[Intel-gfx] [PATCH] drm: Warn if plane/crtc/encoder/connector index exceeds our 32bit bitmasks

[Ville Syrjala]

From: Ville Syrjälä <ville.syrjala at linux.intel.com>

We use 32bit bitmasks to track planes/crtcs/encoders/connectors.
Naturally we can only do that if the index of those objects stays
below 32. Issue a warning whenever we exceed that limit, hopefully
prompting someone to fix the problem.

Or should we just outright fail the object initializatio perhaps?

Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
---
 drivers/gpu/drm/drm_connector.c | 3 +++
 drivers/gpu/drm/drm_crtc.c      | 3 +++
 drivers/gpu/drm/drm_encoder.c   | 3 +++
 drivers/gpu/drm/drm_plane.c     | 3 +++
 4 files changed, 12 insertions(+)

diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c
index b85a7749709d..9278a81c5d54 100644
--- a/drivers/gpu/drm/drm_connector.c
+++ b/drivers/gpu/drm/drm_connector.c
@@ -211,6 +211,9 @@ int drm_connector_init(struct drm_device *dev,
 	connector->index = ret;
 	ret = 0;
 
+	/* we have 32bit connector bitmasks */
+	WARN_ON(connector->index >= 32);
+
 	connector->connector_type = connector_type;
 	connector->connector_type_id =
 		ida_simple_get(connector_ida, 1, 0, GFP_KERNEL);
diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index f0556e654116..e27ffa3561af 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -318,6 +318,9 @@ int drm_crtc_init_with_planes(struct drm_device *dev, struct drm_crtc *crtc,
 	list_add_tail(&crtc->head, &config->crtc_list);
 	crtc->index = config->num_crtc++;
 
+	/* we have 32bit crtc bitmasks */
+	WARN_ON(crtc->index >= 32);
+
 	crtc->primary = primary;
 	crtc->cursor = cursor;
 	if (primary && !primary->possible_crtcs)
diff --git a/drivers/gpu/drm/drm_encoder.c b/drivers/gpu/drm/drm_encoder.c
index 59e0ebe733f8..66d0cdd217fa 100644
--- a/drivers/gpu/drm/drm_encoder.c
+++ b/drivers/gpu/drm/drm_encoder.c
@@ -136,6 +136,9 @@ int drm_encoder_init(struct drm_device *dev,
 	list_add_tail(&encoder->head, &dev->mode_config.encoder_list);
 	encoder->index = dev->mode_config.num_encoder++;
 
+	/* we have 32bit encoder bitmasks */
+	WARN_ON(encoder->index >= 32);
+
 out_put:
 	if (ret)
 		drm_mode_object_unregister(dev, &encoder->base);
diff --git a/drivers/gpu/drm/drm_plane.c b/drivers/gpu/drm/drm_plane.c
index 2c90519576a3..0a8d807603c1 100644
--- a/drivers/gpu/drm/drm_plane.c
+++ b/drivers/gpu/drm/drm_plane.c
@@ -242,6 +242,9 @@ int drm_universal_plane_init(struct drm_device *dev, struct drm_plane *plane,
 	list_add_tail(&plane->head, &config->plane_list);
 	plane->index = config->num_total_plane++;
 
+	/* we have 32bit plane bitmasks */
+	WARN_ON(plane->index >= 32);
+
 	drm_object_attach_property(&plane->base,
 				   config->plane_type_property,
 				   plane->type);
-- 
2.13.6