I have a BPI-M1 with Armbian installed. Recently I performed a apt-update then apt-upgrade on it. The upgrade was successful without major error. However, after the upgrade I found out that the desktop does not show up. Using Alt-Ctrl-Function keys I can get to log in normally but neither startx nor service lightdm start work.
Several things to notice are:
There is an xorg session error log showing a bunch of Failed to load module "xapp-gtk3-module" messages. I followed the answer of 20.04 - Failed to load module “xapp-gtk3-module” - Ask Ubuntu and installed xapp. I then deleted the error logs and it never appeared again. However, this does not fix the issue.
Attempts to do Xorg -configure result in ‘No devices to configure, Configuration failed’ and then ‘(EE) Server terminated with error (2). Closing log file’. I tried to add a ‘60-video-card.conf’ file to both /etc/X11/xorg.conf.d/ and /usr/share/X11/xorg.conf.d/, this has no effect on the issue.
Content of the file I added:
Section "Device"
Identifier "fb0"
Driver "modesetting"
EndSection
(By using dd if=/dev/random of=/dev/fb0 command it can be determined that fb0 is the main HDMI output)
Finally, during boot there is a warning message:
driver "simple-framebuffer" is already registered aborting
Since the issue seem to be xorg not seeing display device, I consider this to be the root cause. However, although several people had the same issue before, none of their questions got answered.