I wanted my external screen to work in it's correct resolution while being on the console (without Xorg).
Here's what I've done to get it work:
- On boot select Hardware info and look for your desired resolution code e.g. 895
- Edit /boot/syslinux/syslinux.cfg
- Add
vga=895
to the APPEND line in your appropriate block
Old value: APPEND root=/dev/sda1 rw
New value: APPEND root=/dev/sda1 rw vga=895
In case you'd like to rotate the screen counterclockwise (pivot):
$ echo 3 | sudo tee /sys/class/graphics/fbcon/rotate