Join Log in
Score:0
avatar Ubuntu

Multiple monitors : Black screen with blinking cursor and GNOME Desktop login only shows after switching console

ke flag
jmsjr
  • Ubuntu 20.04.3 LTS HWE
  • Dell Laptop with integrated Intel GPU and Discrete nVidia GPU
  • Dual monitor ( Laptop monitor + Desktop monitor via HDMI from laptop )
  • Configured display to "Join Display" between the two monitors

Ever since this : Ubuntu 20.04.3 LTS with HWE stack - No GUI / GNOME Desktop Manager wont start after running "Software Updater" on Dell Laptop

... when I reboot, I see:

  • GRUB menu
  • Then the Dell logo ( either after pressing Enter or waiting for it to just start Ubuntu )
  • Then the screen output flickers ( off then on ) 2 or 3 times
  • Then a blank screen with a blinking cursor at the top left of the screen

At this point, I thought that the boot failed to start Ubuntu, but if I switch to console 2 ( Ctrl-Alt-F2 ) then back to console 1 ( Ctrl-Alt-F1 ), then the GNOME login screen is started ... as in it it looks like the login screen only starts after I switch back back to console 1 ( That is, just the purple background colour first and then the login GUI after about 1 to 2 seconds ).

Furthermore, I see the following logs in /var/log/apport.log, which corresponds to about the time I do the reboots:

ERROR: apport (pid 1349) Sat Jan 29 10:58:04 2022: called for pid 987, signal 6, core limit 0, dump mode 2
ERROR: apport (pid 1349) Sat Jan 29 10:58:04 2022: not creating core for pid with dump mode of 2
ERROR: apport (pid 1349) Sat Jan 29 10:58:04 2022: executable: /usr/lib/xorg/Xorg (command line "/usr/lib/xorg/Xorg vt1 -displayfd 3 -auth /run/user/125/gdm/Xauthority -background none -noreset -keeptty -verbose 3")
ERROR: apport (pid 1349) Sat Jan 29 10:58:04 2022: is_closing_session(): no DBUS_SESSION_BUS_ADDRESS in environment
ERROR: apport (pid 1349) Sat Jan 29 10:58:05 2022: wrote report /var/crash/_usr_lib_xorg_Xorg.0.crash

ERROR: apport (pid 1348) Sat Jan 29 11:04:23 2022: called for pid 978, signal 6, core limit 0, dump mode 2
ERROR: apport (pid 1348) Sat Jan 29 11:04:23 2022: not creating core for pid with dump mode of 2
ERROR: apport (pid 1348) Sat Jan 29 11:04:23 2022: executable: /usr/lib/xorg/Xorg (command line "/usr/lib/xorg/Xorg vt1 -displayfd 3 -auth /run/user/125/gdm/Xauthority -background none -noreset -keeptty -verbose 3")
ERROR: apport (pid 1348) Sat Jan 29 11:04:23 2022: is_closing_session(): no DBUS_SESSION_BUS_ADDRESS in environment
ERROR: apport (pid 1348) Sat Jan 29 11:04:23 2022: this executable already crashed 2 times, ignoring

ERROR: apport (pid 1388) Sat Jan 29 11:06:34 2022: called for pid 1043, signal 6, core limit 0, dump mode 2
ERROR: apport (pid 1388) Sat Jan 29 11:06:34 2022: not creating core for pid with dump mode of 2
ERROR: apport (pid 1388) Sat Jan 29 11:06:34 2022: executable: /usr/lib/xorg/Xorg (command line "/usr/lib/xorg/Xorg vt1 -displayfd 3 -auth /run/user/125/gdm/Xauthority -background none -noreset -keeptty -verbose 3")
ERROR: apport (pid 1388) Sat Jan 29 11:06:34 2022: is_closing_session(): no DBUS_SESSION_BUS_ADDRESS in environment
ERROR: apport (pid 1388) Sat Jan 29 11:06:34 2022: this executable already crashed 2 times, ignoring

ERROR: apport (pid 1369) Sat Jan 29 11:22:08 2022: called for pid 1022, signal 6, core limit 0, dump mode 2
ERROR: apport (pid 1369) Sat Jan 29 11:22:08 2022: not creating core for pid with dump mode of 2
ERROR: apport (pid 1369) Sat Jan 29 11:22:08 2022: executable: /usr/lib/xorg/Xorg (command line "/usr/lib/xorg/Xorg vt1 -displayfd 3 -auth /run/user/125/gdm/Xauthority -background none -noreset -keeptty -verbose 3")
ERROR: apport (pid 1369) Sat Jan 29 11:22:08 2022: is_closing_session(): no DBUS_SESSION_BUS_ADDRESS in environment
ERROR: apport (pid 1369) Sat Jan 29 11:22:08 2022: this executable already crashed 2 times, ignoring
131
0 + 0
Score:0
avatar Ubuntu
ke flag
jmsjr

I figured out what combination gives this behaviour, but not sure why that is happening.

Basically, it has to do with what is the Primary Display, as shown here :

enter image description here

The above screenshot shows that :

  • Display (1) is my laptop dispay
  • Display (2) is my desktop monitor display ( connected via HDMI from laptop )
  • Primary Display is the desktop monitor

With the above combination, I get a blank screen with a blinking cursor at the top left as described in the question on reboot and I see the GUI ( actually, I think the GUI only starts as there is a delay ) when I switch console to any other ( say two via Ctrl-Alt-F2 ) then back to console 1 ( Ctrl-Alt-F1 ).

Now if I change the settings so that my Primary Display is my laptop monitor, like the screenshot below :

enter image description here

.. then when I reboot, the Gnome login screen shows correctly ( without me doing Ctrl-Alt-F2 then Ctrl-Alt-F1 ). There is still a bit of flicker in the beginning though.

Also confirmed that in this setup ( Primary Display is laptop monitor ), there are no crash entries in /var/log/apport.log.

I also do not see this behaviour if I close the laptop lid so that I only work on the desktop monitor ... but I now keep the laptop lid open as I get lower bandwidth with my wifi with the laptop lid closed.

( 95+ Mbps with laptop lid open vs ~15 Mbps with laptop lid closed ).

0 + 0
ke flag
jmsjr
Added a comment at https://bugs.launchpad.net/ubuntu/+source/xorg-server/+bug/1811023 with link to this page. User PJSingh5000 in that bug report used the exact same trick with Ctrl-Alt-F2 then Ctrl-Alt-F1 that I did.
0
Reply
ธงชาติไทย
Elon Musk
I sit in a Tesla and translated this thread with Ai:

mangohost

Post an answer

Most people don’t grasp that asking a lot of questions unlocks learning and improves interpersonal bonding. In Alison’s studies, for example, though people could accurately recall how many questions had been asked in their conversations, they didn’t intuit the link between questions and liking. Across four studies, in which participants were engaged in conversations themselves or read transcripts of others’ conversations, people tended not to realize that question asking would influence—or had influenced—the level of amity between the conversationalists.