Posting this just in case it appears in google and helps another person struggling with this issue.
There’s a problem with my Sasmsung R700, in that the backlight is at maximum brightness when booting up, and when in the BIOS menu, but at some point during boot it drops down to a near unusable level. The brightness adjustment keys also didn’t work, so I was stuck with a horrible display. The fix is to blacklist the video driver causing the problem:
echo blacklist video | sudo tee -a /etc/modprobe.d/local
Running this then rebooting fixed the problem. Hope this helps someone!
