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Commit 2a8d3eac authored by Ville Syrjälä's avatar Ville Syrjälä
Browse files

drm: Warn if plane/crtc/encoder/connector index exceeds our 32bit bitmasks 



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.

For connectors the issue is a bit more complicated as they can
be created/destroyed at runtime due to MST. So the problem is no
longer a purely theoretical programmer error. As the connector
indexes are allocated via ida, we can simply limit the maximum
value the ida is allowed to hand out. The error handling is already
in place.

v2: Return an error to the caller (Harry)
v3: Print a debug message so that we know what happened (Maarten)

Cc: Harry Wentland <harry.wentland@amd.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: default avatarMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: default avatarVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180125133020.23845-1-ville.syrjala@linux.intel.com


Reviewed-by: default avatarHarry Wentland <harry.wentland@amd.com>
parent 65f7fa3a

drivers/gpu/drm/drm_connector.c

+7 −2
Original line number Diff line number Diff line
@@ -205,9 +205,14 @@ int drm_connector_init(struct drm_device *dev, 
	connector->dev = dev;

	connector->funcs = funcs;



	ret = ida_simple_get(&config->connector_ida, 0, 0, GFP_KERNEL);

	if (ret < 0)

	/* connector index is used with 32bit bitmasks */

	ret = ida_simple_get(&config->connector_ida, 0, 32, GFP_KERNEL);

	if (ret < 0) {

		DRM_DEBUG_KMS("Failed to allocate %s connector index: %d\n",

			      drm_connector_enum_list[connector_type].name,

			      ret);

		goto out_put;

	}

	connector->index = ret;

	ret = 0;

drivers/gpu/drm/drm_crtc.c

+4 −0
Original line number Diff line number Diff line
@@ -282,6 +282,10 @@ int drm_crtc_init_with_planes(struct drm_device *dev, struct drm_crtc *crtc, 
	WARN_ON(primary && primary->type != DRM_PLANE_TYPE_PRIMARY);

	WARN_ON(cursor && cursor->type != DRM_PLANE_TYPE_CURSOR);



	/* crtc index is used with 32bit bitmasks */

	if (WARN_ON(config->num_crtc >= 32))

		return -EINVAL;



	crtc->dev = dev;

	crtc->funcs = funcs;

drivers/gpu/drm/drm_encoder.c

+4 −0
Original line number Diff line number Diff line
@@ -110,6 +110,10 @@ int drm_encoder_init(struct drm_device *dev, 
{

	int ret;



	/* encoder index is used with 32bit bitmasks */

	if (WARN_ON(dev->mode_config.num_encoder >= 32))

		return -EINVAL;



	ret = drm_mode_object_add(dev, &encoder->base, DRM_MODE_OBJECT_ENCODER);

	if (ret)

		return ret;

drivers/gpu/drm/drm_plane.c

+4 −0
Original line number Diff line number Diff line
@@ -173,6 +173,10 @@ int drm_universal_plane_init(struct drm_device *dev, struct drm_plane *plane, 
	unsigned int format_modifier_count = 0;

	int ret;



	/* plane index is used with 32bit bitmasks */

	if (WARN_ON(config->num_total_plane >= 32))

		return -EINVAL;



	ret = drm_mode_object_add(dev, &plane->base, DRM_MODE_OBJECT_PLANE);

	if (ret)

		return ret;