bgi: wait before flipping

Signed-off-by: Michael Olbrich <m.olbrich@pengutronix.de>

1 files changed, 13 insertions, 4 deletions

diff --git a/src/bgi.c b/src/bgi.c
index bfabfa5..78f1dfd 100644
--- a/src/bgi.c
+++ b/src/bgi.c
@@ -20,6 +20,7 @@
 
 static struct kms_fb *fb3d;
 static int crtc3d;
+static int can_wait;
 int do_wait_vblank;
 
 static struct fb_fix_screeninfo fix = {
@@ -106,6 +107,11 @@ static int wait_vblank(void)
 	struct timeval timeout = { .tv_sec = 0, .tv_usec = 200000 };
 	fd_set fds;
 
+	if (!can_wait)
+		return 0;
+
+	can_wait = 0;
+
 	FD_ZERO(&fds);
 	FD_SET(drmfd, &fds);
 	ret = select(drmfd + 1, &fds, NULL, NULL, &timeout);
@@ -159,18 +165,20 @@ static void do_pageflip(unsigned int offset)
 		return;
 	}
 
+	if (do_wait_vblank)
+		wait_vblank();
+
 	flip.fb_id = fb_id;
 	flip.crtc_id = crtc3d;
-	flip.flags = DRM_MODE_PAGE_FLIP_EVENT;
+	flip.flags = can_wait ? 0 : DRM_MODE_PAGE_FLIP_EVENT;
 	flip.reserved = 0;
 
 	ret = ioctl(drmfd, DRM_IOCTL_MODE_PAGE_FLIP, &flip);
 	if (ret) {
 		pr_err("page flip failed: %s\n", strerror(errno));
+		return;
 	}
-
-	if (do_wait_vblank)
-		wait_vblank();
+	can_wait = 1;
 }
 
 static void fbdev_ioctl(fuse_req_t req, int cmd, void *arg,
@@ -246,6 +254,7 @@ int bgi_init(struct kms_fb *fb, int crtc)
 
 	fb3d = fb;
 	crtc3d = crtc;
+	can_wait = 0;
 
 	fix.smem_start = fb->phys;
 	fix.smem_len = fb->pitch * fb->yres * 3;