[PATCH v2 14/14] drm: Validate encoder->possible_crtcs

[Ville Syrjala <ville.syrjala@xxxxxxxxxxxxxxx>]

From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>

WARN if the encoder possible_crtcs is effectively empty or contains
bits for non-existing crtcs.

TODO: Or should we perhapst just filter out any bit for a
non-exisiting crtc?

Signed-off-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
---
 drivers/gpu/drm/drm_encoder.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/drivers/gpu/drm/drm_encoder.c b/drivers/gpu/drm/drm_encoder.c
index 3ece97a9d029..07191e2db64c 100644
--- a/drivers/gpu/drm/drm_encoder.c
+++ b/drivers/gpu/drm/drm_encoder.c
@@ -106,6 +106,23 @@ static void validate_possible_clones(struct drm_encoder *encoder)
 	     encoder->possible_clones, encoder_mask);
 }
 
+static void validate_possible_crtcs(struct drm_encoder *encoder)
+{
+	struct drm_device *dev = encoder->dev;
+	struct drm_crtc *crtc;
+	u32 crtc_mask = 0;
+
+	drm_for_each_crtc(crtc, dev)
+		crtc_mask |= drm_crtc_mask(crtc);
+
+	WARN((encoder->possible_crtcs & crtc_mask) == 0 ||
+	     (encoder->possible_crtcs & ~crtc_mask) != 0,
+	     "Bogus possible_crtcs: "
+	     "[ENCODER:%d:%s] possible_crtcs=0x%x (full crtc mask=0x%x)\n",
+	     encoder->base.id, encoder->name,
+	     encoder->possible_crtcs, crtc_mask);
+}
+
 int drm_encoder_register_all(struct drm_device *dev)
 {
 	struct drm_encoder *encoder;
@@ -114,6 +131,7 @@ int drm_encoder_register_all(struct drm_device *dev)
 	fixup_possible_clones(dev);
 
 	drm_for_each_encoder(encoder, dev) {
+		validate_possible_crtcs(encoder);
 		validate_possible_clones(encoder);
 
 		if (encoder->funcs->late_register)
-- 
2.21.0

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