[PATCH RFC 5/5] drm/meson: Output in YUV444 if sink supports it

[Neil Armstrong]

With the YUV420 handling, we can dynamically setup the HDMI output
pixel format depending on the mode and connector info.
So now, we can output in YUV444, which is the native video pipeline
format, directly to the HDMI Sink if it's supported without
necessarily involving the HDMI Controller CSC.

Signed-off-by: Neil Armstrong <narmstrong@xxxxxxxxxxxx>
---
 drivers/gpu/drm/meson/meson_dw_hdmi.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/meson/meson_dw_hdmi.c b/drivers/gpu/drm/meson/meson_dw_hdmi.c
index 5d67e2beba58..8bf9db7f39a4 100644
--- a/drivers/gpu/drm/meson/meson_dw_hdmi.c
+++ b/drivers/gpu/drm/meson/meson_dw_hdmi.c
@@ -723,12 +723,23 @@ static int meson_venc_hdmi_encoder_atomic_check(struct drm_encoder *encoder,
 	struct drm_display_mode *mode = &crtc_state->mode;
 	bool is_hdmi2_sink =
 		conn_state->connector->display_info.hdmi.scdc.supported;
+	bool specify_out_format = false;
+	u32 out_format;
 
 	if (drm_mode_is_420_only(info, mode) ||
 	    (!is_hdmi2_sink && drm_mode_is_420_also(info, mode)))
 		dw_hdmi->input_bus_format = MEDIA_BUS_FMT_UYYVYY8_0_5X24;
-	else
+	else {
 		dw_hdmi->input_bus_format = MEDIA_BUS_FMT_YUV8_1X24;
+		if (info->color_formats & DRM_COLOR_FORMAT_YCRCB444) {
+			out_format = MEDIA_BUS_FMT_YUV8_1X24;
+			specify_out_format = true;
+		}
+	}
+
+	/* Set a connector bus format is required */
+	drm_display_info_set_bus_formats(info, &out_format,
+					 (specify_out_format ? 1 : 0));
 
 	/* Specify the encoder output format to the bridge */
 	if (!drm_bridge_format_set(encoder->bridge,
-- 
2.21.0