From 758e22acf4fd9aaf51c7bae93a47401b8f792d56 Mon Sep 17 00:00:00 2001
From: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Date: Mon, 10 Jul 2017 23:46:39 +0300
Subject: [PATCH] drm: rcar-du: Use the VBK interrupt for vblank events

commit cbbb90b0c084d7dfb2ed8e3fecf8df200fbdd2a0 upstream.

When implementing support for interlaced modes, the driver switched from
reporting vblank events on the vertical blanking (VBK) interrupt to the
frame end interrupt (FRM). This incorrectly divided the reported refresh
rate by two. Fix it by moving back to the VBK interrupt.

Fixes: 906eff7fcada ("drm: rcar-du: Implement support for interlaced modes")
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Signed-off-by: thongsyho <thong.ho.px@rvc.renesas.com>
Signed-off-by: Nhan Nguyen <nhan.nguyen.yb@renesas.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/gpu/drm/rcar-du/rcar_du_crtc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/rcar-du/rcar_du_crtc.c b/drivers/gpu/drm/rcar-du/rcar_du_crtc.c
index a2ec6d8796a09..848f7f2152eed 100644
--- a/drivers/gpu/drm/rcar-du/rcar_du_crtc.c
+++ b/drivers/gpu/drm/rcar-du/rcar_du_crtc.c
@@ -551,7 +551,7 @@ static irqreturn_t rcar_du_crtc_irq(int irq, void *arg)
 	status = rcar_du_crtc_read(rcrtc, DSSR);
 	rcar_du_crtc_write(rcrtc, DSRCR, status & DSRCR_MASK);
 
-	if (status & DSSR_FRM) {
+	if (status & DSSR_VBK) {
 		drm_crtc_handle_vblank(&rcrtc->crtc);
 		rcar_du_crtc_finish_page_flip(rcrtc);
 		ret = IRQ_HANDLED;