cirrusfb: fix interlaced modes

Fix calculations of timings for interlaced modes.
Signed-off-by: NKrzysztof Helt <krzysztof.h1@wp.pl>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

drivers/video/cirrusfb.c

@@ -701,45 +701,52 @@ static int cirrusfb_set_par_foo(struct fb_info *info)
 
 	hsyncstart = var->xres + var->right_margin;
 	hsyncend = hsyncstart + var->hsync_len;
-	htotal = (hsyncend + var->left_margin) / 8 - 5;
-	hdispend = var->xres / 8 - 1;
-	hsyncstart = hsyncstart / 8 + 1;
-	hsyncend = hsyncend / 8 + 1;
+	htotal = (hsyncend + var->left_margin) / 8;
+	hdispend = var->xres / 8;
+	hsyncstart = hsyncstart / 8;
+	hsyncend = hsyncend / 8;
 
-	yres = var->yres;
-	vsyncstart = yres + var->lower_margin;
+	vdispend = var->yres;
+	vsyncstart = vdispend + var->lower_margin;
 	vsyncend = vsyncstart + var->vsync_len;
 	vtotal = vsyncend + var->upper_margin;
-	vdispend = yres - 1;
 
 	if (var->vmode & FB_VMODE_DOUBLE) {
-		yres *= 2;
+		vdispend *= 2;
 		vsyncstart *= 2;
 		vsyncend *= 2;
 		vtotal *= 2;
 	} else if (var->vmode & FB_VMODE_INTERLACED) {
-		yres = (yres + 1) / 2;
+		vdispend = (vdispend + 1) / 2;
 		vsyncstart = (vsyncstart + 1) / 2;
 		vsyncend = (vsyncend + 1) / 2;
 		vtotal = (vtotal + 1) / 2;
 	}
-
-	vtotal -= 2;
-	vsyncstart -= 1;
-	vsyncend -= 1;
-
+	yres = vdispend;
 	if (yres >= 1024) {
 		vtotal /= 2;
 		vsyncstart /= 2;
 		vsyncend /= 2;
 		vdispend /= 2;
 	}
+
+	vdispend -= 1;
+	vsyncstart -= 1;
+	vsyncend -= 1;
+	vtotal -= 2;
+
 	if (cinfo->multiplexing) {
 		htotal /= 2;
 		hsyncstart /= 2;
 		hsyncend /= 2;
 		hdispend /= 2;
 	}
+
+	htotal -= 5;
+	hdispend -= 1;
+	hsyncstart += 1;
+	hsyncend += 1;
+
 	/* unlock register VGA_CRTC_H_TOTAL..CRT7 */
 	vga_wcrt(regbase, VGA_CRTC_V_SYNC_END, 0x20);	/* previously: 0x00) */