[Intel-gfx] [PATCH] drm/i915: Only enable DFP 4:4:4->4:2:0 conversion when outputting YCbCr 4:4:4

[Ville Syrjala]

From: Ville Syrjälä <ville.syrjala at linux.intel.com>

Let's not enable the 4:4:4->4:2:0 conversion bit in the DFP unless we're
actually outputting YCbCr 4:4:4. It would appear some protocol
converters blindy consult this bit even when the source is outputting
RGB, resulting in a visual mess.

Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/2914
Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
---
 drivers/gpu/drm/i915/display/intel_dp.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index 4f190a82d4ad..aa30ef9f6906 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -4368,8 +4368,8 @@ void intel_dp_configure_protocol_converter(struct intel_dp *intel_dp,
 		drm_dbg_kms(&i915->drm, "Failed to set protocol converter HDMI mode to %s\n",
 			    enableddisabled(intel_dp->has_hdmi_sink));
 
-	tmp = intel_dp->dfp.ycbcr_444_to_420 ?
-		DP_CONVERSION_TO_YCBCR420_ENABLE : 0;
+	tmp = crtc_state->output_format == INTEL_OUTPUT_FORMAT_YCBCR444 &&
+		intel_dp->dfp.ycbcr_444_to_420 ? DP_CONVERSION_TO_YCBCR420_ENABLE : 0;
 
 	if (drm_dp_dpcd_writeb(&intel_dp->aux,
 			       DP_PROTOCOL_CONVERTER_CONTROL_1, tmp) != 1)
-- 
2.26.2