Commits
Aaron Lu committed a50188dae30
acpi: video: enhance the quirk detect logic of _BQC Currently we decide if the _BQC is using index by first setting the level to maximum, and then check if _BQC returned maximum; if not, we say it is using index. This is not true for some buggy systems, where the _BQC method will always return a constant value(e.g. 0 or 100 for the two broken system) and thus break the current logic. So this patch tries to enhance the quirk detect logic for _BQC: we do this by picking a test_level, it can be the maximum level or the mininum one based on some condition. And we don't make the assumption that if _BQC returned a value that is not what we just set, it must be using an index. Instead, we will compare the value returned from _BQC and if it doesn't match, see if the returned value is an index. And if still no, clear the capability of _BQC. References: https://bugzilla.kernel.org/show_bug.cgi?id=42861 References: https://bugzilla.kernel.org/show_bug.cgi?id=56011 Reported-and-tested-by: Artem Savkov <artem.savkov@gmail.com> Reported-by: Luis Medinas <lmedinas@gmail.com> Reported-by: Cheppes <cheppes@mailinator.com> Signed-off-by: Aaron Lu <aaron.lu@intel.com> Acked-by: Zhang Rui <rui.zhang@intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>