Comment 69 for bug 1752053

I have an Asus ROG GL703VD and have a similar issue. The display shows the ROG display, then flashes purple for a second (Grub menu splash before the Ubuntu splash logo, which doesn't display on the laptop, but does on the HDMI display) then goes blank and never comes online. Even pressing CTRL+ALT+F1-6 does not switch between virtual terminals on the laptop display, it does shift on the mirrored HDMI display. The only way to get a display is to hook up a monitor to the HDMI port and then logging in and setting the display to mirror mode. In fact, this is the only way to install Bionic on the device as even booting the install media with nouveau blacklisted doesn't work. In previous releases, running nouveau.modeset=0 would bring up the display properly and then you could install, but with Bionic, this is does not work. Also, installing the Bionic kernel in Xenial or Artful creates the same condition for those releases.
I have looked at the logs and settings everywhere, and from what I can tell everything appears to be loading properly. Gnome sees both displays when connected, but the laptop display remains black.