https://bugs.kde.org/show_bug.cgi?id=453557
Bug ID: 453557 Summary: Black screen when waking up the computer in 4K resolution with KDE and an HDMI Edid emulator connected Product: kde Version: unspecified Platform: Other OS: Linux Status: REPORTED Severity: normal Priority: NOR Component: general Assignee: unassigned-b...@kde.org Reporter: rondo...@gmail.com Target Milestone: --- SUMMARY When the computer cable is connected to an HDMI Edid emulator and the screen resolution is in 4K, when the computer sleeps from KDE and then wakes up, the monitor does not receive HDMI video signal and only black screen is displayed. When you switch sessions by pressing the Ctrl+Alt+F1 keys, the computer starts sending the HDMI signal to the monitor and then you can see the screen perfectly. This problem does not occur on the Windows operating system nor does it occur with the GNOME desktop environment (tested with Fedora and Manjaro). In GNOME this works perfectly when the screen is in 4K resolution. It also does not happen if the KDE resolution at the time of suspending the computer is set to less than 4K resolution, but if it is 4K or higher, the problem I just mentioned occurs. It does not depend on the Linux kernel either, I have tried with versions 5.16, 5.17 and 5.18 and the same thing happens in all of them from KDE. STEPS TO REPRODUCE 1. Have an HDMI Edid emulator connected to the computer (or a KVM switch) in the HDMI input, and have the HDMI cable from the computer connected to the HDMI Edid emulator --> (HDMI Edid emulator: https://www.evanlak.com/products /hdmi-edid-emulator-4k-120hz). 2. Have the screen resolution in 4K mode (3840x2160). 3. Put the computer in sleep mode and wait a few seconds. 4. Wake up the computer. OBSERVED RESULT When I wake up the computer, the screen is completely black, the monitor does not receive an HDMI video signal. It doesn't react until you press (for example) Ctrl+Alt+F1 to switch sessions. By doing so, the monitor begins to receive the video signal and is already displayed correctly. In KDE it works correctly with the HDMI Edid emulator connected if the screen resolution is less than 4K, but from 4K resolution the problem that I mentioned occurs that the screen stays black when waking up the computer. I have tried several distros with GNOME (Fedora and Manjaro) and with this desktop environment it works perfectly having the HDMI Edid emulator connected, the computer can be suspended in 4K resolution and when it wakes up it shows the screen correctly again. However, I have tried several distros with KDE (Manjaro and KDE Neon) and in both the same thing happens, when suspending the computer in 4K resolution with the HDMI Edid emulator connected, when waking it up the screen is black until it is changed from session. I have also tried several Linux kernels (5.16, 5.17 and 5.18) and the same thing happens in all of them. It doesn't seem like a problem with the kernel, but with KDE, since as I say in the GNOME distros it works perfectly. In the Windows operating system it also works perfectly, if I suspend the computer with the screen at 4K resolution, when I wake it up it is displayed correctly. EXPECTED RESULT As it happens in the GNOME desktop environment, when you wake up the computer it should correctly display the KDE screen and not get a black screen on the monitor without receiving an HDMI signal. SOFTWARE/OS VERSIONS Windows: macOS: Linux/KDE Plasma: 5.24.5 (available in About System) KDE Plasma Version: 5.24.5 KDE Frameworks Version: 5.93.0 Qt Version: 5.15.3 ADDITIONAL INFORMATION My computer is an AMD Ryzen 5 3550H with Radeon Vega Mobile GFX, the GPU is an integrated AMD Radeon Vega 8 Graphics. Linux is using the video-linux driver (Picasso [ATI Technologies Inc]). -- You are receiving this mail because: You are watching all bug changes.