drm/atomic-helper: Set fence deadline for vblank

For an atomic commit updating a single CRTC (ie. a pageflip) calculate
the next vblank time, and inform the fence(s) of that deadline.

v2: Comment typo fix (danvet)
v3: If there are multiple CRTCs, consider the time of the soonest vblank

Signed-off-by: Rob Clark <robdclark@chromium.org>
Reviewed-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 d579fd8..28e3f2c 100644 (file)
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -1511,6 +1511,41 @@ void drm_atomic_helper_commit_modeset_enables(struct drm_device *dev,
 }
 EXPORT_SYMBOL(drm_atomic_helper_commit_modeset_enables);
 
+/*
+ * For atomic updates which touch just a single CRTC, calculate the time of the
+ * next vblank, and inform all the fences of the deadline.
+ */
+static void set_fence_deadline(struct drm_device *dev,
+                              struct drm_atomic_state *state)
+{
+       struct drm_crtc *crtc;
+       struct drm_crtc_state *new_crtc_state;
+       struct drm_plane *plane;
+       struct drm_plane_state *new_plane_state;
+       ktime_t vbltime = 0;
+       int i;
+
+       for_each_new_crtc_in_state (state, crtc, new_crtc_state, i) {
+               ktime_t v;
+
+               if (drm_crtc_next_vblank_start(crtc, &v))
+                       continue;
+
+               if (!vbltime || ktime_before(v, vbltime))
+                       vbltime = v;
+       }
+
+       /* If no CRTCs updated, then nothing to do: */
+       if (!vbltime)
+               return;
+
+       for_each_new_plane_in_state (state, plane, new_plane_state, i) {
+               if (!new_plane_state->fence)
+                       continue;
+               dma_fence_set_deadline(new_plane_state->fence, vbltime);
+       }
+}
+
 /**
  * drm_atomic_helper_wait_for_fences - wait for fences stashed in plane state
  * @dev: DRM device
@@ -1540,6 +1575,8 @@ int drm_atomic_helper_wait_for_fences(struct drm_device *dev,
        struct drm_plane_state *new_plane_state;
        int i, ret;
 
+       set_fence_deadline(dev, state);
+
        for_each_new_plane_in_state(state, plane, new_plane_state, i) {
                if (!new_plane_state->fence)
                        continue;