unregister_framebuffer — releases a frame buffer device
| int unregister_framebuffer ( | struct fb_info * fb_info ); | 
   Unregisters a frame buffer device fb_info.
   
Returns negative errno on error, or zero for success.
This function will also notify the framebuffer console to release the driver.
   This is meant to be called within a driver's module_exit
   function. If this is called outside module_exit, ensure
   that the driver implements fb_open and fb_release to
   check that no processes are using the device.