[PATCH 3/3] drm/connector: hdmi: Use YUV420 output format as an RGB fallback

[Cristian Ciocaltea]

Introduce the switch to YUV420 when computing the best output format and
RGB cannot be supported for a given color depth.

While at it, add a minor improvement to the debug message indicating the
supported format.

Signed-off-by: Cristian Ciocaltea <cristian.ciocal...@collabora.com>
---
 drivers/gpu/drm/display/drm_hdmi_state_helper.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/display/drm_hdmi_state_helper.c 
b/drivers/gpu/drm/display/drm_hdmi_state_helper.c
index 
3a55881a544a519bb1254968db891c814f831a0f..b4e865e0680f35fd2d849536789f6c1f98a48258
 100644
--- a/drivers/gpu/drm/display/drm_hdmi_state_helper.c
+++ b/drivers/gpu/drm/display/drm_hdmi_state_helper.c
@@ -304,7 +304,7 @@ hdmi_try_format_bpc(const struct drm_connector *connector,
                return false;
        }
 
-       drm_dbg_kms(dev, "%s output format supported with %u (TMDS char rate: 
%llu Hz)\n",
+       drm_dbg_kms(dev, "%s output format supported with %u bpc (TMDS char 
rate: %llu Hz)\n",
                    drm_hdmi_connector_get_output_format_name(fmt),
                    bpc, conn_state->hdmi.tmds_char_rate);
 
@@ -319,15 +319,16 @@ hdmi_compute_format(const struct drm_connector *connector,
 {
        struct drm_device *dev = connector->dev;
 
-       /*
-        * TODO: Add support for YCbCr420 output for HDMI 2.0 capable
-        * devices, for modes that only support YCbCr420.
-        */
        if (hdmi_try_format_bpc(connector, conn_state, mode, bpc, 
HDMI_COLORSPACE_RGB)) {
                conn_state->hdmi.output_format = HDMI_COLORSPACE_RGB;
                return 0;
        }
 
+       if (hdmi_try_format_bpc(connector, conn_state, mode, bpc, 
HDMI_COLORSPACE_YUV420)) {
+               conn_state->hdmi.output_format = HDMI_COLORSPACE_YUV420;
+               return 0;
+       }
+
        drm_dbg_kms(dev, "Failed. No Format Supported for that bpc count.\n");
 
        return -EINVAL;

-- 
2.47.0