So this boils down to (newbie guide)
Alt+F2 (opens Run Application dialog box): gksudo gedit /etc/default/grub
now change the line
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
to
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_osi=Linux acpi_backlight=vendor"
save & close
Nice one Mark!
So this boils down to (newbie guide) LINUX_DEFAULT= "quiet splash" LINUX_DEFAULT= "quiet splash acpi_osi=Linux acpi_backlight= vendor"
Alt+F2 (opens Run Application dialog box): gksudo gedit /etc/default/grub
now change the line
GRUB_CMDLINE_
to
GRUB_CMDLINE_
save & close
Alt+F2: gksudo update-grub
Now reboot