sddm multi monitor - wayland

[Linubie]

Hi,

I have 2 monitors.

Primary is a PL2730H (center)
Secondary is a L227W (right)

I am using Plasma/KDE/kwin/Wayland

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 xrandr | grep -w connected
HDMI-A-2 connected 1680x1050+1920+0 (normal left inverted right x axis y axis) 474mm x 296mm
DP-3 connected primary 1920x1080+0+0 (normal left inverted right x axis y axis) 598mm x 336mm

But at login with sddm the secondary monitor (L227W) is always the one I have to type my passwort in.

As explained on the wiki I created the file in /etc/sddm/scripts/Xsetup
https://wiki.gentoo.org/wiki/SDDM#Multi ... figuration

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#!/bin/sh
# Xsetup - run as root before the login dialog appears

# ...

# First, set DP-3 as primary
xrandr --output DP-3 --auto --primary
# Second, HDMI-A-2 will be placed on right of DP-3
xrandr --output HDMI-A-2 --right-of DP-3 --noprimary

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ls X*
-rw-r--r-- 1 root root 245  7. Feb 21:45 Xsetup

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lspci | grep GA102
2b:00.0 VGA compatible controller: NVIDIA Corporation GA102 [GeForce RTX 3080] (rev a1)
2b:00.1 Audio device: NVIDIA Corporation GA102 High Definition Audio Controller (rev a1)

But unfortunately it does not change anything.

[Anon-E-moose]

X programs like xrandr won't work with wayland.

You could try wlr-randr

[flexibeast]

X programs like xrandr won't work with wayland.

You could try wlr-randr

However, as i understand it, SDDM doesn't necessarily use Wayland itself; the `DisplayServer` configuration variable can be set to `x11` or `x11-user`, for rootless X. (i don't use SDDM or KDE myself, but i would like the SDDM page on the wiki to be updated and improved; i've recently made some a few relatively limited changes, but it would be good if someone more familiar with SDDM could e.g. add stuff about Wayland.)

wlr-randr is for wlroots-based compositors, which Kwin isn't, but perhaps it somehow works anyway.

[Anon-E-moose]

*Disclaimer* I don't use sddm, never have, but...

Old versions of sddm started up an Xserver, whether for an X session or a wayland session (this was in the early adoption era of wayland)

New versions, AFAIK, don't need to start an Xserver, I would check the documtation for the specific version of sddm.

None the less, xrandr is an X app not a wayland one. wlr-randr serves the same purpose in the wayland ecosystem.

wlr-randr does not need roots, only wayland libs, should work on every compositor, though gnome and kde may have their own versions of it.
I don't use either, so just a guess.

[flexibeast]

New versions, AFAIK, don't need to start an Xserver, I would check the documtation for the specific version of sddm.

They don't indeed, though Wayland support via setting the `DisplayServer` config variable is still experimental, as per the the sddm.conf(5) man page:

DisplayServer=
Select the display server to use for the greeter. Valid values are:

x11: X server running as root.
x11-user: X server running as unprivileged user.
wayland: Wayland compositor as unprivileged user. (Experimental)

None the less, xrandr is an X app not a wayland one.

It is indeed, but if SDDM is running on top of X, doesn't that then mean that, prior to it starting a Wayland session, xrandr can be used to configure output?

wlr-randr serves the same purpose in the wayland ecosystem.

wlr-randr does not need roots, only wayland libs, should work on every compositor, though gnome and kde may have their own versions of it.

Wayland isn't so much about libraries as about protocols. (Wayland itself, of course, being a protocol, not a server.) In this case,as the wlr-randr(1) man page says at the beginning:

This utility requires the compositor to implement the wlr-output-management protocol.

KDE has its own output management protocol. To check if a compositor supports a particular protocol, one can use wayland-info(1); here's a shell function i've used to list the interfaces supported by the running compositor:

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wl-interfaces () {
	wayland-info | grep 'interface' | sed "s/interface: '\([^']*\)',.*version:  \([^,]*\),.*/\1 | \2/" | sort
}

[Anon-E-moose]

Sddm does not need Xserver to start a Wayland user session, by default, it uses the Xserver to run its greeter.
But sddm can be configured to run entirely under wayland. ,

[wjb]

Is xrandr really used if you have an NVidia card - the PC I'm using has two monitors off an NVidia card and I've never had xrandr set up on it.

Anyway, does the mouse move correctly between the primary and secondary monitors in SDDM, or do you have to move it past the outside edges. I suspect the latter, cos thats what I had when I switched over to Wayland session. Personally I just swapped over the video cables, rebooted and SDDM was fixed but Plasma was swapped - so fixed that in Plasma Settings.

[flexibeast]

Sddm does not need Xserver to start a Wayland user session, by default, it uses the Xserver to run its greeter.
But sddm can be configured to run entirely under wayland. ,

Er, yes, that's what i noted in my previous message, responding to you writing "New versions, AFAIK, don't need to start an Xserver" with "They don't indeed" (i.e. "Yes, they don't need to start an X server"), and then going on to mention being able to request Wayland support via the `DisplayServer` variable, quoting its description in the sddm.conf(5) man page?

My point was that, if Linubie chooses to use X to run the greeter, rather than using the experimental Wayland support, then i imagine xrandr could then be run by SDDM, via the `Xsetup` file noted in the OP, even if the session type that was subsequently selected via SDDM was a Wayland session, rather than X (and that this would then obviate the need to worry about whether or not Kwin supports the wlr-output-management protocol used by wlr-randr.)