Ok, the solution is the following, as crazy at it may sound. I have to plug in and turn on the external display while the laptop is showing the bios options. If I plug it later, or before switching it on, it won't be detected!
-- External display through display port not working https://bugs.launchpad.net/bugs/636903 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
