drm/atomic-helper: Make atomic_enable/disable crtc callbacks optional

Allow atomic_enable and atomic_disable operations from
drm_crtc_helper_funcs struct optional. With this, the target display
drivers don't need to define a dummy function if they don't need one.

Changes since v2:
* Don't make funcs optional
* Update kerneldoc for atomic_enable/disable
* Replace "if (funcs->atomic_enable)" by "if (funcs->commit)"
* Improve commit message

Signed-off-by: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20190314184845.gjmvkamobj4dilyp@smtp.gmail.com
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
index 40ac198..fbb7633 100644 (file)
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -1034,7 +1034,7 @@ disable_outputs(struct drm_device *dev, struct drm_atomic_state *old_state)
                        funcs->atomic_disable(crtc, old_crtc_state);
                else if (funcs->disable)
                        funcs->disable(crtc);
-               else
+               else if (funcs->dpms)
                        funcs->dpms(crtc, DRM_MODE_DPMS_OFF);
 
                if (!(dev->irq_enabled && dev->num_crtcs))
@@ -1277,10 +1277,9 @@ void drm_atomic_helper_commit_modeset_enables(struct drm_device *dev,
                if (new_crtc_state->enable) {
                        DRM_DEBUG_ATOMIC("enabling [CRTC:%d:%s]\n",
                                         crtc->base.id, crtc->name);
-
                        if (funcs->atomic_enable)
                                funcs->atomic_enable(crtc, old_crtc_state);
-                       else
+                       else if (funcs->commit)
                                funcs->commit(crtc);
                }
        }

diff --git a/include/drm/drm_modeset_helper_vtables.h b/include/drm/drm_modeset_helper_vtables.h
index cfb7be4..ce4de6b 100644 (file)
--- a/include/drm/drm_modeset_helper_vtables.h
+++ b/include/drm/drm_modeset_helper_vtables.h
@@ -418,6 +418,8 @@ struct drm_crtc_helper_funcs {
         * Drivers can use the @old_crtc_state input parameter if the operations
         * needed to enable the CRTC don't depend solely on the new state but
         * also on the transition between the old state and the new state.
+        *
+        * This function is optional.
         */
        void (*atomic_enable)(struct drm_crtc *crtc,
                              struct drm_crtc_state *old_crtc_state);
@@ -441,6 +443,8 @@ struct drm_crtc_helper_funcs {
         * parameter @old_crtc_state which could be used to access the old
         * state. Atomic drivers should consider to use this one instead
         * of @disable.
+        *
+        * This function is optional.
         */
        void (*atomic_disable)(struct drm_crtc *crtc,
                               struct drm_crtc_state *old_crtc_state);