sm501fb: fix timing limits

Vertical sync height register can only hold 6 bits.  Fix the hsync start test
to use > instead of >=.  Also add a few clarifying comments.

Signed-off-by: Ville Syrjala <[email protected]>
Acked-by: Ben Dooks <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

diff --git a/drivers/video/sm501fb.c b/drivers/video/sm501fb.c
index f49287c88abe2af349a45fc623bedf0100a4828a..742b5c656d668d447b02984d1fe4c2ba237c6743 100644 (file)
--- a/drivers/video/sm501fb.c
+++ b/drivers/video/sm501fb.c
@@ -237,12 +237,14 @@ static int sm501fb_check_var(struct fb_var_screeninfo *var,
 
        /* check we can fit these values into the registers */
 
-       if (var->hsync_len > 255 || var->vsync_len > 255)
+       if (var->hsync_len > 255 || var->vsync_len > 63)
                return -EINVAL;
 
-       if ((var->xres + var->right_margin) >= 4096)
+       /* hdisplay end and hsync start */
+       if ((var->xres + var->right_margin) > 4096)
                return -EINVAL;
 
+       /* vdisplay end and vsync start */
        if ((var->yres + var->lower_margin) > 2048)
                return -EINVAL;