See commit 751109aad5834375ca9ed0dcfcd85a00cbf872b5. Setting video.use_native_backlight=0 is a workaround because it makes /sys/class/backlight/acpi_video0/brightness come back.
See commit 751109aad583437 5ca9ed0dcfcd85a 00cbf872b5. Setting video.use_ native_ backlight= 0 is a workaround because it makes /sys/class/ backlight/ acpi_video0/ brightness come back.