CONFIG_FB_DEFERRED_IO (not configurable)

modulename: fb_defio.ko

configname: CONFIG_FB_DEFERRED_IO

Linux Kernel Configuration
└─>Device Drivers
└─>Graphics support
└─>Support for frame buffer devices
└─>FB_DEFERRED_IO
In linux kernel since version 2.6.24 (release Date: 2008-01-24)  
source code:
drivers/video/fb_defio.c

is selected by
CONFIG_FB_METRONOME