We must not use any information in the passed var besides xoffset,
yoffset and vmode as otherwise applications might abuse it.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
 
                        start   = fix->smem_start +
                                new_var.yoffset * fix->line_length +
-                               new_var.xoffset * var->bits_per_pixel / 8;
-                       end     = start + var->yres * fix->line_length - 1;
+                               new_var.xoffset * fbi->var.bits_per_pixel / 8;
+                       end     = start + fbi->var.yres * fix->line_length - 1;
                        par->dma_start  = start;
                        par->dma_end    = end;
                }