int s1d13xxxfb_set_par (struct fb_info * info);
Using the fb_var_screeninfo in fb_info we set the depth of the framebuffer. This function alters the par AND the fb_fix_screeninfo stored in fb_info. It doesn't not alter var in fb_info since we are using that data. This means we depend on the data in var inside fb_info to be supported by the hardware. xxxfb_check_var is always called before xxxfb_set_par to ensure this.
write proper s1d13xxxfb_check_var, without which that function is quite useless.