Add atom reporting for refresh rate changes

Add DisplayRefreshRatesChangedAtomReporter, which reports the changed
refresh rates of all the active displays managed by drm_hwcomposer.

Change-Id: I03a81c667c44160dc319a899a3bd9a8bc527a382

.ci/Makefile

@@ -103,6 +103,7 @@ SKIP_FILES := \
     drm/DrmDisplayPipelineTest.cpp \
     stats/CompositionStatsTest.cpp \
     stats/CompositionStatsAtomReporterDesktop.cpp \
+    stats/DisplayRefreshRatesChangedAtomReporterDesktop.cpp \
 
 BUILD_FILES_AUTO := $(shell find -L $(SRC_DIR) -not -path '*/\.*' -not -path '*/tests/test_include/*' -path '*.cpp')
 SKIP_FILES_path := $(foreach file,$(SKIP_FILES),$(SRC_DIR)/$(file))

Android.bp

@@ -345,6 +345,7 @@ drm_hwcomposer_atom_reporter_library {
                 srcs: [
                     "compositor/FlatteningEventAtomReporterDesktop.cpp",
                     "stats/CompositionStatsAtomReporterDesktop.cpp",
+                    "stats/DisplayRefreshRatesChangedAtomReporterDesktop.cpp",
                 ],
                 shared_libs: [
                     "android.frameworks.stats-V2-ndk",
@@ -356,6 +357,7 @@ drm_hwcomposer_atom_reporter_library {
                 srcs: [
                     "compositor/FlatteningEventAtomReporter.cpp",
                     "stats/CompositionStatsAtomReporter.cpp",
+                    "stats/DisplayRefreshRatesChangedAtomReporter.cpp",
                 ],
             },
         },

drm/DrmHwc.cpp

@@ -72,7 +72,11 @@ std::string DumpDisplayStats(const HwcDisplay *display,
 }
 }  // namespace
 
-DrmHwc::DrmHwc() : resource_manager_(this), dump_stats_tracker_(this) {};
+DrmHwc::DrmHwc()
+    : resource_manager_(this),
+      dump_stats_tracker_(this),
+      refresh_rates_reporter_(
+          DisplayRefreshRatesChangedAtomReporter::Create()) {};
 
 /* Must be called after every display attach/detach cycle */
 void DrmHwc::FinalizeDisplayBinding() {
@@ -274,4 +278,18 @@ void DrmHwc::DeinitDisplays() {
   }
 }
 
+void DrmHwc::LogRefreshRateChanges() {
+  std::vector<int32_t> refresh_rates;
+  refresh_rates.reserve(displays_.size());
+  for (const auto &[_, display] : displays_) {
+    if (const HwcDisplayConfig *config = display->GetCurrentConfig(); config) {
+      refresh_rates.push_back(
+          static_cast<int32_t>(lround(config->mode.GetVRefresh())));
+    }
+  }
+
+  if (refresh_rates_reporter_)
+    refresh_rates_reporter_->UpdateRefreshRates(refresh_rates);
+}
+
 }  // namespace android::drm_hwcomposer

drm/DrmHwc.h

@@ -19,6 +19,7 @@
 #include "drm/ResourceManager.h"
 #include "hwc/HwcDisplay.h"
 #include "stats/CompositionStats.h"
+#include "stats/DisplayRefreshRatesChangedAtomReporter.h"
 
 namespace android::drm_hwcomposer {
 
@@ -85,6 +86,9 @@ class DrmHwc : public PipelineToFrontendBindingInterface,
   void NotifyDisplayLinkStatus(
       std::shared_ptr<DrmDisplayPipeline> pipeline) override;
 
+  // Should be done for all successful modesets (full and seamless).
+  void LogRefreshRateChanges();
+
  protected:
   auto &Displays() {
     return displays_;
@@ -100,6 +104,9 @@ class DrmHwc : public PipelineToFrontendBindingInterface,
 
   DisplayHandle last_display_handle_ = kPrimaryDisplay;
   CompositionStatsTracker dump_stats_tracker_;
+
+  std::unique_ptr<DisplayRefreshRatesChangedAtomReporter>
+      refresh_rates_reporter_;
 };
 
 }  // namespace android::drm_hwcomposer

hwc3/ComposerClient.cpp

@@ -1318,6 +1318,7 @@ ndk::ScopedAStatus ComposerClient::setActiveConfigWithConstraints(
       return ToBinderStatus(hwc3::Error::kBadConfig);
     #endif
     case HwcDisplay::ConfigError::kNone:
+      hwc_->LogRefreshRateChanges();
       return ndk::ScopedAStatus::ok();
   }
 }

meson.build

@@ -24,6 +24,7 @@ src_common = files(
     'stats/CompositionStats.cpp',
     'stats/CompositionStatsAtomReporter.cpp',
     'stats/CompositionStatsPoller.cpp',
+    'stats/DisplayRefreshRatesChangedAtomReporter.cpp',
     'utils/fd.cpp',
     'utils/LibdisplayEdidWrapper.cpp',
     'utils/properties.cpp',

stats/DisplayRefreshRatesChangedAtomReporter.cpp

@@ -0,0 +1,31 @@
+/*
+ * Copyright (C) 2025 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#define LOG_TAG "drmhwc"
+
+#include "DisplayRefreshRatesChangedAtomReporter.h"
+
+#include "utils/log.h"
+
+namespace android::drm_hwcomposer {
+
+std::unique_ptr<DisplayRefreshRatesChangedAtomReporter>
+DisplayRefreshRatesChangedAtomReporter::Create() {
+  ALOGI("Atom reporting is not enabled.");
+  return {};
+}
+
+}  // namespace android::drm_hwcomposer

stats/DisplayRefreshRatesChangedAtomReporter.h

@@ -0,0 +1,31 @@
+/*
+ * Copyright (C) 2025 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <memory>
+#include <vector>
+
+namespace android::drm_hwcomposer {
+class DisplayRefreshRatesChangedAtomReporter {
+ public:
+  static std::unique_ptr<DisplayRefreshRatesChangedAtomReporter> Create();
+
+  virtual void UpdateRefreshRates(std::vector<int32_t> refresh_rates) = 0;
+  virtual ~DisplayRefreshRatesChangedAtomReporter() = default;
+};
+
+}  // namespace android::drm_hwcomposer

stats/DisplayRefreshRatesChangedAtomReporterDesktop.cpp

@@ -0,0 +1,83 @@
+/*
+ * Copyright (C) 2025 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#define LOG_TAG "drmhwc"
+// #define NLOG_DEBUG 0
+
+#include "DisplayRefreshRatesChangedAtomReporter.h"
+
+#include <cinttypes>
+#include <thread>
+
+#include <aidl/android/frameworks/stats/IStats.h>
+#include <android/binder_manager.h>
+
+#include "desktopatoms.h"
+#include "utils/log.h"
+
+using aidl::android::frameworks::stats::IStats;
+using aidl::android::frameworks::stats::VendorAtom;
+namespace DesktopAtoms = android::vendor::google::desktop::stats::DesktopAtoms;
+
+namespace android::drm_hwcomposer {
+namespace {
+
+const std::string kStatsServiceName = std::string(IStats::descriptor)
+                                          .append("/default");
+
+// Use a private implementation of DisplayRefreshRatesChangedAtomReporter to
+// avoid leaking the IStats interface through the public api.
+class DisplayRefreshRatesChangedAtomReporterDesktop
+    : public DisplayRefreshRatesChangedAtomReporter {
+ public:
+  void UpdateRefreshRates(std::vector<int32_t> refresh_rates) override {
+    if (refresh_rates == last_refresh_rates_) {
+      return;
+    }
+
+    last_refresh_rates_ = refresh_rates;
+
+    // The order of the arguments to createVendorAtom is determined by the
+    // proto definition in libdesktopatoms.
+    const char* deprecated_reverse_domain_name = "";
+    const VendorAtom vendor_atom = DesktopAtoms::
+        createVendorAtom(DesktopAtoms::DISPLAY_REFRESH_RATES_CHANGED,
+                         deprecated_reverse_domain_name, refresh_rates);
+
+    auto stats_service = IStats::fromBinder(ndk::SpAIBinder(
+        AServiceManager_checkService(kStatsServiceName.c_str())));
+    ALOGE_IF(stats_service == nullptr, "Failed to get IStats service");
+    if (stats_service) {
+      const ndk::ScopedAStatus ret = stats_service->reportVendorAtom(
+          vendor_atom);
+    }
+  }
+
+ private:
+  std::vector<int32_t> last_refresh_rates_;
+};
+}  // namespace
+
+std::unique_ptr<DisplayRefreshRatesChangedAtomReporter>
+DisplayRefreshRatesChangedAtomReporter::Create() {
+  if (!AServiceManager_isDeclared(kStatsServiceName.c_str())) {
+    ALOGW("Stats service is not declared.");
+    return nullptr;
+  }
+  return std::make_unique<DisplayRefreshRatesChangedAtomReporterDesktop>();
+}
+
+}  // namespace android::drm_hwcomposer