+ * Instead, run a separate process with a different classpath and LD_PRELOAD just to set the display power mode. + *
+ * Since the client must not block, and calling/joining a process is blocking (this specific one takes a few hundred milliseconds to complete), + * this class uses an internal thread to execute the requests asynchronously, and serialize them (so that two successive requests are guaranteed to + * be executed in order). In addition, it only executes the last pending request (setting power mode to value X then to value Y is equivalent to + * just setting it to value Y). + */ +public final class DisplayPowerMode { + + private static final Proxy PROXY = new Proxy(); + + private static final class Proxy implements Runnable { + + private Thread thread; + private int requestedMode = -1; + private boolean stopped; + + synchronized void requestMode(int mode) { + if (thread == null) { + thread = new Thread(this, "DisplayPowerModeProxy"); + thread.setDaemon(true); + thread.start(); + } + requestedMode = mode; + notify(); + } + + void stopAndJoin() { + boolean hasThread; + synchronized (this) { + hasThread = thread != null; + if (thread != null) { + stopped = true; + notify(); + } + } + + if (hasThread) { + // Join the thread without holding the mutex (that would cause a deadlock) + try { + thread.join(); + } catch (InterruptedException e) { + Ln.e("Thread join interrupted", e); + } + } + } + + @Override + public void run() { + try { + int mode; + while (true) { + synchronized (this) { + while (!stopped && requestedMode == -1) { + wait(); + } + mode = requestedMode; + requestedMode = -1; + } + + // Even if stopped, the last request must be executed to restore the display power mode to normal + if (mode == -1) { + return; + } + + try { + Process process = executeSystemServerSetDisplayPowerMode(mode); + int status = process.waitFor(); + if (status != 0) { + Ln.e("Set display power mode failed remotely: status=" + status); + } + } catch (Exception e) { + Ln.e("Failed to execute process", e); + } + } + } catch (InterruptedException e) { + // end of thread + } + } + } + + private DisplayPowerMode() { + // not instantiable + } + + // Called from the scrcpy process + public static void setRemoteDisplayPowerMode(int mode) { + PROXY.requestMode(mode); + } + + public static void stopAndJoin() { + PROXY.stopAndJoin(); + } + + // Called from the proxy thread in the scrcpy process + private static Process executeSystemServerSetDisplayPowerMode(int mode) throws IOException { + String[] ldPreloadLibs = {"/system/lib64/libandroid_servers.so"}; + String[] cmd = {"app_process", "/", DisplayPowerMode.class.getName(), String.valueOf(mode)}; + + ProcessBuilder builder = new ProcessBuilder(cmd); + builder.environment().put("LD_PRELOAD", String.join(" ", ldPreloadLibs)); + builder.environment().put("CLASSPATH", Server.SERVER_PATH + ":/system/framework/services.jar"); + return builder.start(); + } + + // Executed in the DisplayPowerMode-specific process + @SuppressLint({"PrivateApi", "SoonBlockedPrivateApi"}) + private static void setDisplayPowerModeUsingDisplayControl(int mode) throws Exception { + System.loadLibrary("android_servers"); + + @SuppressLint("PrivateApi") + Class displayControlClass = Class.forName("com.android.server.display.DisplayControl"); + Method getPhysicalDisplayIdsMethod = displayControlClass.getDeclaredMethod("getPhysicalDisplayIds"); + Method getPhysicalDisplayTokenMethod = displayControlClass.getDeclaredMethod("getPhysicalDisplayToken", long.class); + + Class surfaceControlClass = Class.forName("android.view.SurfaceControl"); + Method setDisplayPowerModeMethod = surfaceControlClass.getDeclaredMethod("setDisplayPowerMode", IBinder.class, int.class); + + long[] displayIds = (long[]) getPhysicalDisplayIdsMethod.invoke(null); + for (long displayId : displayIds) { + Object token = getPhysicalDisplayTokenMethod.invoke(null, displayId); + setDisplayPowerModeMethod.invoke(null, token, mode); + } + } + + public static void main(String... args) { + Ln.disableSystemStreams(); + Ln.initLogLevel(Ln.Level.DEBUG); + + int status = run(args) ? 0 : 1; + System.exit(status); + } + + private static boolean run(String... args) { + if (args.length != 1) { + Ln.e("Exactly one argument expected: the value of one of the SurfaceControl.POWER_MODE_* constants (typically 0 or 2)"); + return false; + } + + try { + int mode = Integer.parseInt(args[0]); + setDisplayPowerModeUsingDisplayControl(mode); + return true; + } catch (Throwable e) { + Ln.e("Could not set display power mode", e); + return false; + } + } +} diff --git a/server/src/main/java/com/genymobile/scrcpy/wrappers/SurfaceControl.java b/server/src/main/java/com/genymobile/scrcpy/wrappers/SurfaceControl.java index 595ee6d477..98259e7ff5 100644 --- a/server/src/main/java/com/genymobile/scrcpy/wrappers/SurfaceControl.java +++ b/server/src/main/java/com/genymobile/scrcpy/wrappers/SurfaceControl.java @@ -139,6 +139,15 @@ private static Method getGetPhysicalDisplayIdsMethod() throws NoSuchMethodExcept return getPhysicalDisplayIdsMethod; } + public static boolean hasPhysicalDisplayIdsMethod() { + try { + getGetPhysicalDisplayIdsMethod(); + return true; + } catch (NoSuchMethodException e) { + return false; + } + } + public static long[] getPhysicalDisplayIds() { try { Method method = getGetPhysicalDisplayIdsMethod();