drm/amd/display: Add a backlight module option

There seem devices that don't work with the aux channel backlight
control.  For allowing such users to test with the other backlight
control method, provide a new module option, aux_backlight, to specify
enabling or disabling the aux backport support explicitly.  As
default, the aux support is detected by the hardware capability.

v2: make the backlight option generic in case we add future
backlight types (Alex)

BugLink: https://bugzilla.opensuse.org/show_bug.cgi?id=1180749
BugLink: https://gitlab.freedesktop.org/drm/amd/-/issues/1438
Reviewed-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
This commit is contained in:
Takashi Iwai
2021-02-03 13:42:41 +01:00
committed by Alex Deucher
parent f275e8759c
commit 7c20984795
3 changed files with 10 additions and 0 deletions

View File

@@ -2324,6 +2324,11 @@ static void update_connector_ext_caps(struct amdgpu_dm_connector *aconnector)
caps->ext_caps->bits.hdr_aux_backlight_control == 1)
caps->aux_support = true;
if (amdgpu_backlight == 0)
caps->aux_support = false;
else if (amdgpu_backlight == 1)
caps->aux_support = true;
/* From the specification (CTA-861-G), for calculating the maximum
* luminance we need to use:
* Luminance = 50*2**(CV/32)