Created attachment 114436 [details]
xrandr output from GPD Win 2
I find that "panel orientation" output property is not supported in KScreen. Linux kernel include quirks for several devices with hint about panel position: https://github.com/torvalds/linux/blob/master/drivers/gpu/drm/drm_panel_orientation_quirks.c
For example on GPD Win 1 and GPD Win 2 panels mounted as portrait, so kernel include hint about that:
xrandr output from GPD Win 2 is attached (look for "panel orientation" line).
This hint is taken into account by text console and by Gnome Shell, but seems like ignored by KScreen.
Fixed by Xaver Hugl with https://invent.kde.org/plasma/kwin/-/commit/65e886cde2387c7d2ad3247c3b77e6b9fb9514e5 in Plasma 5.27!
BTW, it is possible to tell the kernel to set a specific panel orientation for specific display ports, even if the hardware doesn't do it by itself - for example, I have an external monitor that is vertically oriented, but the hardware doesn't know about it (I'm guessing the Dell desktop monitor doesn't have an orientation sensor...), so I can tell the kernel - using the kernel command line - "please note that this connector it plugged into a vertically oriented screen".
To do that, add a `video` parameter to the kernel command line (for example, by editing /etc/default/grub in a Debian based OS), which is formatted as such: `video=<connector>:panel_orientation=<orientation>`, where "orientation" is a valid value as documented in the kernel framebuffer documentation: https://docs.kernel.org/fb/modedb.html. For example, my setup is `video=DP-3:panel_orientation=left_side_up` (the connector name comes from looking under /sys/class/drm and removing the card identifier; the kscreen KCM used to show the connector name, but it does not anymore).
Unfortunately, while this works well for plymouth's boot graphics, it doesn't actually changes the text VT orientation, nor SDDM's display configuration - which is the main thing I was trying to achieve - SDDM doesn't support vertical screens and it is always annoying.
KWin and KScreen aren't running yet when SDDM is active, so this fix wouldn't automatically fix anything on the SDDM login screen.. Nevertheless, on Wayland, you can sync your display layout--including orientation--to SDDM using the "Apply Plasma Settings" feature of the SDDM KCM. On X11 this isn't available.
(In reply to Nate Graham from comment #3)
> on Wayland, you can sync your display layout--including orientation--to SDDM
> using the "Apply Plasma Settings" feature of the SDDM KCM. On X11 this isn't
I have tried that, and I don't see it working.
I tried to find how to configure SDDM (even manually, possibly by editing things under /etc), but I can't find any appropriate documentation, example files or even code (in github.com/sddm/sddm) to support this. But all this is probably for another bug.
Indeed it is. :)