Arch Linux

mcloaked

Member

From: Yorkshire, UK

Registered: 2012-02-02

Posts: 1,240

SDDM Plasma 6 not powersaving

After the transition to Plasma 6 I thought I would try to switch sddm to Wayland.  Simply adding the file 10-wayland.conf to /etc/sddm.conf.d/ with content:

[General]
DisplayServer=wayland
GreeterEnvironment=QT_WAYLAND_SHELL_INTEGRATION=layer-shell,XKB_DEFAULT_LAYOUT=gb

[Wayland]
CompositorCommand=kwin_wayland --drm --no-lockscreen --no-global-shortcuts --locale1

Does go to the sddm greeter when the sddm service starts, and as far as I can tell is running under Wayland. It then allows a Plasma(Wayland) session to start on login from the greeter.

However there are two issues that seem to happen that I was unhappy with and led me to removing the above file to go back to default. One is that the size of the icons and fonts on the greeter are larger than when starting sddm without the Wayland config file, and I couldn't easily find how to fix that (my systems are not using HiDpi and I tried on two separate machines both having the same issue with greeter display size.

The second issue is more important, and involves the behaviour for timeout with sddm greeter on the screen but nobody logs in.  Without the Wayland settings the monitor will go into powersave mode after some period, and will power back on at any time the mouse is moved or a key is pressed on the keyboard - which is expected and normal behaviour. On the other hand running sddm Wayland, this does not happen and the screen remains powered on indefinitely, which is not acceptable for a machine that is left permanently running. Of course if a user logs in then the power management behaviour follows that set by the user logged in to the Plasma Desktop, but without a user logged in it is important to be able to also have the greet screen timeout to powersave the monitor.

Does anyone know of a workaround to make the powersave initiate on timeout with sddm running under Wayland?

One final comment is that if the file /etc/sddm.conf.d/10-wayland.conf is renamed /etc/sddm.conf.d/10-wayland.conf.prev I would have expected that sddm would not parse that file when starting up, but it seems there is no filter and parsing of the filenames in that directory and the file with the .prev suffix still leads to sddm running in Wayland, when I would expect it to revert to the original behaviour.

Last edited by mcloaked (2024-03-19 09:16:56)

---

Mike C

mcloaked

Member

From: Yorkshire, UK

Registered: 2012-02-02

Posts: 1,240

Re: SDDM Plasma 6 not powersaving

I have placed an upstream bug report at https://github.com/sddm/sddm/issues/1897

---

Mike C

V1del

Forum Moderator

Registered: 2012-10-16

Posts: 21,785

Re: SDDM Plasma 6 not powersaving

That would be something to implement on KWin lest you want to pull in the entire powerdevil baseline. That's the good thing about Xorg, a lot of these common things one "expects" to be there have been implemented centrally in the xorg server.

It might make more sense to just use Weston as the compositor here if you're bent on avoiding SDDM running xorg, seeing it's intention as a standalone compositor it has stuff like idle time implemented with a simple ini config.

FWIW random curiosity, there's an MR using logind directly with SDDM: https://github.com/sddm/sddm/pull/1878

Last edited by V1del (2024-03-19 16:56:53)

mcloaked

Member

From: Yorkshire, UK

Registered: 2012-02-02

Posts: 1,240

Re: SDDM Plasma 6 not powersaving

Thanks for that link. Though in the case of a desktop acting as both a server needing 24/7 operation, as well as allowing users to work with a Plasma session, then if nobody is logged in then suspend of course would stop the server activity so in that case simply powersaveing the monitor is all that is required. I will look at your suggestion of running sddm with Weston rather than Kwin and see what behavior is available for the timeout with no users logged in.

Edit: Following on from your link there is also some recent movement a couple of weeks ago at https://github.com/sddm/sddm/issues/1302 even though it was started a few years ago.

Edit2:  It seems this was a topic in another section of the Arch forums a few months ago - https://bbs.archlinux.org/viewtopic.php?id=291481

Edit3: In this report a user found last year that Weston in SDDM Wayland did not go into powersave: https://github.com/sddm/sddm/issues/1417

Last edited by mcloaked (2024-03-19 19:22:45)

---

Mike C

mcloaked

Member

From: Yorkshire, UK

Registered: 2012-02-02

Posts: 1,240

Re: SDDM Plasma 6 not powersaving

After the github issue was closed upstream I have posted at: https://bugs.kde.org/show_bug.cgi?id=484015

---

Mike C