From: Ville Syrjälä <ville.syrjala@linux.intel.com>
Date: Thu, 9 Apr 2026 10:15:33 +0000 (+0300)
Subject: drm/i915/hdmi: Restructure 4:2:0 vs. 4:4:4 mode validation
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a68d3d7fd9766141f2e7cf21c2644d74f24ae888;p=thirdparty%2Fkernel%2Flinux.git

drm/i915/hdmi: Restructure 4:2:0 vs. 4:4:4 mode validation

Restructure the HDMI mode validation to resemble the new
intel_hdmi_compute_formats(). Keeping the two in sync helps
to avoid different bugs in each.

The main difference between mode_valid() and
intel_hdmi_compute_formats() is that we don't want the
Hail Mary RGB fallback for "4:2:0 only" modes.

Cc: Nicolas Frattaroli <nicolas.frattaroli@collabora.com>
Reviewed-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patch.msgid.link/20260409101539.22032-4-ville.syrjala@linux.intel.com
Tested-by: Nicolas Frattaroli <nicolas.frattaroli@collabora.com>
---

diff --git a/drivers/gpu/drm/i915/display/intel_hdmi.c b/drivers/gpu/drm/i915/display/intel_hdmi.c
index 9c241d93166c8..79093d8fc2e61 100644
--- a/drivers/gpu/drm/i915/display/intel_hdmi.c
+++ b/drivers/gpu/drm/i915/display/intel_hdmi.c
@@ -2045,6 +2045,27 @@ intel_hdmi_sink_format_valid(struct intel_connector *connector,
 	}
 }
 
+static enum drm_mode_status
+intel_hdmi_mode_valid_format(struct intel_connector *connector,
+			     const struct drm_display_mode *mode,
+			     int clock, bool has_hdmi_sink,
+			     enum intel_output_format sink_format)
+{
+	struct intel_display *display = to_intel_display(connector);
+	enum drm_mode_status status;
+
+	status = intel_hdmi_sink_format_valid(connector, mode,
+					      has_hdmi_sink, sink_format);
+	if (status != MODE_OK)
+		return status;
+
+	status = intel_pfit_mode_valid(display, mode, sink_format, 0);
+	if (status != MODE_OK)
+		return status;
+
+	return intel_hdmi_mode_clock_valid(&connector->base, clock, has_hdmi_sink, sink_format);
+}
+
 static enum drm_mode_status
 intel_hdmi_mode_valid(struct drm_connector *_connector,
 		      const struct drm_display_mode *mode)
@@ -2052,12 +2073,11 @@ intel_hdmi_mode_valid(struct drm_connector *_connector,
 	struct intel_connector *connector = to_intel_connector(_connector);
 	struct intel_display *display = to_intel_display(connector);
 	struct intel_hdmi *hdmi = intel_attached_hdmi(connector);
+	const struct drm_display_info *info = &connector->base.display_info;
 	enum drm_mode_status status;
 	int clock = mode->clock;
 	int max_dotclk = display->cdclk.max_dotclk_freq;
 	bool has_hdmi_sink = intel_has_hdmi_sink(hdmi, connector->base.state);
-	bool ycbcr_420_only;
-	enum intel_output_format sink_format;
 
 	status = intel_cpu_transcoder_mode_valid(display, mode);
 	if (status != MODE_OK)
@@ -2084,36 +2104,20 @@ intel_hdmi_mode_valid(struct drm_connector *_connector,
 	if (clock > 600000)
 		return MODE_CLOCK_HIGH;
 
-	ycbcr_420_only = drm_mode_is_420_only(&connector->base.display_info, mode);
-
-	if (ycbcr_420_only)
-		sink_format = INTEL_OUTPUT_FORMAT_YCBCR420;
-	else
-		sink_format = INTEL_OUTPUT_FORMAT_RGB;
+	if (drm_mode_is_420_only(info, mode)) {
+		status = intel_hdmi_mode_valid_format(connector, mode, clock, has_hdmi_sink,
+						      INTEL_OUTPUT_FORMAT_YCBCR420);
+	} else {
+		status = intel_hdmi_mode_valid_format(connector, mode, clock, has_hdmi_sink,
+						      INTEL_OUTPUT_FORMAT_RGB);
 
-	status = intel_pfit_mode_valid(display, mode, sink_format, 0);
+		if (status != MODE_OK && drm_mode_is_420_also(info, mode))
+			status = intel_hdmi_mode_valid_format(connector, mode, clock, has_hdmi_sink,
+							      INTEL_OUTPUT_FORMAT_YCBCR420);
+	}
 	if (status != MODE_OK)
 		return status;
 
-	status = intel_hdmi_mode_clock_valid(&connector->base, clock, has_hdmi_sink, sink_format);
-	if (status != MODE_OK) {
-		if (ycbcr_420_only ||
-		    !connector->base.ycbcr_420_allowed ||
-		    !drm_mode_is_420_also(&connector->base.display_info, mode))
-			return status;
-
-		sink_format = INTEL_OUTPUT_FORMAT_YCBCR420;
-
-		status = intel_pfit_mode_valid(display, mode, sink_format, 0);
-		if (status != MODE_OK)
-			return status;
-
-		status = intel_hdmi_mode_clock_valid(&connector->base, clock, has_hdmi_sink,
-						     sink_format);
-		if (status != MODE_OK)
-			return status;
-	}
-
 	return intel_mode_valid_max_plane_size(display, mode, 1);
 }