIm92ZXJz Y2FuIjogMCwKICAgICAgICAgICAgICAgICJyZ2JSYW5nZSI6ICJBdXRvbWF0aWMiLAogICAgICAg ICAgICAgICAgInNjYWxlIjogMiwKICAgICAgICAgICAgICAgICJzZHJCcmlnaHRuZXNzIjogMjAw LAogICAgICAgICAgICAgICAgInNkckdhbXV0V2lkZW5lc3MiOiAwLAogICAgICAgICAgICAgICAg InRyYW5zZm9ybSI6ICJOb3JtYWwiLAogICAgICAgICAgICAgICAgInZyclBvbGljeSI6ICJBdXRv bWF0aWMiLAogICAgICAgICAgICAgICAgIndpZGVDb2xvckdhbXV0IjogZmFsc2UKICAgICAgICAg ICAgfSwKICAgICAgICAgICAgewogICAgICAgICAgICAgICAgImF1dG9Sb3RhdGlvbiI6ICJJblRh YmxldE1vZGUiLAogICAgICAgICAgICAgICAgImNvbm5lY3Rvck5hbWUiOiAiRFAtMiIsCiAgICAg ICAgICAgICAgICAiZWRpZEhhc2giOiAiNTQ0MDI3ODQzZTdmZTJlYmJiYmNmZDY2ODYwNmY4ZDUi LAogICAgICAgICAgICAgICAgImVkaWRJZGVudGlmaWVyIjogIkxFTiAyNTA1MCA4NDI1NTM2OTAg MjUgMjAyMCAwIiwKICAgICAgICAgICAgICAgICJoaWdoRHluYW1pY1JhbmdlIjogZmFsc2UsCiAg ICAgICAgICAgICAgICAiaWNjUHJvZmlsZVBhdGgiOiAiIiwKICAgICAgICAgICAgICAgICJtb2Rl IjogewogICAgICAgICAgICAgICAgICAgICJoZWlnaHQiOiAxNjIwLAogICAgICAgICAgICAgICAg ICAgICJyZWZyZXNoUmF0ZSI6IDU5OTYwLAogICAgICAgICAgICAgICAgICAgICJ3aWR0aCI6IDI4 ODAKICAgICAgICAgICAgICAgIH0sCiAgICAgICAgICAgICAgICAib3ZlcnNjYW4iOiAwLAogICAg ICAgICAgICAgICAgInJnYlJhbmdlIjogIkF1dG9tYXRpYyIsCiAgICAgICAgICAgICAgICAic2Nh bGUiOiAyLAogICAgICAgICAgICAgICAgInNkckJyaWdodG5lc3MiOiAyMDAsCiAgICAgICAgICAg ICAgICAic2RyR2FtdXRXaWRlbmVzcyI6IDAsCiAgICAgICAgICAgICAgICAidHJhbnNmb3JtIjog Ik5vcm1hbCIsCiAgICAgICAgICAgICAgICAidnJyUG9saWN5IjogIkF1dG9tYXRpYyIsCiAgICAg ICAgICAgICAgICAid2lkZUNvbG9yR2FtdXQiOiBmYWxzZQogICAgICAgICAgICB9CiAgICAgICAg XSwKICAgICAgICAibmFtZSI6ICJvdXRwdXRzIgogICAgfSwKICAgIHsKICAgICAgICAiZGF0YSI6 IFsKICAgICAgICAgICAgewogICAgICAgICAgICAgICAgImxpZENsb3NlZCI6IGZhbHNlLAogICAg ICAgICAgICAgICAgIm91dHB1dHMiOiBbCiAgICAgICAgICAgICAgICAgICAgewogICAgICAgICAg ICAgICAgICAgICAgICAiZW5hYmxlZCI6IHRydWUsCiAgICAgICAgICAgICAgICAgICAgICAgICJv dXRwdXRJbmRleCI6IDAsCiAgICAgICAgICAgICAgICAgICAgICAgICJwb3NpdGlvbiI6IHsKICAg ICAgICAgICAgICAgICAgICAgICAgICAgICJ4IjogMCwKICAgICAgICAgICAgICAgICAgICAgICAg ICAgICJ5IjogMAogICAgICAgICAgICAgICAgICAgICAgICB9LAogICAgICAgICAgICAgICAgICAg ICAgICAicHJpb3JpdHkiOiAwCiAgICAgICAgICAgICAgICAgICAgfQogICAgICAgICAgICAgICAg XQogICAgICAgICAgICB9LAogICAgICAgICAgICB7CiAgICAgICAgICAgICAgICAibGlkQ2xvc2Vk IjogZmFsc2UsCiAgICAgICAgICAgICAgICAib3V0cHV0cyI6IFsKICAgICAgICAgICAgICAgICAg ICB7CiAgICAgICAgICAgICAgICAgICAgICAgICJlbmFibGVkIjogdHJ1ZSwKICAgICAgICAgICAg ICAgICAgICAgICAgIm91dHB1dEluZGV4IjogMCwKICAgICAgICAgICAgICAgICAgICAgICAgInBv c2l0aW9uIjogewogICAgICAgICAgICAgICAgICAgICAgICAgICAgIngiOiAwLAogICAgICAgICAg ICAgICAgICAgICAgICAgICAgInkiOiAwCiAgICAgICAgICAgICAgICAgICAgICAgIH0sCiAgICAg ICAgICAgICAgICAgICAgICAgICJwcmlvcml0eSI6IDEKICAgICAgICAgICAgICAgICAgICB9LAog ICAgICAgICAgICAgICAgICAgIHsKICAgICAgICAgICAgICAgICAgICAgICAgImVuYWJsZWQiOiB0 cnVlLAogICAgICAgICAgICAgICAgICAgICAgICAib3V0cHV0SW5kZXgiOiAxLAogICAgICAgICAg ICAgICAgICAgICAgICAicG9zaXRpb24iOiB7CiAgICAgICAgICAgICAgICAgICAgICAgICAgICAi eCI6IDE0NDAsCiAgICAgICAgICAgICAgICAgICAgICAgICAgICAieSI6IDAKICAgICAgICAgICAg ICAgICAgICAgICAgfSwKICAgICAgICAgICAgICAgICAgICAgICAgInByaW9yaXR5IjogMAogICAg ICAgICAgICAgICAgICAgIH0KICAgICAgICAgICAgICAgIF0KICAgICAgICAgICAgfQogICAgICAg IF0sCiAgICAgICAgIm5hbWUiOiAic2V0dXBzIgogICAgfQpdCg==