With the introduction of the "color format" DRM property, which allows
userspace to request a specific color format, the HDMI state helper
should implement this.

Implement it by checking whether the property is set and set to
something other than auto. If so, pass the requested color format, and
otherwise set RGB.

Signed-off-by: Nicolas Frattaroli <nicolas.frattaroli@collabora.com>
---
 drivers/gpu/drm/display/drm_hdmi_state_helper.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/display/drm_hdmi_state_helper.c b/drivers/gpu/drm/display/drm_hdmi_state_helper.c
index a561f124be99..5da956bdd68c 100644
--- a/drivers/gpu/drm/display/drm_hdmi_state_helper.c
+++ b/drivers/gpu/drm/display/drm_hdmi_state_helper.c
@@ -649,11 +649,21 @@ hdmi_compute_config(const struct drm_connector *connector,
 	unsigned int max_bpc = clamp_t(unsigned int,
 				       conn_state->max_bpc,
 				       8, connector->max_bpc);
+	enum hdmi_colorspace hdmi_colorspace =
+		drm_color_format_to_hdmi_colorspace(conn_state->color_format);
 	int ret;
 
 	ret = hdmi_compute_format_bpc(connector, conn_state, mode, max_bpc,
-				      HDMI_COLORSPACE_RGB);
+				      hdmi_colorspace);
 	if (ret) {
+		/* If a color format was explicitly requested, don't fall back */
+		if (conn_state->color_format) {
+			drm_dbg_kms(connector->dev,
+				    "Explicitly set color format '%s' doesn't work.\n",
+				    drm_get_color_format_name(conn_state->color_format));
+			return ret;
+		}
+
 		if (connector->ycbcr_420_allowed) {
 			ret = hdmi_compute_format_bpc(connector, conn_state,
 						      mode, max_bpc,

-- 
2.52.0