diff --git a/drivers/video/s3c-fb.c b/drivers/video/s3c-fb.c
index 43680e5..bb63c07 100644
--- a/drivers/video/s3c-fb.c
+++ b/drivers/video/s3c-fb.c
@@ -211,23 +211,21 @@ static int s3c_fb_check_var(struct fb_var_screeninfo *var,
 
 /**
  * s3c_fb_calc_pixclk() - calculate the divider to create the pixel clock.
+ * @id: window id.
  * @sfb: The hardware state.
  * @pixclock: The pixel clock wanted, in picoseconds.
  *
  * Given the specified pixel clock, work out the necessary divider to get
  * close to the output frequency.
  */
-static int s3c_fb_calc_pixclk(struct s3c_fb *sfb, unsigned int pixclk)
+static int s3c_fb_calc_pixclk(unsigned char id, struct s3c_fb *sfb, unsigned int pixclk)
 {
+	struct s3c_fb_pd_win *win = sfb->pdata->win[id];
 	unsigned long clk = clk_get_rate(sfb->bus_clk);
-	unsigned long long tmp;
 	unsigned int result;
 
-	tmp = (unsigned long long)clk;
-	tmp *= pixclk;
-
-	do_div(tmp, 1000000000UL);
-	result = (unsigned int)tmp / 1000;
+	pixclk *= win->win_mode.refresh;
+	result = clk / pixclk;
 
 	dev_dbg(sfb->dev, "pixclk=%u, clk=%lu, div=%d (%lu)\n",
 		pixclk, clk, result, clk / result);
@@ -267,6 +265,7 @@ static int s3c_fb_set_par(struct fb_info *info)
 	struct s3c_fb *sfb = win->parent;
 	void __iomem *regs = sfb->regs;
 	int win_no = win->index;
+	u32 osdc_data = 0;
 	u32 data;
 	u32 pagewidth;
 	int clkdiv;
@@ -302,7 +301,7 @@ static int s3c_fb_set_par(struct fb_info *info)
 	/* use window 0 as the basis for the lcd output timings */
 
 	if (win_no == 0) {
-		clkdiv = s3c_fb_calc_pixclk(sfb, var->pixclock);
+		clkdiv = s3c_fb_calc_pixclk(win_no, sfb, var->pixclock);
 
 		data = sfb->pdata->vidcon0;
 		data &= ~(VIDCON0_CLKVAL_F_MASK | VIDCON0_CLKDIR);
@@ -359,8 +358,6 @@ static int s3c_fb_set_par(struct fb_info *info)
 
 	data = var->xres * var->yres;
 
-	u32 osdc_data = 0;
-
 	osdc_data = VIDISD14C_ALPHA1_R(0xf) |
 		VIDISD14C_ALPHA1_G(0xf) |
 		VIDISD14C_ALPHA1_B(0xf);