drm_hwcomposer: Check "Present Not Reliable" property
Check the "Present Not Reliable" property to determine if the capability
PRESENT_FENCE_IS_NOT_RELIABLE should be enabled or not.
The virtio gpu module sends frames to the host as fast as possible and
does not emulate "real display timing". Devices using the virtio gpu
module (for example, the virtual Android device Cuttlefish) should set
the following property to "true" to enable the capability:
ro.vendor.hwc.drm.present_not_reliable.enabled
For example, in an Android BoardConfig.mk:
PRODUCT_VENDOR_PROPERTIES += \
vendor.hwc.drm.present_not_reliable.enabled=true
Signed-off-by: Tim Van Patten <timvp@google.com>
diff --git a/utils/properties.cpp b/utils/properties.cpp
new file mode 100644
index 0000000..4547e74
--- /dev/null
+++ b/utils/properties.cpp
@@ -0,0 +1,27 @@
+/*
+ * Copyright (C) 2023 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.
+ */
+
+#include "properties.h"
+
+/**
+ * @brief Determine if the "Present Not Reliable" property is enabled.
+ *
+ * @return boolean
+ */
+auto Properties::IsPresentFenceNotReliable() -> bool {
+ return (property_get_bool("ro.vendor.hwc.drm.present_fence_not_reliable",
+ 0) != 0);
+}