I have a Toshiba Tecra M5 with Nvidia graphics. If I boot it up without an external display connected then the internal display will work fine but it will not connect to an external display, but if I boot it up with an external display already connected then the external display will work but the internal display will be stuck on its lowest backlight brightness setting. If I try to edit the config file "/proc/acpi/toshiba/video" then I will get the error "Hit unhandled case 13 (Error writing to file: Invalid argument) in parse_error." What do I do?