I upgraded from Ubuntu 17.10 to 18.04 and everything was fine for about 2 moths after the upgrade.
Now, my system boots to a black screen (the monitor backlight keeps on), and I can only reach the login screen after about 5 minutes.
Curiously, if I keep pressing the key "E" repeatedly during boot, it boots normally and quickly.
I've removed "quiet splash" from /etc/default/boot and sudp update-grub2, but I don't see any errors among those commands. It quickly goes to a full black screen.
I've tried sudo apt-get install lightdm sudo apt-get install xfce sudo dpkg-reconfigure gdm3 sudo dpkg-reconfigure lightdm
(not in that specific order... those are just the commands i've already tried).
I don't use nvidia video card.
The output from dmesg | less > dmesg.txt
can be downloaded from my google drive, the link below, if the forum allows: https://drive.google.com/open?id=1aj9n4ovguhZ4ewJCbQ_FR9jRJEjd8t18
This is my workstation and I can't format it.
I would appreciate any help.
Thank you! Thiago Garcia.