The new DRM color format property allows userspace to request a specific
color format on a connector. In turn, this fills the connector state's
color_format member to switch color formats.

Make drm_bridges consider the color_format set in the connector state
during the atomic bridge check. Specifically, reject any output bus
formats that do not correspond to the requested color format.

Signed-off-by: Nicolas Frattaroli <nicolas.frattaroli@collabora.com>
---
 drivers/gpu/drm/drm_bridge.c | 45 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 45 insertions(+)

diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c
index 8f355df883d8..8aac9747f35e 100644
--- a/drivers/gpu/drm/drm_bridge.c
+++ b/drivers/gpu/drm/drm_bridge.c
@@ -1052,6 +1052,47 @@ static int select_bus_fmt_recursive(struct drm_bridge *first_bridge,
 	return ret;
 }
 
+static bool __pure bus_format_is_color_fmt(u32 bus_fmt, enum drm_color_format fmt)
+{
+	if (fmt == DRM_COLOR_FORMAT_AUTO)
+		return true;
+
+	switch (bus_fmt) {
+	case MEDIA_BUS_FMT_FIXED:
+		return true;
+	case MEDIA_BUS_FMT_RGB888_1X24:
+	case MEDIA_BUS_FMT_RGB101010_1X30:
+	case MEDIA_BUS_FMT_RGB121212_1X36:
+	case MEDIA_BUS_FMT_RGB161616_1X48:
+		return fmt == DRM_COLOR_FORMAT_RGB444;
+	case MEDIA_BUS_FMT_YUV8_1X24:
+	case MEDIA_BUS_FMT_YUV10_1X30:
+	case MEDIA_BUS_FMT_YUV12_1X36:
+	case MEDIA_BUS_FMT_YUV16_1X48:
+		return fmt == DRM_COLOR_FORMAT_YCBCR444;
+	case MEDIA_BUS_FMT_UYVY8_1X16:
+	case MEDIA_BUS_FMT_VYUY8_1X16:
+	case MEDIA_BUS_FMT_YUYV8_1X16:
+	case MEDIA_BUS_FMT_YVYU8_1X16:
+	case MEDIA_BUS_FMT_UYVY10_1X20:
+	case MEDIA_BUS_FMT_YUYV10_1X20:
+	case MEDIA_BUS_FMT_VYUY10_1X20:
+	case MEDIA_BUS_FMT_YVYU10_1X20:
+	case MEDIA_BUS_FMT_UYVY12_1X24:
+	case MEDIA_BUS_FMT_VYUY12_1X24:
+	case MEDIA_BUS_FMT_YUYV12_1X24:
+	case MEDIA_BUS_FMT_YVYU12_1X24:
+		return fmt == DRM_COLOR_FORMAT_YCBCR422;
+	case MEDIA_BUS_FMT_UYYVYY8_0_5X24:
+	case MEDIA_BUS_FMT_UYYVYY10_0_5X30:
+	case MEDIA_BUS_FMT_UYYVYY12_0_5X36:
+	case MEDIA_BUS_FMT_UYYVYY16_0_5X48:
+		return fmt == DRM_COLOR_FORMAT_YCBCR420;
+	default:
+		return false;
+	}
+}
+
 /*
  * This function is called by &drm_atomic_bridge_chain_check() just before
  * calling &drm_bridge_funcs.atomic_check() on all elements of the chain.
@@ -1137,6 +1178,10 @@ drm_atomic_bridge_chain_select_bus_fmts(struct drm_bridge *bridge,
 	}
 
 	for (i = 0; i < num_out_bus_fmts; i++) {
+		if (!bus_format_is_color_fmt(out_bus_fmts[i], conn_state->color_format)) {
+			ret = -ENOTSUPP;
+			continue;
+		}
 		ret = select_bus_fmt_recursive(bridge, last_bridge, crtc_state,
 					       conn_state, out_bus_fmts[i]);
 		if (ret != -ENOTSUPP)

-- 
2.52.0