sddm produces black screen, "Cannot create children", autologin works

Wild Penguin · 2016-09-19 16:44:54

Hi,

At some point (I'm not sure when, since I've been using autologin) sddm stopped working. Here "stopped working" means it will only produce a black screen. However, if I configure it to automatically log in my user, it works fine!

I've found several old threads about this kind of problem, and it seems re-occuring. However, in my case none of the solutions I've found applies - and, also according to my logs, the issue is different, to those I've found. I tried to add user sddm into "video" group, but that had no effect.

Actually, in my case there is nothing informative in sddm logs - here I am restarting sddm (without autologin):

Sep 19 19:30:02 ArkkiVille systemd[1]: Stopping Simple Desktop Display Manager...
Sep 19 19:30:02 ArkkiVille sddm[4378]: Signal received: SIGTERM
Sep 19 19:30:02 ArkkiVille sddm[4378]: Greeter stopping...
Sep 19 19:30:02 ArkkiVille sddm[4378]: Socket server stopping...
Sep 19 19:30:02 ArkkiVille sddm[4378]: Socket server stopped.
Sep 19 19:30:02 ArkkiVille sddm[4378]: Display server stopping...
Sep 19 19:30:02 ArkkiVille sddm[4378]: Display server stopped.
Sep 19 19:30:02 ArkkiVille sddm[4378]: Running display stop script  "/usr/share/sddm/scripts/Xstop"
Sep 19 19:30:02 ArkkiVille sddm[4378]: Greeter stopping...
Sep 19 19:30:02 ArkkiVille sddm[4378]: QProcess: Destroyed while process ("/usr/lib/sddm/sddm-helper") is still running.
Sep 19 19:30:02 ArkkiVille systemd[1]: Stopped Simple Desktop Display Manager.

/etc/sddm.conf:

$ cat /etc/sddm.conf
[Autologin]
Relogin=false
# Session=plasma.desktop
# User=ville

[General]
EnableHiDPI=true
HaltCommand=/usr/bin/systemctl poweroff
InputMethod=
Numlock=none
RebootCommand=/usr/bin/systemctl reboot

[Theme]
Current=maldives
CursorTheme=breeze_cursors
DisableAvatarsThreshold=7
EnableAvatars=true
FacesDir=/usr/share/sddm/faces
ThemeDir=/usr/share/sddm/themes

[Users]
DefaultPath=/bin:/usr/bin:/usr/local/bin
HideShells=
HideUsers=
MaximumUid=60000
MinimumUid=1000
RememberLastSession=true
RememberLastUser=true

[Wayland]
SessionCommand=/usr/share/sddm/scripts/wayland-session
SessionDir=/usr/share/wayland-sessions
SessionLogFile=.local/share/sddm/wayland-session.log

[X11]
DisplayCommand=/usr/share/sddm/scripts/Xsetup
DisplayStopCommand=/usr/share/sddm/scripts/Xstop
MinimumVT=1
ServerArguments=-nolisten tcp
ServerPath=/usr/bin/X
SessionCommand=/usr/share/sddm/scripts/Xsession
SessionDir=/usr/share/xsessions
SessionLogFile=.local/share/sddm/xorg-session.log
UserAuthFile=.Xauthority
XauthPath=/usr/bin/xauth
XephyrPath=/usr/bin/Xephyr

Last edited by Wild Penguin (2016-09-29 14:29:19)

Wild Penguin · 2016-09-19 16:58:57

I was only assuming that -u sddm would reproduce the relevant from journalctl - but apparently it doesn't:

Sep 19 19:47:59 ArkkiVille sudo[6401]: pam_unix(sudo:session): session opened for user root by ville(uid=0)
Sep 19 19:47:59 ArkkiVille systemd[1]: Started Simple Desktop Display Manager.
Sep 19 19:47:59 ArkkiVille sudo[6401]: pam_unix(sudo:session): session closed for user root
Sep 19 19:47:59 ArkkiVille sddm[6404]: Initializing...
Sep 19 19:47:59 ArkkiVille sddm[6404]: Starting...
Sep 19 19:47:59 ArkkiVille sddm[6404]: Adding new display on vt 1 ...
Sep 19 19:47:59 ArkkiVille sddm[6404]: Display server starting...
Sep 19 19:47:59 ArkkiVille sddm[6404]: Running: /usr/bin/X -nolisten tcp -auth /var/run/sddm/{34124818-fcf0-46c7-be8c-3d7208383b54} -background none -noreset -displayfd 18 vt1
Sep 19 19:47:59 ArkkiVille kernel: nvidia-modeset: Allocated GPU:0 (GPU-f13b272c-a66f-d544-f3f9-ede1ba0a0e9d) @ PCI:0000:01:00.0
Sep 19 19:47:59 ArkkiVille kernel: snd_hda_codec_hdmi hdaudioC1D0: HDMI: invalid ELD data byte 2
Sep 19 19:47:59 ArkkiVille sddm[6404]: Running display setup script  "/usr/share/sddm/scripts/Xsetup"
Sep 19 19:47:59 ArkkiVille sddm[6404]: Display server started.
Sep 19 19:47:59 ArkkiVille sddm[6404]: Socket server starting...
Sep 19 19:47:59 ArkkiVille sddm[6404]: Socket server started.
Sep 19 19:47:59 ArkkiVille sddm[6404]: Greeter starting...
Sep 19 19:47:59 ArkkiVille sddm[6404]: Adding cookie to "/var/run/sddm/{34124818-fcf0-46c7-be8c-3d7208383b54}"
Sep 19 19:47:59 ArkkiVille sddm-helper[6411]: [PAM] Starting...
Sep 19 19:47:59 ArkkiVille sddm-helper[6411]: [PAM] Authenticating...
Sep 19 19:47:59 ArkkiVille sddm-helper[6411]: [PAM] returning.
Sep 19 19:47:59 ArkkiVille sddm-helper[6411]: pam_unix(sddm-greeter:session): session opened for user sddm by (uid=0)
Sep 19 19:47:59 ArkkiVille systemd[1]: Created slice User Slice of sddm.
Sep 19 19:47:59 ArkkiVille systemd[1]: Starting User Manager for UID 617...
Sep 19 19:47:59 ArkkiVille systemd-logind[494]: New session c8 of user sddm.
Sep 19 19:47:59 ArkkiVille systemd[1]: Started Session c8 of user sddm.
Sep 19 19:47:59 ArkkiVille systemd[6413]: pam_unix(systemd-user:session): session opened for user sddm by (uid=0)
Sep 19 19:47:59 ArkkiVille systemd[6413]: Reached target Paths.
Sep 19 19:47:59 ArkkiVille systemd[6413]: Starting D-Bus User Message Bus Socket.
Sep 19 19:47:59 ArkkiVille systemd[6413]: Reached target Timers.
Sep 19 19:47:59 ArkkiVille systemd[6413]: Listening on Sound System.
Sep 19 19:47:59 ArkkiVille systemd[6413]: Listening on D-Bus User Message Bus Socket.
Sep 19 19:47:59 ArkkiVille systemd[6413]: Reached target Sockets.
Sep 19 19:47:59 ArkkiVille systemd[6413]: Reached target Basic System.
Sep 19 19:47:59 ArkkiVille systemd[6413]: Reached target Default.
Sep 19 19:47:59 ArkkiVille systemd[6413]: Startup finished in 8ms.
Sep 19 19:47:59 ArkkiVille systemd[1]: Started User Manager for UID 617.
Sep 19 19:47:59 ArkkiVille sddm[6404]: Greeter session started successfully
Sep 19 19:47:59 ArkkiVille sddm-greeter[6418]: High-DPI autoscaling Enabled
Sep 19 19:47:59 ArkkiVille sddm-greeter[6418]: Reading from "/usr/share/xsessions/kodi.desktop"
Sep 19 19:47:59 ArkkiVille sddm-greeter[6418]: Reading from "/usr/share/xsessions/plasma-mediacenter.desktop"
Sep 19 19:47:59 ArkkiVille sddm-greeter[6418]: Reading from "/usr/share/xsessions/plasma.desktop"
Sep 19 19:47:59 ArkkiVille sddm-greeter[6418]: Reading from "/usr/share/wayland-sessions/plasmawayland.desktop"
Sep 19 19:47:59 ArkkiVille sddm-greeter[6418]: Reading from "/usr/share/wayland-sessions/weston.desktop"
Sep 19 19:47:59 ArkkiVille sddm-greeter[6418]: Connected to the daemon.
Sep 19 19:47:59 ArkkiVille sddm[6404]: Message received from greeter: Connect
Sep 19 19:47:59 ArkkiVille sddm-greeter[6418]: Loading file:///usr/share/sddm/themes/breeze/Main.qml...
Sep 19 19:47:59 ArkkiVille sddm-greeter[6418]: QObject: Cannot create children for a parent that is in a different thread.
                                               (Parent is SDDM::GreeterApp(0x7ffe83dc53d0), parent's thread is QThread(0x1752930), current thread is QThread(0x1b27480)
Sep 19 19:47:59 ArkkiVille sddm-greeter[6418]: QObject: Cannot create children for a parent that is in a different thread.
                                               (Parent is SDDM::GreeterApp(0x7ffe83dc53d0), parent's thread is QThread(0x1752930), current thread is QThread(0x1b27480)
Sep 19 19:47:59 ArkkiVille sddm-greeter[6418]: QObject: Cannot create children for a parent that is in a different thread.
                                               (Parent is SDDM::GreeterApp(0x7ffe83dc53d0), parent's thread is QThread(0x1752930), current thread is QThread(0x1b27480)
Sep 19 19:47:59 ArkkiVille sddm-greeter[6418]: QObject::installEventFilter(): Cannot filter events for objects in a different thread.
Sep 19 19:47:59 ArkkiVille sddm-greeter[6418]: QObject: Cannot create children for a parent that is in a different thread.
                                               (Parent is SDDM::GreeterApp(0x7ffe83dc53d0), parent's thread is QThread(0x1752930), current thread is QThread(0x1b27480)
Sep 19 19:47:59 ArkkiVille systemd[6413]: Started D-Bus User Message Bus.
Sep 19 19:48:00 ArkkiVille sddm-greeter[6418]: QObject: Cannot create children for a parent that is in a different thread.
                                               (Parent is SDDM::GreeterApp(0x7ffe83dc53d0), parent's thread is QThread(0x1752930), current thread is QThread(0x1b27480)
Sep 19 19:48:00 ArkkiVille sddm-greeter[6418]: QObject::installEventFilter(): Cannot filter events for objects in a different thread.
Sep 19 19:48:00 ArkkiVille sddm-greeter[6418]: No Fill10 element found in your theme's battery.svg - Using legacy 20% steps for battery icon
Sep 19 19:48:00 ArkkiVille sddm-greeter[6418]: Adding view for "HDMI-0" QRect(0,0 -2147483648x-2147483648)
Sep 19 19:48:00 ArkkiVille sddm-greeter[6418]: QXcbConnection: XCB error: 2 (BadValue), sequence: 597, resource id: 0, major code: 1 (CreateWindow), minor code: 0
Sep 19 19:48:00 ArkkiVille sddm-greeter[6418]: QXcbConnection: XCB error: 3 (BadWindow), sequence: 598, resource id: 2097162, major code: 2 (ChangeWindowAttributes), minor code: 0
Sep 19 19:48:00 ArkkiVille sddm-greeter[6418]: QXcbConnection: XCB error: 3 (BadWindow), sequence: 599, resource id: 2097162, major code: 18 (ChangeProperty), minor code: 0
Sep 19 19:48:00 ArkkiVille sddm-greeter[6418]: QXcbConnection: XCB error: 3 (BadWindow), sequence: 600, resource id: 2097162, major code: 18 (ChangeProperty), minor code: 0
Sep 19 19:48:00 ArkkiVille sddm-greeter[6418]: QXcbConnection: XCB error: 3 (BadWindow), sequence: 601, resource id: 2097162, major code: 18 (ChangeProperty), minor code: 0
Sep 19 19:48:00 ArkkiVille sddm-greeter[6418]: QXcbConnection: XCB error: 3 (BadWindow), sequence: 603, resource id: 2097162, major code: 18 (ChangeProperty), minor code: 0
Sep 19 19:48:00 ArkkiVille sddm-greeter[6418]: QXcbConnection: XCB error: 3 (BadWindow), sequence: 604, resource id: 2097162, major code: 18 (ChangeProperty), minor code: 0
Sep 19 19:48:00 ArkkiVille sddm-greeter[6418]: QXcbConnection: XCB error: 3 (BadWindow), sequence: 605, resource id: 2097162, major code: 18 (ChangeProperty), minor code: 0
Sep 19 19:48:00 ArkkiVille sddm-greeter[6418]: QXcbConnection: XCB error: 3 (BadWindow), sequence: 608, resource id: 2097162, major code: 18 (ChangeProperty), minor code: 0
Sep 19 19:48:00 ArkkiVille sddm-greeter[6418]: QXcbConnection: XCB error: 3 (BadWindow), sequence: 612, resource id: 2097162, major code: 2 (ChangeWindowAttributes), minor code: 0
Sep 19 19:48:00 ArkkiVille sddm-greeter[6418]: QXcbConnection: XCB error: 3 (BadWindow), sequence: 613, resource id: 2097162, major code: 18 (ChangeProperty), minor code: 0
Sep 19 19:48:00 ArkkiVille sddm-greeter[6418]: QXcbConnection: XCB error: 3 (BadWindow), sequence: 616, resource id: 2097162, major code: 18 (ChangeProperty), minor code: 0
Sep 19 19:48:00 ArkkiVille sddm-greeter[6418]: QXcbConnection: XCB error: 3 (BadWindow), sequence: 617, resource id: 2097162, major code: 20 (GetProperty), minor code: 0
Sep 19 19:48:00 ArkkiVille sddm-greeter[6418]: QXcbConnection: XCB error: 3 (BadWindow), sequence: 621, resource id: 2097162, major code: 18 (ChangeProperty), minor code: 0
Sep 19 19:48:00 ArkkiVille sddm-greeter[6418]: QXcbConnection: XCB error: 3 (BadWindow), sequence: 622, resource id: 2097162, major code: 19 (DeleteProperty), minor code: 0
Sep 19 19:48:00 ArkkiVille sddm-greeter[6418]: QXcbConnection: XCB error: 3 (BadWindow), sequence: 623, resource id: 2097162, major code: 20 (GetProperty), minor code: 0
Sep 19 19:48:00 ArkkiVille sddm-greeter[6418]: QXcbConnection: XCB error: 3 (BadWindow), sequence: 624, resource id: 2097162, major code: 18 (ChangeProperty), minor code: 0
Sep 19 19:48:00 ArkkiVille sddm-greeter[6418]: QXcbConnection: XCB error: 3 (BadWindow), sequence: 625, resource id: 2097162, major code: 18 (ChangeProperty), minor code: 0
Sep 19 19:48:00 ArkkiVille sddm-greeter[6418]: QXcbConnection: XCB error: 3 (BadWindow), sequence: 626, resource id: 2097162, major code: 20 (GetProperty), minor code: 0
Sep 19 19:48:00 ArkkiVille sddm-greeter[6418]: QXcbConnection: XCB error: 3 (BadWindow), sequence: 627, resource id: 2097162, major code: 18 (ChangeProperty), minor code: 0
Sep 19 19:48:00 ArkkiVille sddm-greeter[6418]: QXcbConnection: XCB error: 3 (BadWindow), sequence: 628, resource id: 2097162, major code: 20 (GetProperty), minor code: 0
Sep 19 19:48:00 ArkkiVille sddm-greeter[6418]: QXcbConnection: XCB error: 3 (BadWindow), sequence: 629, resource id: 2097162, major code: 19 (DeleteProperty), minor code: 0
Sep 19 19:48:00 ArkkiVille sddm-greeter[6418]: QXcbConnection: XCB error: 3 (BadWindow), sequence: 630, resource id: 2097162, major code: 8 (MapWindow), minor code: 0
Sep 19 19:48:00 ArkkiVille sddm-greeter[6418]: Message received from daemon: Capabilities
Sep 19 19:48:00 ArkkiVille sddm-greeter[6418]: Message received from daemon: HostName
Sep 19 19:49:16 ArkkiVille sudo[6458]:    ville : TTY=tty2 ; PWD=/home/ville ; USER=root ; COMMAND=/usr/bin/systemctl stop sddm.service
Sep 19 19:49:16 ArkkiVille sudo[6458]: pam_unix(sudo:session): session opened for user root by ville(uid=0)
Sep 19 19:49:16 ArkkiVille systemd[1]: Stopping Simple Desktop Display Manager...
Sep 19 19:49:16 ArkkiVille sddm[6404]: Signal received: SIGTERM
Sep 19 19:49:16 ArkkiVille sddm-greeter[6418]: The X11 connection broke (error 1). Did the X11 server die?
Sep 19 19:49:16 ArkkiVille sddm[6404]: Greeter stopping...
Sep 19 19:49:16 ArkkiVille sddm[6404]: Socket server stopping...
Sep 19 19:49:16 ArkkiVille sddm[6404]: Socket server stopped.
Sep 19 19:49:16 ArkkiVille sddm[6404]: Display server stopping...
Sep 19 19:49:16 ArkkiVille sddm[6404]: Display server stopped.
Sep 19 19:49:16 ArkkiVille sddm[6404]: Running display stop script  "/usr/share/sddm/scripts/Xstop"
Sep 19 19:49:16 ArkkiVille sddm[6404]: Greeter stopping...
Sep 19 19:49:16 ArkkiVille sddm[6404]: QProcess: Destroyed while process ("/usr/lib/sddm/sddm-helper") is still running.
Sep 19 19:49:16 ArkkiVille kernel: sddm-greeter[6418]: segfault at 7f361bb960f0 ip 00007f361bb960f0 sp 00007ffe83dc4768 error 14 in locale-archive[7f361c061000+2ca000]
Sep 19 19:49:16 ArkkiVille systemd[1]: Stopped Simple Desktop Display Manager.
Sep 19 19:49:16 ArkkiVille sudo[6458]: pam_unix(sudo:session): session closed for user root
Sep 19 19:49:16 ArkkiVille systemd[1]: Started Process Core Dump (PID 6462/UID 0).
Sep 19 19:49:16 ArkkiVille kernel: nvidia-modeset: Freed GPU:0 (GPU-f13b272c-a66f-d544-f3f9-ede1ba0a0e9d) @ PCI:0000:01:00.0
Sep 19 19:49:16 ArkkiVille systemd-logind[494]: Removed session c8.
Sep 19 19:49:16 ArkkiVille systemd[1]: Stopping User Manager for UID 617...
Sep 19 19:49:16 ArkkiVille systemd[6413]: Stopped target Default.
Sep 19 19:49:16 ArkkiVille systemd[6413]: Stopping D-Bus User Message Bus...
Sep 19 19:49:16 ArkkiVille systemd[6413]: Stopped D-Bus User Message Bus.
Sep 19 19:49:16 ArkkiVille systemd[6413]: Stopped target Basic System.
Sep 19 19:49:16 ArkkiVille systemd[6413]: Stopped target Sockets.
Sep 19 19:49:16 ArkkiVille systemd[6413]: Closed Sound System.
Sep 19 19:49:16 ArkkiVille systemd[6413]: Stopped target Paths.
Sep 19 19:49:16 ArkkiVille systemd[6413]: Stopped target Timers.
Sep 19 19:49:16 ArkkiVille systemd[6413]: Closed D-Bus User Message Bus Socket.
Sep 19 19:49:16 ArkkiVille systemd[6413]: Reached target Shutdown.
Sep 19 19:49:16 ArkkiVille systemd[6413]: Starting Exit the Session...
Sep 19 19:49:16 ArkkiVille systemd[6413]: Received SIGRTMIN+24 from PID 6468 (kill).
Sep 19 19:49:16 ArkkiVille systemd[6414]: pam_unix(systemd-user:session): session closed for user sddm
Sep 19 19:49:16 ArkkiVille systemd[1]: Stopped User Manager for UID 617.
Sep 19 19:49:16 ArkkiVille systemd[1]: Removed slice User Slice of sddm.
Sep 19 19:49:16 ArkkiVille systemd-coredump[6464]: Process 6418 (sddm-greeter) of user 617 dumped core.
                                                   
                                                   Stack trace of thread 6418:
                                                   #0  0x00007f361bb960f0 n/a (n/a)

Also, it seems it crashes on exit? What do these QXcbConnection BadWindow errors mean?

I forgot to say, that this is on sddm-git (from AUR) but also happens on sddm-0.14.0-2.

EDIT: Also, those who are observant, may notice from the log I've changed theme in sddm.conf from my first post ... I've tried all three currently installed.

Last edited by Wild Penguin (2016-09-19 17:07:29)

fredbezies · 2016-09-22 21:36:43

Could be related to wayland update ?

I saw "SessionCommand=/usr/share/sddm/scripts/wayland-session"

Wayland 1.12.0 was released on september 21st, 2016.

Wild Penguin · 2016-09-29 14:14:36

fredbezies: I though about this, too - more specifically, it occured to me that perhaps sddm uses wayland (for the login screen itself) - but my plasma session currently does not. And if wayland is broken for me, then it would explain why the former does not work but the latter does (because it switches to X.org). But, my HW and driver is quite common one (NVidia proprietary driver, with which GTX 970 or GTX660 both produce the same results), so it is surprising no one has reported the same issue here. After all, sddm is the recommended and default login manager currently for Plasma5.

However, I can find no documentation explaining how to choose wether sddm uses wayland or X.org. I believe the [wayland] section in sddm.conf is parsed only when a user starts a wayland session - not before log in.

Last edited by Wild Penguin (2016-09-29 14:15:45)

arojas · 2016-09-29 14:29:47

sddm doesn't use Wayland

fredbezies · 2016-09-30 12:57:40

Wild Penguin wrote:

fredbezies: I though about this, too - more specifically, it occured to me that perhaps sddm uses wayland (for the login screen itself) - but my plasma session currently does not. And if wayland is broken for me, then it would explain why the former does not work but the latter does (because it switches to X.org). But, my HW and driver is quite common one (NVidia proprietary driver, with which GTX 970 or GTX660 both produce the same results), so it is surprising no one has reported the same issue here. After all, sddm is the recommended and default login manager currently for Plasma5.
However, I can find no documentation explaining how to choose wether sddm uses wayland or X.org. I believe the [wayland] section in sddm.conf is parsed only when a user starts a wayland session - not before log in.

It was just a guess. I'm not using nvidia closed drivers. I had not tested wayland either.

arojas wrote:

sddm doesn't use Wayland

Oops.

My bad!

Arch Linux

#1 2016-09-19 16:44:54

sddm produces black screen, "Cannot create children", autologin works

#2 2016-09-19 16:58:57

Re: sddm produces black screen, "Cannot create children", autologin works

#3 2016-09-22 21:36:43

Re: sddm produces black screen, "Cannot create children", autologin works

#4 2016-09-29 14:14:36

Re: sddm produces black screen, "Cannot create children", autologin works

#5 2016-09-29 14:29:47

Re: sddm produces black screen, "Cannot create children", autologin works

#6 2016-09-30 12:57:40

Re: sddm produces black screen, "Cannot create children", autologin works

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