Hi there :) Last year, I ran into an issue where the selection of a resolution for my TV in KScreen resulted in the device being entirely unusable for this installation. There was no way discovered, despite multiple issues and conversations with people on different Matrix channels, to restore its functionality as an external display. Here is the issue, if details are interesting: https://bugs.kde.org/show_bug.cgi?id=484592 Now, I managed to get myself into a similar situation, just that this time it's not the OSD menu that caused the situation, but some magic. I had the mouse cursor in the bottom right of the screen when I plugged in the display, and as soon as I realized that I chose the problematic resolution that is not supported by my TV, my hand slipped, and I accidentally did a left click. I don't know how it managed to reach the confirmation box, which was seated right in the middle of the screen, but apparently it did. So, my real issue is that there is no way to restore the default configuration for said display (that would just select the highest resolution, which one is supported) by *ANY* means possible. So far as I know, does KWin violate the fundamental UNIX principle that everything is editable in the form of a text file. Even worse, is that the file in question, kwinoutputconfig.json, does not even say that. It just rests there, innocently, and pretends to be editable like every other file. Changing it does not do anything, and without asking the actual maintainers, there is no way anyone would ever know; this file is not even meant to be edited by hand. It's auto-generated somehow, and I don't know how I could possibly cause an edit, since the TV is not even recognized anymore by KScreen, when it's connected. I tried with remote desktop solutions, to edit the setting this way, but not even that is possible. Currently, there is no way to go back to a working state, without having to reinstall the entire operating system.
I ran into a very similar problem with a similar setup - an HTPC (running CachyOS with Plasma) connected to a TV over HDMI as the only display. The details leading up to the result are a little different but the result was the same - a blank display and no easy way of recovering. Note: There are ways of recovering which don't require reinstalling the system, but that's tangential. The user should have an easy way to recover from the situation. Details: - The TV was turned off, and the system was left on (no sleep / hibernate) - Due to some problem we haven't gotten to the root of, after turning on the TV, sometimes the backlight would come on but not display the desktop. Sometimes, the desktop would be in a corner of the TV display. - To get the display back to normal, if the UI is visible, we go to Display Configuration - choose a lower resolution, apply, choose the correct resolution, apply. **However** one time, I chose a resolution the TV couldn't display. It went blank and then showed a message (from by the TV) that the resolution was not supported, and to choose a different resolution. Note: I had not clicked Keep. I expected that when the timeout was reached, and the change was reverted, that the TV would display the desktop again, but this didn't happen. This got the TV into the same state as described in the first comment. In situations like this, it would be nice to have some sane fallback that allows the user to regain access to the UI and recover In the Windows world, when a graphics driver crashes, the UI is able to fall back to a very low / basic resolution (usually 800 x 600), so something like that would be nice. Workaround: Get to TTY and reboot
removing the json while kwin_wayland is not running works. I just tested it, afterwards the position of my screens were reset. Alternatively you can change settings with kscreen-doctor while kwin_wayland is running (might have to set WAYLAND_DISPLAY environment variable) when doing from outside the session > So far as I know, does KWin violate the fundamental UNIX principle that everything is editable in the form of a text file. This is desktop Linux not UNIX
> removing the json while kwin_wayland is not running works. Sounds awesome. How about a button that does exactly that?
I also don't understand why I can't access and modify the display settings of an external display, unless they are plugged in. Is it maybe possible to have KScreen optionally showing all the displays, it was connected to - similarly as it is with WLAN and Bluetooth connections - and allow me to alter its settings before I plug it in? I think its not properly understood, that this is a critical issue, that renders the hardware of people effectively useless, and that happens more often than probably believed. Just sending casuals to the tty, because the team has broken decade old Linux traditions for unknown reasons, seems like a really bad design decision. It cant be that we send users into broken hardware, without offering a proper solution for that.
>I also don't understand why I can't access and modify the display settings of an external display, unless they are plugged in. The UX would be too confusing. One thing coming in future releases is a "safe mode" available at the login manager screen, this will bypass your current user settings and provide a button to delete all kwin+plasma configs.
That would surely be an improvement. Is there already an issue open, that I can follow?