1 files changed, 62 insertions, 0 deletions
diff --git a/drm/UEventListener.cpp b/drm/UEventListener.cpp
new file mode 100644
index 0000000..b56b8e1
--- /dev/null
+++ b/drm/UEventListener.cpp
@@ -0,0 +1,62 @@
+/*
+ * Copyright (C) 2016 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 "hwc-uevent-listener"
+
+#include "UEventListener.h"
+
+#include <cerrno>
+
+#include "utils/log.h"
+
+/* Originally defined in system/core/libsystem/include/system/graphics.h as
+ * #define HAL_PRIORITY_URGENT_DISPLAY (-8)*/
+constexpr int kHalPriorityUrgentDisplay = -8;
+
+namespace android {
+
+UEventListener::UEventListener()
+    : Worker("uevent-listener", kHalPriorityUrgentDisplay){};
+
+int UEventListener::Init() {
+  uevent_ = UEvent::CreateInstance();
+  if (!uevent_) {
+    return -ENODEV;
+  }
+
+  return InitWorker();
+}
+
+void UEventListener::Routine() {
+  while (true) {
+    auto uevent_str = uevent_->ReadNext();
+
+    if (!hotplug_handler_ || !uevent_str)
+      continue;
+
+    bool drm_event = uevent_str->find("DEVTYPE=drm_minor") != std::string::npos;
+    bool hotplug_event = uevent_str->find("HOTPLUG=1") != std::string::npos;
+
+    if (drm_event && hotplug_event) {
+      constexpr useconds_t kDelayAfterUeventUs = 200000;
+      /* We need some delay to ensure DrmConnector::UpdateModes() will query
+       * correct modes list, otherwise at least RPI4 board may report 0 modes */
+      usleep(kDelayAfterUeventUs);
+      hotplug_handler_();
+    }
+  }
+}
+}  // namespace android