Support for sharing serial interrupts

configname: CONFIG_SERIAL_8250_SHARE_IRQ

Linux Kernel Configuration
└─>Device Drivers
└─>Character devices
└─>Serial drivers
└─>Support for sharing serial interrupts
In linux kernel since version 2.6.20 (release Date: 2007-02-04)  
Some serial boards have hardware support which allows multiple dumb
serial ports on the same board to share a single IRQ. To enable
support for this in the serial driver, say Y here.