frameworks/base/services/core/java/com/android/server/display/LocalDisplayAdapter.java

final class LocalDisplayAdapter extends DisplayAdapter {

} else {

mInfo.type = Display.TYPE_HDMI;
mInfo.flags |= DisplayDeviceInfo.FLAG_PRESENTATION;
+boolean noRotate = "0".equals(SystemProperties.get("ro.sf.hwrotation"));
+if(noRotate && mBuiltInDisplayId == SurfaceControl.BUILT_IN_DISPLAY_ID_HDMI){
+if (SystemProperties.getBoolean("ro.rotation.external", false)) {
＋mInfo.flags |= DisplayDeviceInfo.FLAG_ROTATES_WITH_CONTENT;
+ }
＋　String value = SystemProperties.get("ro.orientation.einit");
＋if ("0".equals(value)) {
＋ mInfo.rotation = Surface.ROTATION_0;
+} else if ("90".equals(value)) {
＋mInfo.rotation = Surface.ROTATION_90;
+} else if ("180".equals(value)) {
 +mInfo.rotation = Surface.ROTATION_180;
＋} else if ("270".equals(value)) {
＋mInfo.rotation = Surface.ROTATION_270;
＋}
＋}
 

frameworks/native/services/surfaceflinger/DisplayDevice.cpp

void DisplayDevice::setProjection(int orientation,
mClientOrientation = orientation;
orientation = (mHardwareOrientation + orientation) % 4;
 }
+ if (mType == DisplayDevice::DISPLAY_EXTERNAL) {
+ mClientOrientation = orientation;
+ if (orientation %2 == 1)
+ frame = Rect(0,0,getHeight(),getWidth());
+ }

device/rockchip/rk3288/system.prop

＋ro.same.orientation=true
+ro.rotation.external=true
+ro.orientation.einit=90