Login screen had no option to change session type i.g. X11 instead of Wayland

Ask Fedora
1

The overall question is how do I get a login manager working again when I get a black screen after booting into the Fedora 44 install after trying to enable SDDM login manager?

This quote is skippable; just kind of about me and what I was attempting to accomplish

Hi I’m very new to Linux. I have googled, and tried to search documentation and these forums to fix where I am now, but I probably don’t have the knowledge to search the right thing.

*I installed Fedora Wayland. OMG I loved it! *

I tried to get 4k@120hz from a DP1.4a to a Samsung S95B; which forced me to do a DP to HDMI conversion since my GTX 2070 Super XC only has an HDMI 2.0b. With the conversion cable the screen would not stop flickering every 10-20 seconds. I have tested the cable on a windows 11 install and I get 4k@120hz completely stable. After lots of troubleshooting I wanted to try an X11 session.

Specs:

  • Fedora 44, Wayland, KDE Plasma installed to NVMe from USB.
  • Nvidia GTX 2070 Super XC - HDMI 2.0b (stable at 4k@60hz), DP 1.4a
  • Monitor/TV is a Samsung S95B. It does not have a DP connection, so I am using a unidirectional cable that plugs into the GPU DP and the tv’s HDMI. A link to the cable is in the quoted text above.

What was I trying to accomplish that lead me to attempt switching to X11:
I am trying to get 4k@120hz on my tv. Windows 11 is able to use the same DP-to-HDMI conversion cable to provide 4k@120hz HDR VRR with no problems. I believe this demonstrates the cable is functional. When using the cable with Fedora, I experienced flickering periodically.

EDIT: I provided this information in posts below and thought it would be good to add in the OP

I was able to find a handful of posts (not these forums) with people suggesting switching to X11 since it is a more mature display server. A handful of people replied that this fixed or greatly improved the flickering.

I confirmed X11 was installed. However there was no gear icon at my login screen to change my session type. So that lead me to think I needed to switch to a different login manager.

I apologize if there would be a better way to present this and would be happy to clean it up with some guidance. I have no programming experience.

Checked for SDDM:
Entered

systemctl status sddm --no-pager

Result

sddm.service ... disabled
Active: inactive (dead)

Checked Display Manager
Entered

systemctl status display-manager --no-pager

Result

● plasmalogin.service - Plasma Login Manager
Active: active (running)

Searched session configuration
Entered

grep -RniE 'wayland|x11|session|xsessions' /etc/plasmalogin /usr/lib/systemd/system/plasmalogin.service 2>/dev/null

Result

/etc/plasmalogin/wayland-session:2:# wayland-session - run as user

plasmalogin not showing X11

Why is plasmalogin acting a bit strange
Entered

rpm -ql plasmalogin | sort

Result

package plasmalogin is not installed

Was not sure what to make of that.

Lets Try to switch to SDDM

rpm -qa | grep -i '^sddm'

Result

sddm-wayland-sway-0.4.3-3.fc44.noarch
sddm-0.21.0-13.fc44.x86_64

Okay SDDM is installed, lets disable plasmalogin

sudo systemctl disable plasmalogin.service
sudo systemctl enable sddm.service

Result

Removed '/etc/systemd/system/display-manager.service'.
Created symlink '/etc/systemd/system/display-manager.service' → '/usr/lib/systemd/system/sddm.service'.
  • I then rebooted
  • bootmanager appeared
  • selected my Fedora install
  • Blank black screen

How should I go about recovering? Are there any other details I should provide?

2

I believe that plasmalogin is wayland only.

What is broken in wayland that you think using x11 will fix?

3

Do you have nvidia? Have you installed the rpmfusion nvidia drivers?

4

I have seen a few topics from google searches that when people have display flicker in wayland it’s worth trying an X11 session to see if the problem is wayland related and narrow down what is not working. Replies in those topics had people reporting that an X11 session did improve things. Personally I don’t have a theory about what it might fix. Seemed like a troubleshooting step worth trying.

5

Specs:

  • Fedora 44, Wayland, KDE Plasma installed to NVMe from USB.
  • Nvidia GTX 2070 Super XC - HDMI 2.0b (stable at 4k@60hz), DP 1.4a
  • Monitor/TV is a Samsung S95B. It does not have a DP connection, so I am using a unidirectional cable that plugs into the GPU DP and the tv’s HDMI. The cable

I have an Nvidia GTX 2070 Super XC. The HDMI port on my GPU is 2.0b, so I cannot use that to get 4k@120hz, I must use a displayport 1.4a. With HDMI I was stable at 1440p@120hz. DP is not stable for the same, and oddly enough moving down to 60hz in any resolution made the flickering worse. I am unsure how I might confirm that all 3 of the DP ports on my GPU are not damaged, but they all gave the same result.

I did install the rpmfusion drivers. I started on 610.43.03. I removed 610 and installed 580.173.02 and got the same flickering. To my understanding that was the most recent, most similar set of drivers that were available to try. I believe this step demonstrated that the flickering isn’t driver related; perhaps not definitively.

Since I have come across something called Gamescope; but am not sure that would help here.

While sitting idle there would be periodic flickering. I found that window animations would trigger the flicker. Turning off animations and maximizing a window via the maximize button would more often than not, not cause a flicker. Dragging a window to the top of the screen to maximize in that fashion would always cause the flicker. Switching the window that was my focus would usually cause a flicker.

I am going to add some details to the original post that I have provided here.

6

Fedora does not ship the Plasma X11 session anymore, though I think it’s still available in the repos (just not supported by the KDE special interests group).

Though note that KDE developers are dropping the X11 session in Plasma 6.8, which will release in a couple of months.

7

Hmm okay. I’m wondering if I should give gnome a shot? Maybe I’ll get a stable screen there even in wayland or does X11 ship with gnome? Maybe install a previous version of Fedora that will support X11 with Plasma?

I’ll do some reading to see if I can figure out what path I should take but would welcome a recommendation. I’ll see if I can dig a bit deeper on getting 4k@120hz also. But 1440p@120 through HDMI will be completely fine if I don’t find any good options.

8

Gnome is currently on version 50, they dropped X11 support in the last release.

Currently if you want an X11 session experience, you need to go for something like Cinnamon, MATE, or XFCE.

9

Did you ask for help with the flickering here? Maybe start a new topin on the screen tearing and see if people help can debug that with you?

I would not expect much difference going to X11 (expect that X11 screen tears).

10

No need to change the Fedora version, you can just do dnf install plasma-workspace-x11.

Hadn’t you already done this though? (You said “I confirmed X11 was installed.”)

As @novafunc said, this will cease to be supported in Plasma 6.8, so it’s a short-term solution at best.

11

You may also need to install a different greeter for sddm, for example sddm-x11. That would conflict with the currently installed greeter, so you have to allow dnf to remove that.

12

I had a problem with connecting to a 4k TV as a monitor when I was adding a KVM switch to enable 3 different computers to be managed with a single keyboard/monitor/mouse config.

It turned out that I had to upgrade the HDMI cable between the computer and the KVM switch to the latest version that supported 8k video (HDMI 2.1) and then things just worked.

Is it possible that your cable that is DP → HDMI is not high enough quality to support the 4k signal?

I should not think that would be an issue since the cable you linked is also HDMI 2.1.

On my 4k TV I am only able to get a 30 Hz refresh rate that I think is specifically TV related.

I really suspect that the nvidia 2070 card is unable to support 120Hz refresh properly to that monitor and you may have a reliable display if you reduced that to 60Hz.

13

No. I actually hadn’t found these forums yet. Found them after I broke it. Even then I think I would have searched old topics to see how far I could get myself. So I could then come here and demonstrate that I really tried my best before asking other people for their time.

I appreciate the question as its forcing me to think about when I should ask for direction with this community.

  • If something is broken or buggy, I’ll search for discussions then I’ll ask for direction.

  • If I’m trying to do something new (not fix something broken) I’ll do my best to follow guides and research. If the path forward still seems sketchy I’ll make a post, layout my plan and and ask for feedback.

  • I need to get the BTRFS snapshot thing going. So if I do get impatient and break something I can fallback. That’s probably my mission for today. Any thoughts on which path to implementing that for my experience level would be appreciated.

-Also I’m doing a lot of playing around with system settings. Lots of things require me to select a new setting then mouse down to “Apply” to actually see what it does. Is there a keyboard shortcut for “Apply” can I make one? Would make testing all the system and widget options so much less painful.

14

Alt+A

15

I just threw the USB drive in and reinstalled from scratch. I kind of wanted to see how much more efficient I’d already be at getting to the same place. Much more efficient!

I’m just going to live with 1440p@120 for now, so no need to try the X11 session. Maybe the next Fedora update will fix it. But 1440p is completely tolerable. Maybe once I get Btrfs snapshots in place, and trying to get 4k@120 is like the last thing I can possibly do I’ll see if it’s something that has been solved or if people can help me troubleshoot it.

But for now I just want to get myself comfortably away from windows. When that happens. Fedora is going onto the main NVMe in the windows PC and I’ll have an HDMI 2.1 over there so 4k@120 should just work and I’ll probably install windows onto a separate SSD (since windows doesn’t break dual booting on updates) in case I ever need to use it. Then I’ll have this computer just sitting here ready to become a linux server for something that the rasp pi can’t handle.

16

Does that have Nvidia graphics too? If so, then yes HDMI 2.1 should just work.

On AMD graphics, HDMI 2.1 isn’t supported on Linux (licensing shenanigans - the patent holders prevent the use of HDMI 2.1 in an open source driver) so you need DP to get to the highest resolutions and refresh rates.

17

So the cable gives me 4k@120 flawless on windows I think 4k@144hz was stable too, but it caused some issues I didn’t want to deal with.

Linux is apparently a bit more ridged in its handling of the situation from what I have been able to find. Perhaps a different conversion cable would work, but it is just not worth it to me anymore. The cable will give me 1440p@120 with zero fuss and that’s fine. I’d rather have the responsive refresh rate than a higher resolution. Then once I’m confident Fedora can be my daily driver I’ll be installing it to my main hardware which has an HDMI 2.1 on the GPU. So the problem should take care of itself at that point.

18

Thank you! It’s working with system settings and some widget settings but not all widget settings seem to work. Still that’s a huge QOL thing to know.

19

Very much depends on whether the app in question has set up a shortcut key for that button or menu option.

Usually, if there’s a shortcut, it’s an underlined letter in the word (usually, but not always) hit with an Alt modifier; ergo:

image

20

You may find your gpu cannot do 4k@120Hz so no software fix would be possible.