drm_hwcomposer: Add out-fence support

Add support for out-fences through the OUT_FENCE_PTR property.
Out-fences signal when their associated buffer may be read by a device.

Signed-off-by: Robert Foss <robert.foss@collabora.com>
Reviewed-by: Sean Paul <seanpaul@chromium.org>

1 files changed, 9 insertions, 0 deletions

diff --git a/drmdisplaycomposition.h b/drmdisplaycomposition.h
index 13da19d..470bf7e 100644
--- a/drmdisplaycomposition.h
+++ b/drmdisplaycomposition.h
@@ -179,6 +179,14 @@ class DrmDisplayComposition {
     return planner_;
   }
 
+  int take_out_fence() {
+    return out_fence_.Release();
+  }
+
+  void set_out_fence(int out_fence) {
+    out_fence_.Set(out_fence);
+  }
+
   void Dump(std::ostringstream *out) const;
 
  private:
@@ -205,6 +213,7 @@ class DrmDisplayComposition {
   int timeline_current_ = 0;
   int timeline_squash_done_ = 0;
   int timeline_pre_comp_done_ = 0;
+  UniqueFd out_fence_ = -1;
 
   bool geometry_changed_;
   std::vector<DrmHwcLayer> layers_;