CONFIG_V4L2_ASYNC (not configurable)

modulename: v4l2-async.ko

configname: CONFIG_V4L2_ASYNC

Linux Kernel Configuration
└─>Device Drivers
└─>Multimedia support
└─>Video4Linux options
└─>V4L2_ASYNC
In linux kernel since version 4.14.326 (release Date: 2023-09-23)  
source code:
drivers/media/v4l2-core/v4l2-async.c