Comment 1 for bug 850065

There's a known issue with toshiba_acpi loading on newer models, but that module shouldn't be necessary to control your backlight (and on some models the interface used by toshiba_acpi doesn't allow adjusting the backlight anyway). Backlight control should still be possible via the generic ACPI backlight device. Are you unable to adjust the brightness level at all?

Can you please run 'ubuntu-bug -p linux 850065' in a terminal to attach relevant logs to this bug report? Please also install the fwts package (sudo apt-get install fwts), then run 'sudo fwts --disassemble-aml' and attach the *.dsl files it generates to this bug as well. Thanks!