Mainline kernel doesn't fix this issue - tested with the same boot flags, only acpi_osi= is bringing backlight control back. Tested with 4.3.0-040300-generic #201511020949
Mainline kernel doesn't fix this issue - tested with the same boot flags, only acpi_osi= is bringing backlight control back. generic #201511020949
Tested with 4.3.0-040300-