[PATCH v5 4/5] drm: Connector helper function to release resources

[Maarten Lankhorst]

Op 30-03-17 om 10:42 schreef Dhinakaran Pandiyan:
> From: "Pandiyan, Dhinakaran" <dhinakaran.pandiyan at intel.com>
>
> Having an ->atomic_release callback is useful to release shared resources
> that get allocated in compute_config(). This function is expected to be
> called in the atomic_check() phase before new resources are acquired.
>
> v4: Document that the function is conditionally called and before
> other atomic_checks() (Daniel)
> v3: Use the new 'for_each_oldnew_connector_in_state()' macro.
> v2: Moved the caller hunk to this patch (Daniel)
>
> Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
> Cc: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
> Cc: Archit Taneja <architt at codeaurora.org>
> Cc: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Harry Wentland <Harry.wentland at amd.com>
> Reviewed-by: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
> Reviewed-by: Daniel Vetter <daniel.vetter at ffwll.ch>
> Suggested-by: Daniel Vetter <daniel.vetter at ffwll.ch>
> Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandiyan at intel.com>
> ---
>  drivers/gpu/drm/drm_atomic_helper.c      | 19 +++++++++++++++++++
>  include/drm/drm_modeset_helper_vtables.h | 16 ++++++++++++++++
>  2 files changed, 35 insertions(+)
>
> diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
> index d14094d..9d07669 100644
> --- a/drivers/gpu/drm/drm_atomic_helper.c
> +++ b/drivers/gpu/drm/drm_atomic_helper.c
> @@ -586,6 +586,25 @@ drm_atomic_helper_check_modeset(struct drm_device *dev,
>  		}
>  	}
>  
> +	for_each_oldnew_connector_in_state(state, connector, old_connector_state, new_connector_state, i) {
> +		const struct drm_connector_helper_funcs *conn_funcs;
> +		struct drm_crtc_state *crtc_state;
> +
> +		conn_funcs = connector->helper_private;
> +		if (!conn_funcs->atomic_release)
> +			continue;
> +
> +		if (!old_connector_state->crtc)
> +			continue;
> +
> +		crtc_state = drm_atomic_get_existing_crtc_state(state, old_connector_state->crtc);
> +
> +		if (crtc_state->connectors_changed ||
> +		    crtc_state->mode_changed ||
> +		    (crtc_state->active_changed && !crtc_state->active))
> +			conn_funcs->atomic_release(connector, new_connector_state);
> +	}
> +
>  	return mode_fixup(state);
>  }
Oops, I'm just looking at patch 5 again..

atomic_release should return an int to allow error propogation. There's no good reason why it shouldn't.
This would allow handling errors in patch 5 more gracefully.
>  EXPORT_SYMBOL(drm_atomic_helper_check_modeset);
> diff --git a/include/drm/drm_modeset_helper_vtables.h b/include/drm/drm_modeset_helper_vtables.h
> index 091c422..84e80aa 100644
> --- a/include/drm/drm_modeset_helper_vtables.h
> +++ b/include/drm/drm_modeset_helper_vtables.h
> @@ -836,6 +836,22 @@ struct drm_connector_helper_funcs {
>  	 */
>  	struct drm_encoder *(*atomic_best_encoder)(struct drm_connector *connector,
>  						   struct drm_connector_state *connector_state);
> +
> +	/**
> +	 * @atomic_release:
> +	 *
> +	 * This function is conditionally called to release shared resources
> +	 * when the attached CRTC's mode changes or it's connectors change or
> +	 * becomes inactive. It is called before the corresponding
> +	 * &drm_crtc_helper_funcs.atomic_check or
> +	 * &drm_crtc_helper_funcs.mode_fixup hooks are called.
> +	 *
> +	 * NOTE:
> +	 *
> +	 * This function is called in the check phase of an atomic update.
> +	 */
> +	void (*atomic_release)(struct drm_connector *connector,
> +			       struct drm_connector_state *connector_state);
>  };
>  
>  /**