[PATCH 8/8] drm/i915/backlight: Avoid 0 brightness for INTEL AUX HDR backlight by default

[Suraj Kandpal <suraj.kandpal@intel.com>]

Whenever the minimum brightness is reported as 0 there are chances
we maybe sometimes end up with blank screen. This confuses the user
into thinking the display is acting weird. This occurs in eDP 1.4b
when we use proprietary INTEL AUX HDR DPCD registers to manipulate
brightness via luminance values. Make sure if minimum luminance
range is 0 we program the default luminance value to max, if
brightness level is reported as 0.

Signed-off-by: Suraj Kandpal <suraj.kandpal@intel.com>
---
v1 -> v2:
- Let users set brightness to 0, make it so that it's just not
done by default (Arun)

 drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c b/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
index aac6cdb5b69b..725370bcfa3b 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
@@ -442,6 +442,8 @@ intel_dp_aux_hdr_setup_backlight(struct intel_connector *connector, enum pipe pi
 
 	panel->backlight.level = intel_dp_aux_hdr_get_backlight(connector, pipe);
 	panel->backlight.enabled = panel->backlight.level != 0;
+	if (!panel->backlight.level)
+		panel->backlight.level = panel->backlight.max;
 
 	return 0;
 }
-- 
2.34.1