Merge tag 'dma-fence-deadline' of https://gitlab.freedesktop.org/drm/msm into drm-next

This series adds a deadline hint to fences, so realtime deadlines
such as vblank can be communicated to the fence signaller for power/
frequency management decisions.

This is partially inspired by a trick i915 does, but implemented
via dma-fence for a couple of reasons:

1) To continue to be able to use the atomic helpers
2) To support cases where display and gpu are different drivers

See https://patchwork.freedesktop.org/series/93035/

This does not yet add any UAPI, although this will be needed in
a number of cases:

1) Workloads "ping-ponging" between CPU and GPU, where we don't
   want the GPU freq governor to interpret time stalled waiting
   for GPU as "idle" time
2) Cases where the compositor is waiting for fences to be signaled
   before issuing the atomic ioctl, for example to maintain 60fps
   cursor updates even when the GPU is not able to maintain that
   framerate.

Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
From: Rob Clark <robdclark@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/CAF6AEGt5nDQpa6J86V1oFKPA30YcJzPhAVpmF7N1K1g2N3c=Zg@mail.gmail.com

1 files changed, 37 insertions, 0 deletions

diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
index 8606876f7233..d4d2a2ce40f8 100644
--- 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;