System properties in SurfaceFlinger

The ConfigStore HAL remains in AOSP to support legacy vendor partitions. On devices running Android 10+, surfaceflinger first reads system properties. If no system property is defined for a config item in SurfaceFlingerProperties.sysprop, surfaceflinger falls back to the ConfigStore HAL.

Build flags and system properties

Each build flag in ConfigStore has a matching system property, as shown in the following table. For details on these properties, see frameworks/native/services/surfaceflinger/sysprop/ SurfaceFlingerProperties.sysprop.

Use SurfaceFlingerProperties

The following examples show how to use the SurfaceFlingerProperties library and the Surface Flinger property ro.surface_flinger.vsync_event_phase_offset_ns.

To query the property's value, use its api_name as the function name.

Include SurfaceFlingerProperties in your build file, as follows:

cc_binary {
 name: "cc_client",
 srcs: ["baz.cpp"],
 shared_libs: ["SurfaceFlingerProperties"],
}
java_library {
 name: "JavaClient",
 srcs: ["foo/bar.java"],
 libs: ["SurfaceFlingerProperties"],
}

The following Java code snippet uses the ro.surface_flinger.vsync_event_phase_offset_ns system property:

importandroid.sysprop.SurfaceFlingerProperties;
...
staticvoidfoo(){
...
booleantemp=SurfaceFlingerProperties.vsync_event_phase_offset_ns().orElse(true);
...
}
...

The following C++ code snippet uses the ro.surface_flinger.vsync_event_phase_offset_ns system property:

#include <SurfaceFlingerProperties.sysprop.h>
usingnamespaceandroid::sysprop;
...
voidbar(){
...
booltemp=SurfaceFlingerProperties::vsync_event_phase_offset_ns(true);
...
}
...