I performed system update some time ago (2 or 3 weeks) and left my computer unused. Today I tried to power on it and I was very surprised, because I didn't see anything on screen during boot and after it. I rebooted computer in fallback mode (I also added "i915.modeset=0" to kernel init args), and I saw command line. Then I updated whole system and rebooted it again - no luck again blank screen during boot and after.
I rebooted it one more time, but with default kernel (I disabled KMS again via GRUB command line) and I saw systemd output during boot. I teems, that all services were started successfully, because all messages were prefixed with "OK". Then I cloud only use command line, because Gnome 3 was not running under seventh console.
Any idea what is going one here?