cirrusfb: fix interlaced modes

Fix calculations of timings for interlaced modes.

Signed-off-by: Krzysztof Helt <krzysztof.h1@wp.pl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 21 insertions, 14 deletions

diff --git a/drivers/video/cirrusfb.c b/drivers/video/cirrusfb.c
index 9bb811d56721..d42e385f091c 100644
--- a/drivers/video/cirrusfb.c
+++ b/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) */