[PATCH v9 11/15] drm/atomic-helper: Set fence deadline for vblank

Rob Clark
2023-03-02T23:55:03Z

From: Rob Clark <robdclark@chromium.org>

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)

Signed-off-by: Rob Clark <robdclark@chromium.org>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Rob Clark <robdclark@chromium.org>
---
drivers/gpu/drm/drm_atomic_helper.c | 36 +++++++++++++++++++++++++++++
1 file changed, 36 insertions(+)

diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
index d579fd8f7cb8..d8ee98ce2fc5 100644
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -1511,6 +1511,40 @@ 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, *wait_crtc = NULL;
+ struct drm_crtc_state *new_crtc_state;
+ struct drm_plane *plane;
+ struct drm_plane_state *new_plane_state;
+ ktime_t vbltime;
+ int i;
+
+ for_each_new_crtc_in_state (state, crtc, new_crtc_state, i) {
+ if (wait_crtc)
+ return;
+ wait_crtc = crtc;
+ }
+
+ /* If no CRTCs updated, then nothing to do: */
+ if (!wait_crtc)
+ return;
+
+ if (drm_crtc_next_vblank_start(wait_crtc, &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 +1574,8 @@ 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;
--
2.39.1