Plasma Login Manager stutters / freezes / pauses

SparkyEE · September 4, 2026, 12:31pm

Recent new development as of 9/4.

When attempting to enter password on plasma-login-manager, the screen freezes for a few seconds every few seconds. This makes it extremely hard to log in as key strokes are not registered when screen is temporarily frozen.

I have worked around this issue by switching back to SDDM (hopefully temporarily).
Any thoughts?

I’m running the latest CachyOS,
Plasma 6.7.4
KDE Framework 6.29.0
Qt 6.11.2
Kernel 7.2.3-1
Graphics Platform: Wayland
CPU: Radeon RX 9070XT

barryascott · September 4, 2026, 2:06pm

Check the system journal for errors at the time you are trying to login.
What do you find?

truongan · September 23, 2026, 5:46am

I’ve just switched to plasma login manager today (was on gdm and sddm previously). A quick look at

journalctl -xb | grep ERROR show

lots of repeating lines

kernel: amdgpu 0000:2d:00.0: [drm] *ERROR* Unsupported screen format RA24 little-endian (0x34324152)

I’m using Radeon RX 9060XT. So maybe some problem between plasma login manger and amdgpu driver perhaps ???

nite_route · September 23, 2026, 8:28am

that amdgpu Unsupported screen format RA24 line matches what truongan pasted. plasma login manager is asking for a pixel format the driver is rejecting, so the greeter freezes in short bursts while you type.

next freeze, pull:
journalctl -b -u plasma-login-manager --no-pager | tail -80
dmesg | grep -iE ‘amdgpu|drm’ | tail -40

say kernel + mesa versions too.

staying on sddm is fine until that format mismatch gets sorted.

truongan · September 23, 2026, 2:15pm

When the freeze happened I was on

Linux version 7.2.6-zen3-xanmod1-1-edge (makepkg@archlinux) (gcc (GCC) 16.2.1 20260810, GNU ld (GNU Binutils) 2.47) #1 SMP PREEMPT_DYNAMIC

-u plasma-login-manager return – No entries, but -u plasmalogin does.

journalctl -b -1 -u plasmalogin --no-pager | tail -80
Thg 9 22 17:38:55 anhomepc plasmalogin[1606]: Adding new display...
Thg 9 22 17:38:55 anhomepc plasmalogin[1606]: Using VT 1
Thg 9 22 17:38:55 anhomepc plasmalogin[1606]: Display server started.
Thg 9 22 17:38:55 anhomepc plasmalogin[1606]: Socket server starting...
Thg 9 22 17:38:55 anhomepc plasmalogin[1606]: Socket server started.
Thg 9 22 17:38:55 anhomepc plasmalogin[1606]: Greeter starting...
Thg 9 22 17:38:55 anhomepc plasmalogin-helper[1645]: Detected locale "C" with character encoding "ANSI_X3.4-1968", which is not UTF-8.
                                                     Qt depends on a UTF-8 locale, and has switched to "C.UTF-8" instead.
                                                     If this causes problems, reconfigure your locale. See the locale(1) manual
                                                     for more information.
Thg 9 22 17:38:55 anhomepc plasmalogin-helper[1645]: [PAM] Starting...
Thg 9 22 17:38:55 anhomepc plasmalogin-helper[1645]: [PAM] Authenticating...
Thg 9 22 17:38:55 anhomepc plasmalogin-helper[1645]: [PAM] returning.
Thg 9 22 17:38:55 anhomepc plasmalogin-helper[1645]: pam_unix(plasmalogin-greeter:session): session opened for user plasmalogin(uid=943) by (uid=0)
Thg 9 22 17:38:56 anhomepc plasmalogin-helper[1645]: Starting Wayland user session: "/usr/share/plasmalogin/scripts/wayland-session" "/usr/bin/startplasma-login-wayland"
Thg 9 22 17:38:56 anhomepc plasmalogin[1606]: Greeter session started successfully
Thg 9 22 17:38:58 anhomepc plasmalogin[1606]: Message received from greeter: Connect
Thg 9 22 17:39:41 anhomepc plasmalogin[1606]: Message received from greeter: Login
Thg 9 22 17:39:41 anhomepc plasmalogin[1606]: start auth user true "/usr/lib/plasma-dbus-run-session-if-needed /usr/bin/startplasma-wayland"
Thg 9 22 17:39:41 anhomepc plasmalogin[1606]: Session "/usr/share/wayland-sessions/plasma.desktop" selected, command: "/usr/lib/plasma-dbus-run-session-if-needed /usr/bin/startplasma-wayland" for VT 2 "wayland"
Thg 9 22 17:39:41 anhomepc plasmalogin-helper[2288]: Detected locale "C" with character encoding "ANSI_X3.4-1968", which is not UTF-8.
                                                     Qt depends on a UTF-8 locale, and has switched to "C.UTF-8" instead.
                                                     If this causes problems, reconfigure your locale. See the locale(1) manual
                                                     for more information.
Thg 9 22 17:39:41 anhomepc plasmalogin-helper[2288]: [PAM] Starting...
Thg 9 22 17:39:41 anhomepc plasmalogin-helper[2288]: [PAM] Authenticating...
Thg 9 22 17:39:41 anhomepc plasmalogin-helper[2288]: [PAM] Preparing to converse...
Thg 9 22 17:39:41 anhomepc plasmalogin-helper[2288]: [PAM] Conversation with 1 messages
Thg 9 22 17:39:41 anhomepc plasmalogin-helper[2288]: pam_unix(plasmalogin:auth): authentication failure; logname= uid=0 euid=0 tty= ruser= rhost=  user=truongan
Thg 9 22 17:39:42 anhomepc plasmalogin-helper[2288]: [PAM] authenticate: Authentication failure
Thg 9 22 17:39:42 anhomepc plasmalogin-helper[2288]: [PAM] returning.
Thg 9 22 17:39:42 anhomepc plasmalogin-helper[2288]: [PAM] Asked to close the session but it wasn't previously open
Thg 9 22 17:39:42 anhomepc plasmalogin[1606]: Authentication error: PLASMALOGIN::Auth::ERROR_AUTHENTICATION "Authentication failure"
Thg 9 22 17:39:42 anhomepc plasmalogin[1606]: Authentication for user  ""  failed
Thg 9 22 17:39:42 anhomepc plasmalogin-helper[2288]: [PAM] Ended.
Thg 9 22 17:39:42 anhomepc plasmalogin[1606]: Auth: plasmalogin-helper exited with 1
Thg 9 22 17:40:08 anhomepc plasmalogin[1606]: Message received from greeter: Login
Thg 9 22 17:40:08 anhomepc plasmalogin[1606]: start auth user true "/usr/lib/plasma-dbus-run-session-if-needed /usr/bin/startplasma-wayland"
Thg 9 22 17:40:08 anhomepc plasmalogin[1606]: Session "/usr/share/wayland-sessions/plasma.desktop" selected, command: "/usr/lib/plasma-dbus-run-session-if-needed /usr/bin/startplasma-wayland" for VT 2 "wayland"
Thg 9 22 17:40:08 anhomepc plasmalogin-helper[2295]: Detected locale "C" with character encoding "ANSI_X3.4-1968", which is not UTF-8.
                                                     Qt depends on a UTF-8 locale, and has switched to "C.UTF-8" instead.
                                                     If this causes problems, reconfigure your locale. See the locale(1) manual
                                                     for more information.
Thg 9 22 17:40:08 anhomepc plasmalogin-helper[2295]: [PAM] Starting...
Thg 9 22 17:40:08 anhomepc plasmalogin-helper[2295]: [PAM] Authenticating...
Thg 9 22 17:40:08 anhomepc plasmalogin-helper[2295]: [PAM] Preparing to converse...
Thg 9 22 17:40:08 anhomepc plasmalogin-helper[2295]: [PAM] Conversation with 1 messages
Thg 9 22 17:40:08 anhomepc plasmalogin-helper[2295]: gkr-pam: unable to locate daemon control file
Thg 9 22 17:40:08 anhomepc plasmalogin-helper[2295]: gkr-pam: stashed password to try later in open session
Thg 9 22 17:40:08 anhomepc plasmalogin-helper[2295]: pam_kwallet5(plasmalogin:auth): pam_kwallet5: pam_sm_authenticate
Thg 9 22 17:40:08 anhomepc plasmalogin-helper[2295]: [PAM] returning.
Thg 9 22 17:40:08 anhomepc plasmalogin[1606]: Authentication for user  "truongan"  successful
Thg 9 22 17:40:08 anhomepc plasmalogin-helper[2295]: pam_kwallet5(plasmalogin:setcred): pam_kwallet5: pam_sm_setcred
Thg 9 22 17:40:08 anhomepc plasmalogin-helper[2295]: pam_unix(plasmalogin:session): session opened for user truongan(uid=1000) by truongan(uid=0)
Thg 9 22 17:40:09 anhomepc plasmalogin-helper[2295]: pam_env(plasmalogin:session): deprecated reading of user environment enabled
Thg 9 22 17:40:09 anhomepc plasmalogin-helper[2295]: gkr-pam: unlocked login keyring
Thg 9 22 17:40:09 anhomepc plasmalogin-helper[2295]: pam_kwallet5(plasmalogin:session): pam_kwallet5: pam_sm_open_session
Thg 9 22 17:40:09 anhomepc plasmalogin-helper[2295]: Starting Wayland user session: "/usr/share/plasmalogin/scripts/wayland-session" "/usr/lib/plasma-dbus-run-session-if-needed /usr/bin/startplasma-wayland"
Thg 9 22 17:40:09 anhomepc plasmalogin[1606]: Session started true
Thg 9 22 17:40:14 anhomepc plasmalogin[1606]: Greeter stopping...
Thg 9 22 17:40:14 anhomepc plasmalogin[1606]: Auth: plasmalogin-helper exited with 255
Thg 9 22 17:40:14 anhomepc plasmalogin[1606]: Greeter stopped. PLASMALOGIN::Auth::HelperExitStatus(255)
Thg 9 23 06:35:02 anhomepc plasmalogin[1606]: Authentication error: PLASMALOGIN::Auth::ERROR_INTERNAL "Process crashed"
Thg 9 23 06:35:02 anhomepc plasmalogin[1606]: Auth: plasmalogin-helper (--socket /tmp/plasmalogin-auth-bf383a7f-dbb0-4173-8d53-a635b0712a9a --id 1 --start /usr/lib/plasma-dbus-run-session-if-needed /usr/bin/startplasma-wayland --user truongan) crashed (signal 1)
Thg 9 23 06:35:02 anhomepc plasmalogin[1606]: Authentication error: PLASMALOGIN::Auth::ERROR_INTERNAL "Process crashed"
Thg 9 23 06:35:02 anhomepc plasmalogin[1606]: Socket server stopping...
Thg 9 23 06:35:02 anhomepc plasmalogin[1606]: Socket server stopped.
Thg 9 23 06:35:02 anhomepc plasmalogin[1606]: Removing display PLASMALOGIN::Display(0x7f4830009060) ...
Thg 9 23 06:35:02 anhomepc plasmalogin[1606]: Adding new display...
Thg 9 23 06:35:02 anhomepc systemd[1]: Stopping Plasma Login Manager...
Thg 9 23 06:35:03 anhomepc plasmalogin[1606]: Using VT 1
Thg 9 23 06:35:03 anhomepc plasmalogin[1606]: Display server started.
Thg 9 23 06:35:03 anhomepc plasmalogin[1606]: Socket server starting...
Thg 9 23 06:35:03 anhomepc plasmalogin[1606]: Socket server started.
Thg 9 23 06:35:03 anhomepc plasmalogin[1606]: Greeter starting...
Thg 9 23 06:35:03 anhomepc plasmalogin[1606]: Socket server stopping...
Thg 9 23 06:35:03 anhomepc plasmalogin[1606]: Socket server stopped.
Thg 9 23 06:35:03 anhomepc plasmalogin[1606]: Auth: plasmalogin-helper (--socket /tmp/plasmalogin-auth-bf383a7f-dbb0-4173-8d53-a635b0712a9a --id 4 --start /usr/bin/startplasma-login-wayland --user plasmalogin --greeter) crashed (signal 15)
Thg 9 23 06:35:03 anhomepc systemd[1]: plasmalogin.service: Deactivated successfully.
Thg 9 23 06:35:03 anhomepc systemd[1]: Stopped Plasma Login Manager.

I was on archlinux, so mesa version was:

pacman -Qs mesa
local/glu 9.0.3-3
    Mesa OpenGL utility library
local/lib32-mesa 1:26.2.3-1
    Open-source OpenGL drivers - 32-bit
local/lib32-vulkan-mesa-implicit-layers 1:26.2.3-1
    Mesa's implicit Vulkan layers - 32-bit
local/mesa 1:26.2.3-1
    Open-source OpenGL drivers
local/mesa-utils 9.0.0-7
    Essential Mesa utilities
local/vulkan-mesa-implicit-layers 1:26.2.3-1
    Mesa's implicit Vulkan layers

and

❯ pacman -Qs plasma-login
local/plasma-login-manager 6.7.5-1 (plasma)
    Plasma Login Manager

More over, earlier today I upgraded to

Linux anhomepc 7.2.7-zen3-xanmod1-1-edge #1 SMP PREEMPT_DYNAMIC

and things seem to have improved on its own.

I’m still new to KDE and thus pretty clueless, just hope this can help.