drm: Document deprecated load/unload hook

 * structure for GEM drivers.

 */

struct drm_driver {

	/**

	 * @load:

	 *

	 * Backward-compatible driver callback to complete

	 * initialization steps after the driver is registered.  For

	 * this reason, may suffer from race conditions and its use is

	 * deprecated for new drivers.  It is therefore only supported

	 * for existing drivers not yet converted to the new scheme.

	 * See drm_dev_init() and drm_dev_register() for proper and

	 * race-free way to set up a &struct drm_device.

	 *

	 * Returns:

	 *

	 * Zero on success, non-zero value on failure.

	 */

	int (*load) (struct drm_device *, unsigned long flags);

	int (*firstopen) (struct drm_device *);

	int (*open) (struct drm_device *, struct drm_file *);

	void (*preclose) (struct drm_device *, struct drm_file *file_priv);

	void (*postclose) (struct drm_device *, struct drm_file *);

	void (*lastclose) (struct drm_device *);

	/**

	 * @unload:

	 *

	 * Reverse the effects of the driver load callback.  Ideally,

	 * the clean up performed by the driver should happen in the

	 * reverse order of the initialization.  Similarly to the load

	 * hook, this handler is deprecated and its usage should be

	 * dropped in favor of an open-coded teardown function at the

	 * driver layer.  See drm_dev_unregister() and drm_dev_unref()

	 * for the proper way to remove a &struct drm_device.

	 *

	 * The unload() hook is called right after unregistering

	 * the device.

	 *

	 * Returns:

	 *

	 * The return value is ignored.

	 */

	int (*unload) (struct drm_device *);

	int (*dma_ioctl) (struct drm_device *dev, void *data, struct drm_file *file_priv);

	int (*dma_quiescent) (struct drm_device *);