[PATCH 5/6] drm/omap: Use old_fb to synchronize between successive page flips

[Archit Taneja <archit@ti.com>]

omap_crtc->old_fb is used to check whether the previous page flip has completed
or not. However, it's never initialized to anything, so it's always NULL. This
results in the check to always succeed, and the page_flip to proceed.

Initialize old_fb to the fb that we intend to flip to through page_flip, and
therefore prevent a future page flip to proceed if the last one didn't
complete.

Signed-off-by: Archit Taneja <archit@ti.com>
---
 drivers/gpu/drm/omapdrm/omap_crtc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/omapdrm/omap_crtc.c b/drivers/gpu/drm/omapdrm/omap_crtc.c
index 62f28df..d74c72c 100644
--- a/drivers/gpu/drm/omapdrm/omap_crtc.c
+++ b/drivers/gpu/drm/omapdrm/omap_crtc.c
@@ -360,7 +360,7 @@ static int omap_crtc_page_flip_locked(struct drm_crtc *crtc,
 	}
 
 	omap_crtc->event = event;
-	crtc->fb = fb;
+	omap_crtc->old_fb = crtc->fb = fb;
 
 	/*
 	 * Hold a reference temporarily until the crtc is updated
-- 
1.8.3.2