Implement HAVE_LCD_ENABLE and lcd_update_rect(). When Rockbox runs in the background

this greatly reduces CPU load. lcd_update_rect shoves a bit as well.

CPU usage with Rockbox in background is between 3% (with a 200kbps vbr mp3) and 12% (320kbps cbr mp3), so it's low but still dependent on codecs and even particular files.
Driving a WPS with peakmeter, e.g. the builtin one, adds about 30% cpu usage.

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@27689 a1c6a512-1295-4272-9138-f99709370657

android/src/org/rockbox/RockboxActivity.java

@@ -78,6 +78,7 @@ public class RockboxActivity extends Activity {
     public void onResume()
     {
     	super.onResume();
+    	
     	if (RockboxService.fb != null)
     	{
     		try {
@@ -91,9 +92,31 @@ public class RockboxActivity extends Activity {
     		} catch (Exception e) {
     			LOG(e.toString());
     		}
+    		RockboxService.fb.resume();
     	}
     }
     
+    /* this is also called when the backlight goes off,
+     * which is nice 
+     */
+    @Override
+    protected void onPause() {
+    	super.onPause();
+    	RockboxService.fb.suspend();
+    }
+    
+    @Override
+    protected void onStop() {
+    	super.onStop();
+    	RockboxService.fb.suspend();
+    }
+    
+    @Override
+    protected void onDestroy() {
+    	super.onDestroy();
+    	RockboxService.fb.suspend();
+    }
+
 	private void LOG(CharSequence text)
 	{
 		Log.d("Rockbox", (String) text);

android/src/org/rockbox/RockboxFramebuffer.java

@@ -34,21 +34,11 @@ public class RockboxFramebuffer extends View
 {
 	private Bitmap btm;
     private ByteBuffer native_buf;
-    private Handler update_handler;
-    private Runnable cb;
 
 
 	public RockboxFramebuffer(Context c)
 	{
 		super(c);
-		update_handler = new Handler();
-		cb = new Runnable() {
-			public void run()
-			{
-				btm.copyPixelsFromBuffer(native_buf);
-				invalidate();
-			}
-		};
 		btm = null;
 	}
 
@@ -66,7 +56,16 @@ public class RockboxFramebuffer extends View
 	
 	public void java_lcd_update()
 	{
-		update_handler.post(cb);
+
+		btm.copyPixelsFromBuffer(native_buf);
+		postInvalidate();
+	}
+	
+	public void java_lcd_update_rect(int x, int y, int w, int h)
+	{
+		/* can't copy a partial buffer */
+		btm.copyPixelsFromBuffer(native_buf);
+		postInvalidate(x, y, x+w, y+h);
 	}
 
 	private void LOG(CharSequence text)
@@ -93,6 +92,18 @@ public class RockboxFramebuffer extends View
 		return true;
 	}
 	
+	/* the two below should only be called from the activity thread */
+	public void suspend()
+	{	/* suspend, Rockbox will not make any lcd updates */
+		set_lcd_active(0);
+	}
+	public void resume()
+	{	/* make updates again, the underlying function will 
+		 * send an event */
+		set_lcd_active(1);
+	}
+
+	public native void set_lcd_active(int active);
 	public native void pixelHandler(int x, int y);
 	public native void touchHandler(int down);
 }

firmware/export/config/application.h

@@ -53,6 +53,10 @@
 #define LCD_DEPTH  16
 #define LCD_PIXELFORMAT 565
 
+#if (CONFIG_PLATFORM & PLATFORM_ANDROID)
+#define HAVE_LCD_ENABLE
+#endif
+
 /* define this to indicate your device's keypad */
 #define HAVE_TOUCHSCREEN
 #define HAVE_BUTTON_DATA

firmware/target/hosted/android/lcd-android.c

@@ -31,6 +31,9 @@ extern jobject RockboxService_instance;
 
 static jobject Framebuffer_instance;
 static jmethodID java_lcd_update;
+static jmethodID java_lcd_update_rect;
+
+static bool display_on;
 
 void lcd_init_device(void)
 {
@@ -59,6 +62,10 @@ void lcd_init_device(void)
                                                    Framebuffer_class,
                                                    "java_lcd_update",
                                                    "()V");
+    java_lcd_update_rect = (*env_ptr)->GetMethodID(env_ptr,
+                                                   Framebuffer_class,
+                                                   "java_lcd_update_rect",
+                                                   "(IIII)V");
 
     /* map the framebuffer to a ByteBuffer, this way lcd updates will
      * be directly feched from the framebuffer */
@@ -70,21 +77,50 @@ void lcd_init_device(void)
                                Framebuffer_instance,
                                java_init_lcd,
                                LCD_WIDTH, LCD_HEIGHT, buf);
+    display_on = true;
 }
 
-void lcd_update()
+void lcd_update(void)
 {
     /* tell the system we're ready for drawing */
+    if (display_on)
         (*env_ptr)->CallVoidMethod(env_ptr, Framebuffer_instance, java_lcd_update);
 }
 
 void lcd_update_rect(int x, int y, int height, int width)
 {
-    /* can't do partial updates yet */
-    (void)x; (void)y; (void)height; (void)width;
-    lcd_update();
+    if (display_on)
+    {
+        (*env_ptr)->CallVoidMethod(env_ptr, Framebuffer_instance, java_lcd_update_rect,
+                                   x, y, height, width);
+    }
 }
 
+bool lcd_active(void)
+{
+    return display_on;
+}
+
+/*
+ * (un)block lcd updates.
+ *
+ * Notice: This is called from the activity thread, so take it
+ * as interrupt context and take care what the event callback does
+ * (it shouldn't block in particular
+ *
+ * the 1s are needed due to strange naming conventions...
+ **/
+JNIEXPORT void JNICALL
+Java_org_rockbox_RockboxFramebuffer_set_1lcd_1active(JNIEnv *e,
+                                                     jobject this,
+                                                     jint active)
+{
+    (void)e;
+    (void)this;
+    display_on = active != 0;
+    if (active)
+        send_event(LCD_EVENT_ACTIVATION, NULL);
+}
 /* below is a plain copy from lcd-sdl.c */
 
 /**