128 /** * Optinal callback for the dirty fb ioctl. * * Userspace can notify the driver via this callback * that a area of the framebuffer has changed and should * be flushed to the display hardware. * * See documentation in drm_mode.h for the struct * drm_mode_fb_dirty_cmd for more information as all * the semantics and arguments have a one to one mapping * on this function. */