502630 2025-04-10 03:27:41 +0000 Screen Mirroring doesn't take monitor rotation into account 2025-04-16 15:55:02 +0000 1 1 4 Plasma kwin multi-screen 6.3.4 Fedora RPMs Linux RESOLVED FIXED multiscreen NOR normal --- 0 will kwin-bugs-null john kdedev nate xaver.hugl https://invent.kde.org/plasma/kwin/-/commit/3e0ecbaad2981874608118005d4dc28daf6e3ec4 0 oldest_to_newest 2414528 0 will 2025-04-10 03:27:41 +0000 SUMMARY This is a bit of an odd one. I have a device (GPD Pocket 4) which has a display which is wired to be vertical, used horizontally. As a result, I need to use screen rotation to get the proper aspect ratio horizontally. Kwin does fine with this, using display settings. However, when I connect a second monitor, everything goes off the rails. STEPS TO REPRODUCE 1. Have a display which is properly oriented only when rotated. 2. Connect a second monitor which is naturally oriented. 3. Hit "Mirror Screens" EXPECTED The built in display mirrors the external display, letterboxing where needed, with both displays oriented as they would be if selected individually, at a shared resolution. OBSERVED RESULT Depending on rotation in display settings, the 16:10 internal display is mirrored as a 10:16 display which is oriented correctly (but aggressively letterboxed, and in an aspect ratio not reproducible on the second display) OR, the screens are mirrored properly, but the built-in display is oriented according to the natural (right side down) rotation of the screen, and letterboxing takes up the majority of the screen. Put differently, there appears to be no permutation of display settings which results in both the correct orientation of the screen, and the correct, horizontal is wider aspect ratio. You can choose one, or the other, and the Meta+P mirror displays command gives the 10:16 version, which is arguably the worse of the two. Changing display orientation at the kernel level does not appear to fix this, although it does make the LUKS unlock orient properly. Thanks! SOFTWARE/OS VERSIONS Operating System: Fedora Linux 41 KDE Plasma Version: 6.3.4 KDE Frameworks Version: 6.12.0 Qt Version: 6.8.2 Kernel Version: 6.13.9-200.fc41.x86_64 (64-bit) Graphics Platform: Wayland Processors: 24 × AMD Ryzen AI 9 HX 370 w/Radeon 890M Memory: 30.9 GiB of RAM Graphics Processor: AMD Radeon Graphics 2414806 1 will 2025-04-10 20:26:14 +0000 OK, I've found a way to coerce display settings into giving the desired output, confirming that this is software, not hardware. On the built in screen, in Display Settings, I need: - Enabled, Primary, 1600x2560 (10:16) - 90 CCW rotation Manual On the external screen, I need: - Enabled, Not Primary, 1680x1050 (16:10) - No Rotation, Manual - Replica of Built-In Screen Note the counterintuitive fact that the aspect ratio is listed as different for the two screens, even though they are displaying the same content. This creates the desired mirroring effect. However, when I pull up the Display Switcher with Meta+P and hit mirror displays, it creates: 2414807 2 will 2025-04-10 20:34:32 +0000 Apologies for the spam. Turns out Tab doesn't do tab things here. When I hit Mirror Displays from Meta+P, I get Primary Display: - Enabled, Primary, 1600x2560 (10:16) - 90 CCW rotation Manual But oddly, the 10:16 is actually displayed as a vertical rectangle with heavy letterboxing, which constrains the usable space on the other monitor. External: - Enabled, Not Primary, 1920x1080 (16:9) - No Rotation, Manual - Replica of Built-In Screen For reference, the native resolution of the external display is 1920x1080, and of the internal display (when rotated properly) is 1600x2560 (which is listed in Display setup as being 1600x2560, despite that not being what is displayed). Sorry for the deep dive here, but I think I found a corner case and wanted to flag it to the project. Thanks! 2415549 3 john 2025-04-13 06:10:17 +0000 I can't reproduce this one myself, but for reference for others...I wonder if this is possibly related to https://bugs.kde.org/show_bug.cgi?id=502374 ? 2416357 4 xaver.hugl 2025-04-16 15:55:02 +0000 Git commit 3e0ecbaad2981874608118005d4dc28daf6e3ec4 by Xaver Hugl. Committed on 16/04/2025 at 15:20. Pushed by zamundaaa into branch 'master'. outputconfigurationstore: implement better screen mirroring Instead of KScreen trying to move and scale outputs in a way that kind of looks like mirroring, this makes KWin aware of which outputs replicate which, and makes it responsible for implementing mirroring in whatever way is best. This commit implements simliar workarounds like KScreen had, with the only real difference being that it avoids modifying the source display mode and position, and takes screen rotation into account. A better implementation can replace that bit later on, while making use of the same information stored in the configuration. Related: bug 481222 M +11 -6 autotests/integration/outputchanges_test.cpp M +1 -0 src/backends/drm/drm_output.cpp M +1 -0 src/backends/virtual/virtual_output.cpp M +1 -0 src/backends/wayland/wayland_output.cpp M +9 -0 src/core/output.cpp M +3 -0 src/core/output.h M +1 -0 src/core/outputconfiguration.h M +88 -0 src/outputconfigurationstore.cpp M +2 -0 src/outputconfigurationstore.h M +26 -1 src/wayland/outputdevice_v2.cpp M +1 -0 src/wayland/outputdevice_v2.h M +12 -1 src/wayland/outputmanagement_v2.cpp M +4 -3 src/workspace.cpp M +1 -1 src/workspace.h https://invent.kde.org/plasma/kwin/-/commit/3e0ecbaad2981874608118005d4dc28daf6e3ec4