-
Alexander Monakov authored
Documentation for sysfs backlight level interface requires that values in both 'brightness' and 'actual_brightness' files are interpreted to be in range from 0 to the value given in the 'max_brightness' file. With amdgpu, max_brightness gives 255, and values written by the user into 'brightness' are internally rescaled to a wider range. However, reading from 'actual_brightness' gives the raw register value without inverse rescaling. This causes issues for various userspace tools such as PowerTop and systemd that expect the value to be in the correct range. Introduce a helper to retrieve internal backlight range. Use it to reimplement 'convert_brightness' as 'convert_brightness_from_user' and introduce 'convert_brightness_to_user'. Bug: https://bugzilla.kernel.org/show_bug.cgi?id=203905 Bug: https://gitlab.freedesktop.org/drm/amd/-/issues/1242 Cc: Alex Deucher <alexander.deucher@amd.com> Cc: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com> Reviewed-by:
Alex Deucher <alexander.deucher@amd.com> Signed-off-by:
Alexander Monakov <amonakov@ispras.ru> Signed-off-by:
Alex Deucher <alexander.deucher@amd.com> Cc: stable@vger.kernel.org
69d9f427