diff --git a/drivers/gpu/drm/arm/hdlcd_crtc.c b/drivers/gpu/drm/arm/hdlcd_crtc.c
index cf5cbd6..d20e471 100644
--- a/drivers/gpu/drm/arm/hdlcd_crtc.c
+++ b/drivers/gpu/drm/arm/hdlcd_crtc.c
@@ -130,13 +130,7 @@ static void hdlcd_crtc_mode_set_nofb(struct drm_crtc *crtc)
 	struct videomode vm;
 	unsigned int polarities, err;
 
-	vm.vfront_porch = m->crtc_vsync_start - m->crtc_vdisplay;
-	vm.vback_porch = m->crtc_vtotal - m->crtc_vsync_end;
-	vm.vsync_len = m->crtc_vsync_end - m->crtc_vsync_start;
-	vm.hfront_porch = m->crtc_hsync_start - m->crtc_hdisplay;
-	vm.hback_porch = m->crtc_htotal - m->crtc_hsync_end;
-	vm.hsync_len = m->crtc_hsync_end - m->crtc_hsync_start;
-
+	drm_display_mode_crtc_to_videomode(m, &vm);
 	polarities = HDLCD_POLARITY_DATAEN | HDLCD_POLARITY_DATA;
 
 	if (m->flags & DRM_MODE_FLAG_PHSYNC)
diff --git a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_crtc.c b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_crtc.c
index d732810..bafcef6 100644
--- a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_crtc.c
+++ b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_crtc.c
@@ -81,12 +81,7 @@ static void atmel_hlcdc_crtc_mode_set_nofb(struct drm_crtc *c)
 	unsigned int cfg;
 	int div;
 
-	vm.vfront_porch = adj->crtc_vsync_start - adj->crtc_vdisplay;
-	vm.vback_porch = adj->crtc_vtotal - adj->crtc_vsync_end;
-	vm.vsync_len = adj->crtc_vsync_end - adj->crtc_vsync_start;
-	vm.hfront_porch = adj->crtc_hsync_start - adj->crtc_hdisplay;
-	vm.hback_porch = adj->crtc_htotal - adj->crtc_hsync_end;
-	vm.hsync_len = adj->crtc_hsync_end - adj->crtc_hsync_start;
+	drm_display_mode_crtc_to_videomode(adj, &vm);
 
 	regmap_write(regmap, ATMEL_HLCDC_CFG(1),
 		     (vm.hsync_len - 1) | ((vm.vsync_len - 1) << 16));
diff --git a/drivers/gpu/drm/drm_modes.c b/drivers/gpu/drm/drm_modes.c
index e82b61e..a406749 100644
--- a/drivers/gpu/drm/drm_modes.c
+++ b/drivers/gpu/drm/drm_modes.c
@@ -654,6 +654,26 @@ void drm_display_mode_to_videomode(const struct drm_display_mode *dmode,
 		vm->flags |= DISPLAY_FLAGS_DOUBLECLK;
 }
 EXPORT_SYMBOL_GPL(drm_display_mode_to_videomode);
+/**
+ * drm_display_mode_crtc_to_videomode - fill in @vm using crtc fields of@dmode,
+ * @dmode: drm_display_mode structure to use as source
+ * @vm: videomode structure to use as destination
+ *
+ * Fills out @vm using the crtc display mode specified in @dmode.
+ */
+void drm_display_mode_crtc_to_videomode(const struct drm_display_mode *dmode,
+				   struct videomode *vm)
+{
+	vm->hfront_porch = dmode->crtc_hsync_start - dmode->crtc_hdisplay;
+	vm->hsync_len = dmode->crtc_hsync_end - dmode->crtc_hsync_start;
+	vm->hback_porch = dmode->crtc_htotal - dmode->crtc_hsync_end;
+
+	vm->vfront_porch = dmode->crtc_vsync_start - dmode->crtc_vdisplay;
+	vm->vsync_len = dmode->crtc_vsync_end - dmode->crtc_vsync_start;
+	vm->vback_porch = dmode->crtc_vtotal - dmode->crtc_vsync_end;
+
+}
+EXPORT_SYMBOL_GPL(drm_display_mode_crtc_to_videomode);
 
 /**
  * drm_bus_flags_from_videomode - extract information about pixelclk and
diff --git a/drivers/gpu/drm/exynos/exynos5433_drm_decon.c b/drivers/gpu/drm/exynos/exynos5433_drm_decon.c
index 1c330f2..1ba73a8 100644
--- a/drivers/gpu/drm/exynos/exynos5433_drm_decon.c
+++ b/drivers/gpu/drm/exynos/exynos5433_drm_decon.c
@@ -20,6 +20,7 @@
 #include <linux/of_gpio.h>
 #include <linux/pm_runtime.h>
 #include <linux/regmap.h>
+#include <video/videomode.h>
 
 #include "exynos_drm_drv.h"
 #include "exynos_drm_crtc.h"
@@ -225,26 +226,23 @@ static void decon_commit(struct exynos_drm_crtc *crtc)
 	writel(val, ctx->addr + DECON_VIDTCON2);
 
 	if (!crtc->i80_mode) {
-		int vbp = m->crtc_vtotal - m->crtc_vsync_end;
-		int vfp = m->crtc_vsync_start - m->crtc_vdisplay;
+		struct videomode vm;
 
+		drm_display_mode_crtc_to_videomode(m, &vm);
 		if (interlaced)
-			vbp = vbp / 2 - 1;
-		val = VIDTCON00_VBPD_F(vbp - 1) | VIDTCON00_VFPD_F(vfp - 1);
+			vm.vback_porch = (vm.vback_porch >> 1) - 1;
+		val = VIDTCON00_VBPD_F(vm.vback_porch - 1) |
+			VIDTCON00_VFPD_F(vm.vfront_porch - 1);
 		writel(val, ctx->addr + DECON_VIDTCON00);
 
-		val = VIDTCON01_VSPW_F(
-				m->crtc_vsync_end - m->crtc_vsync_start - 1);
+		val = VIDTCON01_VSPW_F(vm.vsync_len - 1);
 		writel(val, ctx->addr + DECON_VIDTCON01);
 
-		val = VIDTCON10_HBPD_F(
-				m->crtc_htotal - m->crtc_hsync_end - 1) |
-			VIDTCON10_HFPD_F(
-				m->crtc_hsync_start - m->crtc_hdisplay - 1);
+		val = VIDTCON10_HBPD_F(vm.hback_porch - 1) |
+			VIDTCON10_HFPD_F(vm.hfront_porch - 1);
 		writel(val, ctx->addr + DECON_VIDTCON10);
 
-		val = VIDTCON11_HSPW_F(
-				m->crtc_hsync_end - m->crtc_hsync_start - 1);
+		val = VIDTCON11_HSPW_F(vm.hsync_len - 1);
 		writel(val, ctx->addr + DECON_VIDTCON11);
 	}
 
diff --git a/drivers/gpu/drm/exynos/exynos7_drm_decon.c b/drivers/gpu/drm/exynos/exynos7_drm_decon.c
index 3931d5e..148daae 100644
--- a/drivers/gpu/drm/exynos/exynos7_drm_decon.c
+++ b/drivers/gpu/drm/exynos/exynos7_drm_decon.c
@@ -25,6 +25,7 @@
 
 #include <video/of_display_timing.h>
 #include <video/of_videomode.h>
+#include <video/videomode.h>
 
 #include "exynos_drm_crtc.h"
 #include "exynos_drm_plane.h"
@@ -168,28 +169,24 @@ static void decon_commit(struct exynos_drm_crtc *crtc)
 		return;
 
 	if (!ctx->i80_if) {
-		int vsync_len, vbpd, vfpd, hsync_len, hbpd, hfpd;
+		struct videomode vm;
+
+		drm_display_mode_crtc_to_videomode(mode, &vm);
 	      /* setup vertical timing values. */
-		vsync_len = mode->crtc_vsync_end - mode->crtc_vsync_start;
-		vbpd = mode->crtc_vtotal - mode->crtc_vsync_end;
-		vfpd = mode->crtc_vsync_start - mode->crtc_vdisplay;
 
-		val = VIDTCON0_VBPD(vbpd - 1) | VIDTCON0_VFPD(vfpd - 1);
+		val = VIDTCON0_VBPD(vm.vback_porch - 1) |
+			VIDTCON0_VFPD(vm.vfront_porch - 1);
 		writel(val, ctx->regs + VIDTCON0);
 
-		val = VIDTCON1_VSPW(vsync_len - 1);
+		val = VIDTCON1_VSPW(vm.vsync_len - 1);
 		writel(val, ctx->regs + VIDTCON1);
 
 		/* setup horizontal timing values.  */
-		hsync_len = mode->crtc_hsync_end - mode->crtc_hsync_start;
-		hbpd = mode->crtc_htotal - mode->crtc_hsync_end;
-		hfpd = mode->crtc_hsync_start - mode->crtc_hdisplay;
-
-		/* setup horizontal timing values.  */
-		val = VIDTCON2_HBPD(hbpd - 1) | VIDTCON2_HFPD(hfpd - 1);
+		val = VIDTCON2_HBPD(vm.hback_porch - 1) |
+			VIDTCON2_HFPD(vm.hfront_porch - 1);
 		writel(val, ctx->regs + VIDTCON2);
 
-		val = VIDTCON3_HSPW(hsync_len - 1);
+		val = VIDTCON3_HSPW(vm.hsync_len - 1);
 		writel(val, ctx->regs + VIDTCON3);
 	}
 
diff --git a/drivers/gpu/drm/exynos/exynos_drm_fimd.c b/drivers/gpu/drm/exynos/exynos_drm_fimd.c
index d42ae2b..b3ab89d 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_fimd.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_fimd.c
@@ -25,6 +25,7 @@
 
 #include <video/of_display_timing.h>
 #include <video/of_videomode.h>
+#include <video/videomode.h>
 #include <video/samsung_fimd.h>
 #include <drm/exynos_drm.h>
 
@@ -463,7 +464,7 @@ static void fimd_commit(struct exynos_drm_crtc *crtc)
 			return;
 		}
 	} else {
-		int vsync_len, vbpd, vfpd, hsync_len, hbpd, hfpd;
+		struct videomode vm;
 		u32 vidcon1;
 
 		/* setup polarity values */
@@ -474,24 +475,19 @@ static void fimd_commit(struct exynos_drm_crtc *crtc)
 			vidcon1 |= VIDCON1_INV_HSYNC;
 		writel(vidcon1, ctx->regs + driver_data->timing_base + VIDCON1);
 
+		drm_display_mode_crtc_to_videomode(mode, &vm);
 		/* setup vertical timing values. */
-		vsync_len = mode->crtc_vsync_end - mode->crtc_vsync_start;
-		vbpd = mode->crtc_vtotal - mode->crtc_vsync_end;
-		vfpd = mode->crtc_vsync_start - mode->crtc_vdisplay;
 
-		val = VIDTCON0_VBPD(vbpd - 1) |
-			VIDTCON0_VFPD(vfpd - 1) |
-			VIDTCON0_VSPW(vsync_len - 1);
+		val = VIDTCON0_VBPD(vm.vback_porch - 1) |
+			VIDTCON0_VFPD(vm.vfront_porch - 1) |
+			VIDTCON0_VSPW(vm.vsync_len - 1);
 		writel(val, ctx->regs + driver_data->timing_base + VIDTCON0);
 
 		/* setup horizontal timing values.  */
-		hsync_len = mode->crtc_hsync_end - mode->crtc_hsync_start;
-		hbpd = mode->crtc_htotal - mode->crtc_hsync_end;
-		hfpd = mode->crtc_hsync_start - mode->crtc_hdisplay;
 
-		val = VIDTCON1_HBPD(hbpd - 1) |
-			VIDTCON1_HFPD(hfpd - 1) |
-			VIDTCON1_HSPW(hsync_len - 1);
+		val = VIDTCON1_HBPD(vm.hback_porch - 1) |
+			VIDTCON1_HFPD(vm.hfront_porch - 1) |
+			VIDTCON1_HSPW(vm.hsync_len - 1);
 		writel(val, ctx->regs + driver_data->timing_base + VIDTCON1);
 	}
 
diff --git a/include/drm/drm_modes.h b/include/drm/drm_modes.h
index 0d310be..9ac764b 100644
--- a/include/drm/drm_modes.h
+++ b/include/drm/drm_modes.h
@@ -473,6 +473,8 @@ void drm_display_mode_from_videomode(const struct videomode *vm,
 				     struct drm_display_mode *dmode);
 void drm_display_mode_to_videomode(const struct drm_display_mode *dmode,
 				   struct videomode *vm);
+void drm_display_mode_crtc_to_videomode(const struct drm_display_mode *dmode,
+				   struct videomode *vm);
 void drm_bus_flags_from_videomode(const struct videomode *vm, u32 *bus_flags);
 int of_get_drm_display_mode(struct device_node *np,
 			    struct drm_display_mode *dmode, u32 *bus_flags,
