From: Cristian Ciocaltea <cristian.ciocaltea@collabora.com>
Date: Tue, 27 May 2025 12:11:10 +0000 (+0300)
Subject: drm/connector: hdmi: Add support for YUV420 format verification
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=85b0db87417eb66c41fd7c74979312fde9383315;p=thirdparty%2Fkernel%2Flinux.git

drm/connector: hdmi: Add support for YUV420 format verification

Provide the necessary constraints verification in
sink_supports_format_bpc() in order to support handling of YUV420
output format.

Reviewed-by: Maxime Ripard <mripard@kernel.org>
Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@collabora.com>
Link: https://lore.kernel.org/r/20250527-hdmi-conn-yuv-v5-2-74c9c4a8ac0c@collabora.com
Signed-off-by: Maxime Ripard <mripard@kernel.org>
---

diff --git a/drivers/gpu/drm/display/drm_hdmi_state_helper.c b/drivers/gpu/drm/display/drm_hdmi_state_helper.c
index 97cb4f29c4b5d..e026f1ca82848 100644
--- a/drivers/gpu/drm/display/drm_hdmi_state_helper.c
+++ b/drivers/gpu/drm/display/drm_hdmi_state_helper.c
@@ -3,6 +3,7 @@
 #include <drm/drm_atomic.h>
 #include <drm/drm_connector.h>
 #include <drm/drm_edid.h>
+#include <drm/drm_modes.h>
 #include <drm/drm_print.h>
 
 #include <drm/display/drm_hdmi_audio_helper.h>
@@ -408,6 +409,11 @@ sink_supports_format_bpc(const struct drm_connector *connector,
 		return false;
 	}
 
+	if (drm_mode_is_420_only(info, mode) && format != HDMI_COLORSPACE_YUV420) {
+		drm_dbg_kms(dev, "Mode can be only supported in YUV420 format.\n");
+		return false;
+	}
+
 	switch (format) {
 	case HDMI_COLORSPACE_RGB:
 		drm_dbg_kms(dev, "RGB Format, checking the constraints.\n");
@@ -438,9 +444,36 @@ sink_supports_format_bpc(const struct drm_connector *connector,
 		return true;
 
 	case HDMI_COLORSPACE_YUV420:
-		/* TODO: YUV420 is unsupported at the moment. */
-		drm_dbg_kms(dev, "YUV420 format isn't supported yet.\n");
-		return false;
+		drm_dbg_kms(dev, "YUV420 format, checking the constraints.\n");
+
+		if (!(info->color_formats & DRM_COLOR_FORMAT_YCBCR420)) {
+			drm_dbg_kms(dev, "Sink doesn't support YUV420.\n");
+			return false;
+		}
+
+		if (!drm_mode_is_420(info, mode)) {
+			drm_dbg_kms(dev, "Mode cannot be supported in YUV420 format.\n");
+			return false;
+		}
+
+		if (bpc == 10 && !(info->hdmi.y420_dc_modes & DRM_EDID_YCBCR420_DC_30)) {
+			drm_dbg_kms(dev, "10 BPC but sink doesn't support Deep Color 30.\n");
+			return false;
+		}
+
+		if (bpc == 12 && !(info->hdmi.y420_dc_modes & DRM_EDID_YCBCR420_DC_36)) {
+			drm_dbg_kms(dev, "12 BPC but sink doesn't support Deep Color 36.\n");
+			return false;
+		}
+
+		if (bpc == 16 && !(info->hdmi.y420_dc_modes & DRM_EDID_YCBCR420_DC_48)) {
+			drm_dbg_kms(dev, "16 BPC but sink doesn't support Deep Color 48.\n");
+			return false;
+		}
+
+		drm_dbg_kms(dev, "YUV420 format supported in that configuration.\n");
+
+		return true;
 
 	case HDMI_COLORSPACE_YUV422:
 		drm_dbg_kms(dev, "YUV422 format, checking the constraints.\n");