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drm: Introduce helper for replacing blob properties
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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@collabora.com>
Cc: Dave Airlie <airlied@redhat.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
[danvet: Squash in fixup from Daniel for the kerneldoc, reported by
0day builder.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
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Daniel Stone authored and Daniel Vetter committed May 8, 2015
1 parent 4339ed8 commit d2ed343
Showing 1 changed file with 106 additions and 49 deletions.
155 changes: 106 additions & 49 deletions drivers/gpu/drm/drm_crtc.c
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Original file line number Diff line number Diff line change
Expand Up @@ -4238,6 +4238,83 @@ static void drm_property_destroy_blob(struct drm_device *dev,
kfree(blob);
}

/**
* 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
* @prop_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
Expand Down Expand Up @@ -4287,7 +4364,7 @@ int drm_mode_getblob_ioctl(struct drm_device *dev,
/**
* 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
Expand All @@ -4301,20 +4378,14 @@ 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);
Expand All @@ -4333,16 +4404,16 @@ 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;
}

Expand All @@ -4351,16 +4422,13 @@ 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);
Expand All @@ -4380,33 +4448,22 @@ 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);
Expand Down

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