Comment 30 for bug 1894667

This is kind of expected since it is common that systems from 2011 use ACPI video interface. You can add the kernel into /etc/default/grub to make it consist across boots.

I will compile a linux kernel with a workaround of "acpi_backlight=video" for testing. If this work I can submit to linux kernel and you will not need to add kernel parameters in the future.