Check that all encoders attached to a given CRTC are valid
possible_clones of each other.

Signed-off-by: Jessica Zhang <quic_jesszhan@quicinc.com>
---

NOTE: Appropriate KUnit tests for this change will be posted in a
separate series
---
 drivers/gpu/drm/drm_atomic_helper.c | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
index 43cdf39019a44537794cc5a519d139b0cb77073c..cc4001804fdc6155e4200ce5830cdc74be201351 100644
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -574,6 +574,25 @@ mode_valid(struct drm_atomic_state *state)
 	return 0;
 }
 
+static int drm_atomic_check_valid_clones(struct drm_atomic_state *state,
+					 struct drm_crtc *crtc)
+{
+	struct drm_encoder *drm_enc;
+	struct drm_crtc_state *crtc_state = drm_atomic_get_new_crtc_state(state,
+									  crtc);
+
+	drm_for_each_encoder_mask(drm_enc, crtc->dev, crtc_state->encoder_mask) {
+		if ((crtc_state->encoder_mask & drm_enc->possible_clones) !=
+		    crtc_state->encoder_mask) {
+			DRM_DEBUG("crtc%d failed valid clone check for mask 0x%x\n",
+				  crtc->base.id, crtc_state->encoder_mask);
+			return -EINVAL;
+		}
+	}
+
+	return 0;
+}
+
 /**
  * drm_atomic_helper_check_modeset - validate state object for modeset changes
  * @dev: DRM device
@@ -745,6 +764,10 @@ drm_atomic_helper_check_modeset(struct drm_device *dev,
 		ret = drm_atomic_add_affected_planes(state, crtc);
 		if (ret != 0)
 			return ret;
+
+		ret = drm_atomic_check_valid_clones(state, crtc);
+		if (ret != 0)
+			return ret;
 	}
 
 	/*

-- 
2.34.1