drm/atomic: add commit_planes_on_crtc helper

drm_atomic_helper_commit_planes calls all atomic_begin's first,
then updates all planes, finally calling atomic_flush.

Some drivers may want to things like disabling irq's
from their atomic_begin, in which case a second call to atomic_begin
will splat. By using commit_planes_on_crtc on each crtc in the
atomic state they'll evade that issue.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
[danvet: Extend kerneldoc a bit as discussed with Maarten on irc.]
[danvet: Squash in fixup to check for crtc_funcs in all places.
Reported by Dan Carpenter.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
index b82ef626246913afe824392703a6b4cbceacffba..424a98bfa6869a283090dc641948452ea485c3d9 100644 (file)
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -1127,6 +1127,10 @@ EXPORT_SYMBOL(drm_atomic_helper_prepare_planes);
  *
  * It still requires the global state object @old_state to know which planes and
  * crtcs need to be updated though.
+ *
+ * Note that this function does all plane updates across all CRTCs in one step.
+ * If the hardware can't support this approach look at
+ * drm_atomic_helper_commit_planes_on_crtc() instead.
  */
 void drm_atomic_helper_commit_planes(struct drm_device *dev,
                                     struct drm_atomic_state *old_state)
@@ -1180,6 +1184,64 @@ void drm_atomic_helper_commit_planes(struct drm_device *dev,
 }
 EXPORT_SYMBOL(drm_atomic_helper_commit_planes);
 
+/**
+ * drm_atomic_helper_commit_planes_on_crtc - commit plane state for a crtc
+ * @old_crtc_state: atomic state object with the old crtc state
+ *
+ * This function commits the new plane state using the plane and atomic helper
+ * functions for planes on the specific crtc. It assumes that the atomic state
+ * has already been pushed into the relevant object state pointers, since this
+ * step can no longer fail.
+ *
+ * This function is useful when plane updates should be done crtc-by-crtc
+ * instead of one global step like drm_atomic_helper_commit_planes() does.
+ *
+ * This function can only be savely used when planes are not allowed to move
+ * between different CRTCs because this function doesn't handle inter-CRTC
+ * depencies. Callers need to ensure that either no such depencies exist,
+ * resolve them through ordering of commit calls or through some other means.
+ */
+void
+drm_atomic_helper_commit_planes_on_crtc(struct drm_crtc_state *old_crtc_state)
+{
+       const struct drm_crtc_helper_funcs *crtc_funcs;
+       struct drm_crtc *crtc = old_crtc_state->crtc;
+       struct drm_atomic_state *old_state = old_crtc_state->state;
+       struct drm_plane *plane;
+       unsigned plane_mask;
+
+       plane_mask = old_crtc_state->plane_mask;
+       plane_mask |= crtc->state->plane_mask;
+
+       crtc_funcs = crtc->helper_private;
+       if (crtc_funcs && crtc_funcs->atomic_begin)
+               crtc_funcs->atomic_begin(crtc);
+
+       drm_for_each_plane_mask(plane, crtc->dev, plane_mask) {
+               struct drm_plane_state *old_plane_state =
+                       drm_atomic_get_existing_plane_state(old_state, plane);
+               const struct drm_plane_helper_funcs *plane_funcs;
+
+               plane_funcs = plane->helper_private;
+
+               if (!old_plane_state || !plane_funcs)
+                       continue;
+
+               WARN_ON(plane->state->crtc && plane->state->crtc != crtc);
+
+               if (drm_atomic_plane_disabling(plane, old_plane_state) &&
+                   plane_funcs->atomic_disable)
+                       plane_funcs->atomic_disable(plane, old_plane_state);
+               else if (plane->state->crtc ||
+                        drm_atomic_plane_disabling(plane, old_plane_state))
+                       plane_funcs->atomic_update(plane, old_plane_state);
+       }
+
+       if (crtc_funcs && crtc_funcs->atomic_flush)
+               crtc_funcs->atomic_flush(crtc);
+}
+EXPORT_SYMBOL(drm_atomic_helper_commit_planes_on_crtc);
+
 /**
  * drm_atomic_helper_cleanup_planes - cleanup plane resources after commit
  * @dev: DRM device

diff --git a/include/drm/drm_atomic_helper.h b/include/drm/drm_atomic_helper.h
index 6ee0ee5b61432471e6304e0509d1824885c81f3d..cc1fee8a12d0a5e71babb3626644604618b987ba 100644 (file)
--- a/include/drm/drm_atomic_helper.h
+++ b/include/drm/drm_atomic_helper.h
@@ -58,6 +58,7 @@ void drm_atomic_helper_commit_planes(struct drm_device *dev,
                                     struct drm_atomic_state *state);
 void drm_atomic_helper_cleanup_planes(struct drm_device *dev,
                                      struct drm_atomic_state *old_state);
+void drm_atomic_helper_commit_planes_on_crtc(struct drm_crtc_state *old_crtc_state);
 
 void drm_atomic_helper_swap_state(struct drm_device *dev,
                                  struct drm_atomic_state *state);