sandbox: video: Speed up video output

At present there are many situations where sandbox syncs the display to
the SDL frame buffer. This is a very expensive operation but is only
needed every now and then. Update video_sync() so that we can specify
whether this operation is really needed.

At present this flag is not used on other architectures. It could also
be used for reducing writeback-cache flushes but the benefit of that would
need to be investigated.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Anatolij Gustschin <agust@denx.de>

drivers/video/vidconsole-uclass.c

@@ -86,7 +86,7 @@ static int vidconsole_back(struct udevice *dev)
 		if (priv->ycur < 0)
 			priv->ycur = 0;
 	}
-	video_sync(dev->parent);
+	video_sync(dev->parent, false);
 
 	return 0;
 }
@@ -113,7 +113,7 @@ static void vidconsole_newline(struct udevice *dev)
 	}
 	priv->last_ch = 0;
 
-	video_sync(dev->parent);
+	video_sync(dev->parent, false);
 }
 
 static const struct vid_rgb colors[VID_COLOR_COUNT] = {
@@ -293,7 +293,7 @@ static void vidconsole_escape_char(struct udevice *dev, char ch)
 
 		if (mode == 2) {
 			video_clear(dev->parent);
-			video_sync(dev->parent);
+			video_sync(dev->parent, false);
 			priv->ycur = 0;
 			priv->xcur_frac = priv->xstart_frac;
 		} else {
@@ -449,7 +449,7 @@ static void vidconsole_putc(struct stdio_dev *sdev, const char ch)
 	struct udevice *dev = sdev->priv;
 
 	vidconsole_put_char(dev, ch);
-	video_sync(dev->parent);
+	video_sync(dev->parent, false);
 }
 
 static void vidconsole_puts(struct stdio_dev *sdev, const char *s)
@@ -458,7 +458,7 @@ static void vidconsole_puts(struct stdio_dev *sdev, const char *s)
 
 	while (*s)
 		vidconsole_put_char(dev, *s++);
-	video_sync(dev->parent);
+	video_sync(dev->parent, false);
 }
 
 /* Set up the number of rows and colours (rotated drivers override this) */
@@ -547,7 +547,7 @@ static int do_video_puts(cmd_tbl_t *cmdtp, int flag, int argc,
 	for (s = argv[1]; *s; s++)
 		vidconsole_put_char(dev, *s);
 
-	video_sync(dev->parent);
+	video_sync(dev->parent, false);
 
 	return 0;
 }

drivers/video/video-uclass.c

@@ -128,7 +128,7 @@ void video_set_default_colors(struct video_priv *priv)
 }
 
 /* Flush video activity to the caches */
-void video_sync(struct udevice *vid)
+void video_sync(struct udevice *vid, bool force)
 {
 	/*
 	 * flush_dcache_range() is declared in common.h but it seems that some
@@ -147,7 +147,7 @@ void video_sync(struct udevice *vid)
 	struct video_priv *priv = dev_get_uclass_priv(vid);
 	static ulong last_sync;
 
-	if (get_timer(last_sync) > 10) {
+	if (force || get_timer(last_sync) > 10) {
 		sandbox_sdl_sync(priv->fb);
 		last_sync = get_timer(0);
 	}
@@ -162,7 +162,7 @@ void video_sync_all(void)
 	     dev;
 	     uclass_find_next_device(&dev)) {
 		if (device_active(dev))
-			video_sync(dev);
+			video_sync(dev, true);
 	}
 }
 

drivers/video/video_bmp.c

@@ -345,7 +345,7 @@ int video_bmp_display(struct udevice *dev, ulong bmp_image, int x, int y,
 		break;
 	};
 
-	video_sync(dev);
+	video_sync(dev, false);
 
 	return 0;
 }

include/video.h

@@ -131,8 +131,10 @@ void video_clear(struct udevice *dev);
  * buffer are displayed to the user.
  *
  * @dev:	Device to sync
+ * @force:	True to force a sync even if there was one recently (this is
+ *		very expensive on sandbox)
  */
-void video_sync(struct udevice *vid);
+void video_sync(struct udevice *vid, bool force);
 
 /**
  * video_sync_all() - Sync all devices' frame buffers with there hardware

test/dm/video.c

@@ -169,7 +169,7 @@ static int dm_test_video_ansi(struct unit_test_state *uts)
 
 	/* reference clear: */
 	video_clear(con->parent);
-	video_sync(con->parent);
+	video_sync(con->parent, false);
 	ut_asserteq(46, compress_frame_buffer(dev));
 
 	/* test clear escape sequence: [2J */