From 2764083d283ec60a63a00519bae85be93067ce1a Mon Sep 17 00:00:00 2001
From: Huaibin Yang <huaibiny@codeaurora.org>
Date: Tue, 4 Sep 2012 13:31:29 -0700
Subject: [PATCH] msm_fb: display: fix division-by-zero bug

Panel v_back_porch could be zero for virtual panels, so the check for
zero is added to fix the bug.

Change-Id: I6a29f3d8d771092bca2374cc9a1c11dd77ad569e
Signed-off-by: Huaibin Yang <huaibiny@codeaurora.org>
---
 drivers/video/msm/mdp4_overlay.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/video/msm/mdp4_overlay.c b/drivers/video/msm/mdp4_overlay.c
index 11eaa9f13d61..d338946b4be1 100644
--- a/drivers/video/msm/mdp4_overlay.c
+++ b/drivers/video/msm/mdp4_overlay.c
@@ -2616,7 +2616,8 @@ static int mdp4_calc_pipe_mdp_clk(struct msm_fb_data_type *mfd,
 	 * required(FIR).
 	 */
 	if ((mfd->panel_info.lcdc.v_back_porch <= 4) &&
-	    (pipe->src_h != pipe->dst_h)) {
+	    (pipe->src_h != pipe->dst_h) &&
+	    (mfd->panel_info.lcdc.v_back_porch)) {
 		u32 clk = 0;
 		clk = 4 * (pclk >> shift) / mfd->panel_info.lcdc.v_back_porch;
 		clk <<= shift;