[PATCH 4/7] drm: Introduce helper for replacing blob properties
Daniel Stone
daniels at collabora.com
Mon Apr 20 11:22:53 PDT 2015
Introduce a common helper for the pattern of:
- allocate new blob property
- potentially free old blob property
- replace content of indicative property with new blob ID
- change member pointer on modeset object
Signed-off-by: Daniel Stone <daniels at collabora.com>
Cc: Dave Airlie <airlied at redhat.com>
---
drivers/gpu/drm/drm_crtc.c | 155 +++++++++++++++++++++++++++++++--------------
1 file changed, 106 insertions(+), 49 deletions(-)
diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index aae0d84..ed9341d 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -4237,6 +4237,83 @@ static void drm_property_destroy_blob(struct drm_device *dev,
}
/**
+ * drm_property_replace_global_blob - atomically replace existing blob property
+ * @dev: drm device
+ * @replace: location of blob property pointer to be replaced
+ * @length: length of data for new blob, or 0 for no data
+ * @data: content for new blob, or NULL for no data
+ * @obj_holds_id: optional object for property holding blob ID
+ * @holds_id: optional property holding blob ID
+ * @return 0 on success or error on failure
+ *
+ * This function will atomically replace a global property in the blob list,
+ * optionally updating a property which holds the ID of that property. It is
+ * guaranteed to be atomic: no caller will be allowed to see intermediate
+ * results, and either the entire operation will succeed and clean up the
+ * previous property, or it will fail and the state will be unchanged.
+ *
+ * If length is 0 or data is NULL, no new blob will be created, and the holding
+ * property, if specified, will be set to 0.
+ *
+ * Access to the replace pointer is assumed to be protected by the caller, e.g.
+ * by holding the relevant modesetting object lock for its parent.
+ *
+ * For example, a drm_connector has a 'PATH' property, which contains the ID
+ * of a blob property with the value of the MST path information. Calling this
+ * function with replace pointing to the connector's path_blob_ptr, length and
+ * data set for the new path information, obj_holds_id set to the connector's
+ * base object, and prop_holds_id set to the path property name, will perform
+ * a completely atomic update. The access to path_blob_ptr is protected by the
+ * caller holding a lock on the connector.
+ */
+static int drm_property_replace_global_blob(struct drm_device *dev,
+ struct drm_property_blob **replace,
+ size_t length,
+ const void *data,
+ struct drm_mode_object *obj_holds_id,
+ struct drm_property *prop_holds_id)
+{
+ struct drm_property_blob *new_blob = NULL;
+ struct drm_property_blob *old_blob = NULL;
+ int ret;
+
+ WARN_ON(replace == NULL);
+
+ old_blob = *replace;
+
+ if (length && data) {
+ new_blob = drm_property_create_blob(dev, length, data);
+ if (!new_blob)
+ return -EINVAL;
+ }
+
+ /* This does not need to be synchronised with blob_lock, as the
+ * get_properties ioctl locks all modesetting objects, and
+ * obj_holds_id must be locked before calling here, so we cannot
+ * have its value out of sync with the list membership modified
+ * below under blob_lock. */
+ if (obj_holds_id) {
+ ret = drm_object_property_set_value(obj_holds_id,
+ prop_holds_id,
+ new_blob ?
+ new_blob->base.id : 0);
+ if (ret != 0)
+ goto err_created;
+ }
+
+ if (old_blob)
+ drm_property_destroy_blob(dev, old_blob);
+
+ *replace = new_blob;
+
+ return 0;
+
+err_created:
+ drm_property_destroy_blob(dev, new_blob);
+ return ret;
+}
+
+/**
* drm_mode_getblob_ioctl - get the contents of a blob property value
* @dev: DRM device
* @data: ioctl data
@@ -4285,7 +4362,7 @@ done:
/**
* drm_mode_connector_set_path_property - set tile property on connector
* @connector: connector to set property on.
- * @path: path to use for property.
+ * @path: path to use for property; must not be NULL.
*
* This creates a property to expose to userspace to specify a
* connector path. This is mainly used for DisplayPort MST where
@@ -4299,20 +4376,14 @@ int drm_mode_connector_set_path_property(struct drm_connector *connector,
const char *path)
{
struct drm_device *dev = connector->dev;
- size_t size = strlen(path) + 1;
int ret;
- if (connector->path_blob_ptr)
- drm_property_destroy_blob(dev, connector->path_blob_ptr);
-
- connector->path_blob_ptr = drm_property_create_blob(connector->dev,
- size, path);
- if (!connector->path_blob_ptr)
- return -EINVAL;
-
- ret = drm_object_property_set_value(&connector->base,
- dev->mode_config.path_property,
- connector->path_blob_ptr->base.id);
+ ret = drm_property_replace_global_blob(dev,
+ &connector->path_blob_ptr,
+ strlen(path) + 1,
+ path,
+ &connector->base,
+ dev->mode_config.path_property);
return ret;
}
EXPORT_SYMBOL(drm_mode_connector_set_path_property);
@@ -4331,16 +4402,16 @@ EXPORT_SYMBOL(drm_mode_connector_set_path_property);
int drm_mode_connector_set_tile_property(struct drm_connector *connector)
{
struct drm_device *dev = connector->dev;
- int ret, size;
char tile[256];
-
- if (connector->tile_blob_ptr)
- drm_property_destroy_blob(dev, connector->tile_blob_ptr);
+ int ret;
if (!connector->has_tile) {
- connector->tile_blob_ptr = NULL;
- ret = drm_object_property_set_value(&connector->base,
- dev->mode_config.tile_property, 0);
+ ret = drm_property_replace_global_blob(dev,
+ &connector->tile_blob_ptr,
+ 0,
+ NULL,
+ &connector->base,
+ dev->mode_config.tile_property);
return ret;
}
@@ -4349,16 +4420,13 @@ int drm_mode_connector_set_tile_property(struct drm_connector *connector)
connector->num_h_tile, connector->num_v_tile,
connector->tile_h_loc, connector->tile_v_loc,
connector->tile_h_size, connector->tile_v_size);
- size = strlen(tile) + 1;
- connector->tile_blob_ptr = drm_property_create_blob(connector->dev,
- size, tile);
- if (!connector->tile_blob_ptr)
- return -EINVAL;
-
- ret = drm_object_property_set_value(&connector->base,
- dev->mode_config.tile_property,
- connector->tile_blob_ptr->base.id);
+ ret = drm_property_replace_global_blob(dev,
+ &connector->tile_blob_ptr,
+ strlen(tile) + 1,
+ tile,
+ &connector->base,
+ dev->mode_config.tile_property);
return ret;
}
EXPORT_SYMBOL(drm_mode_connector_set_tile_property);
@@ -4378,33 +4446,22 @@ int drm_mode_connector_update_edid_property(struct drm_connector *connector,
const struct edid *edid)
{
struct drm_device *dev = connector->dev;
- size_t size;
+ size_t size = 0;
int ret;
/* ignore requests to set edid when overridden */
if (connector->override_edid)
return 0;
- if (connector->edid_blob_ptr)
- drm_property_destroy_blob(dev, connector->edid_blob_ptr);
-
- /* Delete edid, when there is none. */
- if (!edid) {
- connector->edid_blob_ptr = NULL;
- ret = drm_object_property_set_value(&connector->base, dev->mode_config.edid_property, 0);
- return ret;
- }
-
- size = EDID_LENGTH * (1 + edid->extensions);
- connector->edid_blob_ptr = drm_property_create_blob(connector->dev,
- size, edid);
- if (!connector->edid_blob_ptr)
- return -EINVAL;
-
- ret = drm_object_property_set_value(&connector->base,
- dev->mode_config.edid_property,
- connector->edid_blob_ptr->base.id);
+ if (edid)
+ size = EDID_LENGTH + (1 + edid->extensions);
+ ret = drm_property_replace_global_blob(dev,
+ &connector->edid_blob_ptr,
+ size,
+ edid,
+ &connector->base,
+ dev->mode_config.edid_property);
return ret;
}
EXPORT_SYMBOL(drm_mode_connector_update_edid_property);
--
2.3.5
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