* @state: atomic state
*
* Free all the memory allocated by drm_atomic_state_init.
- * This is useful for drivers that subclass the atomic state.
+ * This should only be used by drivers which are still subclassing
+ * &drm_atomic_state and haven't switched to &drm_private_state yet.
*/
void drm_atomic_state_default_release(struct drm_atomic_state *state)
{
* @state: atomic state
*
* Default implementation for filling in a new atomic state.
- * This is useful for drivers that subclass the atomic state.
+ * This should only be used by drivers which are still subclassing
+ * &drm_atomic_state and haven't switched to &drm_private_state yet.
*/
int
drm_atomic_state_init(struct drm_device *dev, struct drm_atomic_state *state)
* @state: atomic state
*
* Default implementation for clearing atomic state.
- * This is useful for drivers that subclass the atomic state.
+ * This should only be used by drivers which are still subclassing
+ * &drm_atomic_state and haven't switched to &drm_private_state yet.
*/
void drm_atomic_state_default_clear(struct drm_atomic_state *state)
{
}
/**
+ * DOC: handling driver private state
+ *
+ * Very often the DRM objects exposed to userspace in the atomic modeset api
+ * (&drm_connector, &drm_crtc and &drm_plane) do not map neatly to the
+ * underlying hardware. Especially for any kind of shared resources (e.g. shared
+ * clocks, scaler units, bandwidth and fifo limits shared among a group of
+ * planes or CRTCs, and so on) it makes sense to model these as independent
+ * objects. Drivers then need to do similar state tracking and commit ordering for
+ * such private (since not exposed to userpace) objects as the atomic core and
+ * helpers already provide for connectors, planes and CRTCs.
+ *
+ * To make this easier on drivers the atomic core provides some support to track
+ * driver private state objects using struct &drm_private_obj, with the
+ * associated state struct &drm_private_state.
+ *
+ * Similar to userspace-exposed objects, private state structures can be
+ * acquired by calling drm_atomic_get_private_obj_state(). Since this function
+ * does not take care of locking, drivers should wrap it for each type of
+ * private state object they have with the required call to drm_modeset_lock()
+ * for the corresponding &drm_modeset_lock.
+ *
+ * All private state structures contained in a &drm_atomic_state update can be
+ * iterated using for_each_oldnew_private_obj_in_state(),
+ * for_each_new_private_obj_in_state() and for_each_old_private_obj_in_state().
+ * Drivers are recommended to wrap these for each type of driver private state
+ * object they have, filtering on &drm_private_obj.funcs using for_each_if(), at
+ * least if they want to iterate over all objects of a given type.
+ *
+ * An earlier way to handle driver private state was by subclassing struct
+ * &drm_atomic_state. But since that encourages non-standard ways to implement
+ * the check/commit split atomic requires (by using e.g. "check and rollback or
+ * commit instead" of "duplicate state, check, then either commit or release
+ * duplicated state) it is deprecated in favour of using &drm_private_state.
+ */
+
+/**
* drm_atomic_private_obj_init - initialize private object
* @obj: private object
* @state: initial private object state
struct drm_private_state *state);
};
+/**
+ * struct drm_private_obj - base struct for driver private atomic object
+ *
+ * A driver private object is initialized by calling
+ * drm_atomic_private_obj_init() and cleaned up by calling
+ * drm_atomic_private_obj_fini().
+ *
+ * Currently only tracks the state update functions and the opaque driver
+ * private state itself, but in the future might also track which
+ * &drm_modeset_lock is required to duplicate and update this object's state.
+ */
struct drm_private_obj {
+ /**
+ * @state: Current atomic state for this driver private object.
+ */
struct drm_private_state *state;
+ /**
+ * @funcs:
+ *
+ * Functions to manipulate the state of this driver private object, see
+ * &drm_private_state_funcs.
+ */
const struct drm_private_state_funcs *funcs;
};
+/**
+ * struct drm_private_state - base struct for driver private object state
+ * @state: backpointer to global drm_atomic_state
+ *
+ * Currently only contains a backpointer to the overall atomic update, but in
+ * the future also might hold synchronization information similar to e.g.
+ * &drm_crtc.commit.
+ */
struct drm_private_state {
struct drm_atomic_state *state;
};
* state easily. If this hook is implemented, drivers must also
* implement @atomic_state_clear and @atomic_state_free.
*
+ * Subclassing of &drm_atomic_state is deprecated in favour of using
+ * &drm_private_state and &drm_private_obj.
+ *
* RETURNS:
*
* A new &drm_atomic_state on success or NULL on failure.
*
* Drivers that implement this must call drm_atomic_state_default_clear()
* to clear common state.
+ *
+ * Subclassing of &drm_atomic_state is deprecated in favour of using
+ * &drm_private_state and &drm_private_obj.
*/
void (*atomic_state_clear)(struct drm_atomic_state *state);
*
* Drivers that implement this must call
* drm_atomic_state_default_release() to release common resources.
+ *
+ * Subclassing of &drm_atomic_state is deprecated in favour of using
+ * &drm_private_state and &drm_private_obj.
*/
void (*atomic_state_free)(struct drm_atomic_state *state);
};
projects / platform / kernel / linux-rpi3.git / commitdiff