From cbbb90b0c084d7dfb2ed8e3fecf8df200fbdd2a0 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
Git-commit: cbbb90b0c084d7dfb2ed8e3fecf8df200fbdd2a0
Patch-mainline: v4.14-rc1
References: bsc#1051510

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>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/gpu/drm/rcar-du/rcar_du_crtc.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/gpu/drm/rcar-du/rcar_du_crtc.c
+++ b/drivers/gpu/drm/rcar-du/rcar_du_crtc.c
@@ -698,7 +698,7 @@ static irqreturn_t rcar_du_crtc_irq(int
 	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);
 
 		if (rcdu->info->gen < 3)