Add VSync.

README

@@ -4,7 +4,7 @@ Most features of full VDPAU are missing, only decoding of h264, mpeg1 and
 mpeg2 and output of software-decoded videos will work.
 Output bypasses X video driver, hence don't try to use Xv
 at the same time.
-Only tested with mplayer, if other players need unimplemented functions
+Only tested with mplayer and mpv, if other players need unimplemented functions
 something will fail.
 
    $ make
@@ -23,6 +23,9 @@ To enable OSD support for e.g. subtitles, set VDPAU_OSD environment
 variable to 1:
    $ export VDPAU_OSD=1
 
+To enable experimental VSYNC support, set VDPAU_VSYNC environment variable to 1:
+   $ export VDPAU_VSYNC=1
+
 This partly breaks X11 integration due to hardware limitations. The video
 area can't be overlapped by other windows. For fullscreen use this is no
 problem.

device.c

@@ -44,6 +44,7 @@ VdpStatus vdp_imp_device_create_x11(Display *display,
 		return VDP_STATUS_ERROR;
 	}
 
+	// Get environment variables
 	char *env_vdpau_osd = getenv("VDPAU_OSD");
 	if (env_vdpau_osd && strncmp(env_vdpau_osd, "1", 1) == 0)
 	{
@@ -54,6 +55,15 @@ VdpStatus vdp_imp_device_create_x11(Display *display,
 			VDPAU_DBG("Failed to open /dev/g2d! OSD disabled.");
 	}
 
+	char *env_vdpau_vsync = getenv("VDPAU_VSYNC");
+	if (env_vdpau_vsync && strncmp(env_vdpau_vsync, "1", 1) == 0)
+	{
+		dev->vsync_enabled = 1;
+		VDPAU_DBG("VSync enabled.");
+	}
+	else
+		VDPAU_DBG("VSync disabled.");
+
 	*get_proc_address = &vdp_get_proc_address;
 
 	return VDP_STATUS_OK;

presentation_queue.c

@@ -17,16 +17,19 @@
  *
  */
 
-#include "vdpau_private.h"
-#include <time.h>
 #include <fcntl.h>
+#include <inttypes.h>
+#include <linux/fb.h>
 #include <pthread.h>
 #include <unistd.h>
 #include <string.h>
 #include <sys/ioctl.h>
-#include "sunxi_disp_ioctl.h"
+#include <time.h>
+
 #include "queue.h"
 #include "rgba.h"
+#include "sunxi_disp_ioctl.h"
+#include "vdpau_private.h"
 #include "ve.h"
 
 static pthread_t presentation_thread_id;
@@ -253,6 +256,16 @@ static VdpStatus do_presentation_queue_display(Task *task)
 
 static void *presentation_thread(void *param)
 {
+	queue_ctx_t *q = param;
+	int fd_fb = 0;
+
+	if (q->device->vsync_enabled)
+	{
+		fd_fb = open("/dev/fb0", O_RDWR);
+		if (!fd_fb)
+			VDPAU_DGB("Error opening framebuffer device /dev/fb0");
+	}
+
 	while (1) {
 		int64_t timeout;
 		Task *task = q_peek_head(queue);
@@ -261,6 +274,14 @@ static void *presentation_thread(void *param)
 			clock_gettime(CLOCK_REALTIME, &now);
 			// timeout is the difference between now and scheduled time
 			timeout = (task->when.tv_sec - now.tv_sec) * 1000 * 1000 + (task->when.tv_nsec - now.tv_nsec) / 1000;
+
+			// do the VSync
+			if (q->device->vsync_enabled)
+			{
+				if ((fd_fb) && (ioctl(fd_fb, FBIO_WAITFORVSYNC, 0)))
+					VDPAU_DBG("VSync failed");
+			}
+
 			if (timeout <= 0) { // task is ready to go
 				// run the task
 				do_presentation_queue_display(task);

vdpau_private.h

@@ -39,6 +39,7 @@ typedef struct
 	int fd;
 	int g2d_fd;
 	int osd_enabled;
+	int vsync_enabled;
 } device_ctx_t;
 
 typedef struct