commit b864ccf845e5a228367c7dcd75ea8e16c6154b52
author Drew Davenport <ddavenport@google.com> Wed Jan 22 14:57:36 2025 -0700
committer Drew Davenport <ddavenport@google.com> Fri Jan 24 14:12:24 2025 -0700
tree b204aa654e49a72bb53d1c55567f84f1ba6c7362
parent 7f356c85011ab2d06203185ec1213a7b189f7f51

drm_hwcomposer: Remove HWC2 usage for Present

Add HwcDisplay::PresentStagedComposition to commit the changes that have
been previously validated through ValidateStagedComposition.

Drop usage of legacy HWC2 api in ComposerClient.cpp for DisplayCommand
present commands.

Change-Id: I0b7fcd4b664bf707f468cd40b1fefdfdd963f7f7
Signed-off-by: Drew Davenport <ddavenport@google.com>

hwc2_device/HwcDisplay.cpp

diff --git a/hwc2_device/HwcDisplay.cpp b/hwc2_device/HwcDisplay.cpp
index 9fbd6b9..c0fc3c5 100644
--- a/hwc2_device/HwcDisplay.cpp
+++ b/hwc2_device/HwcDisplay.cpp
@@ -401,6 +401,29 @@
   return changed_layers;
 }
 
+auto HwcDisplay::AcceptValidatedComposition() -> void {
+  for (std::pair<const hwc2_layer_t, HwcLayer> &l : layers_) {
+    l.second.AcceptTypeChange();
+  }
+}
+
+auto HwcDisplay::PresentStagedComposition(
+    int32_t *out_present_fence, std::vector<ReleaseFence> *out_release_fences)
+    -> HWC2::Error {
+  auto error = PresentDisplay(out_present_fence);
+  if (error != HWC2::Error::None || *out_present_fence == -1) {
+    return error;
+  }
+
+  for (auto &l : layers_) {
+    if (!l.second.GetPriorBufferScanOutFlag() || !present_fence_) {
+      continue;
+    }
+    out_release_fences->emplace_back(l.first, DupFd(present_fence_));
+  }
+  return error;
+}
+
 void HwcDisplay::SetPipeline(std::shared_ptr<DrmDisplayPipeline> pipeline) {
   Deinit();
 

hwc2_device/HwcDisplay.h

diff --git a/hwc2_device/HwcDisplay.h b/hwc2_device/HwcDisplay.h
index 9c113fd..8dc059c 100644
--- a/hwc2_device/HwcDisplay.h
+++ b/hwc2_device/HwcDisplay.h
@@ -95,6 +95,17 @@
   using ChangedLayer = std::pair<hwc2_layer_t, HWC2::Composition>;
   auto ValidateStagedComposition() -> std::vector<ChangedLayer>;
 
+  // Mark previously validated properties as ready to present.
+  auto AcceptValidatedComposition() -> void;
+
+  // Present previously staged properties, and return fences to indicate when
+  // the new content has been presented, and when the previous buffers have
+  // been released.
+  using ReleaseFence = std::pair<hwc2_layer_t, int32_t>;
+  auto PresentStagedComposition(int32_t *out_present_fence,
+                                std::vector<ReleaseFence> *out_release_fences)
+      -> HWC2::Error;
+
   // HWC2 Hooks - these should not be used outside of the hwc2 device.
   HWC2::Error AcceptDisplayChanges();
   HWC2::Error CreateLayer(hwc2_layer_t *layer);