default or selected kernelversion does not have config value CONFIG_BLK_DEV_SX8.
Result is shown for kernelversion 6.6-rc5

Promise SATA SX8 support

modulename: sx8.ko

configname: CONFIG_BLK_DEV_SX8

Linux Kernel Configuration
└─>Device Drivers
└─>Block devices
└─>Promise SATA SX8 support
In linux kernel since version 2.6.20 (release Date: 2007-02-04)  
Saying Y or M here will enable support for the
Promise SATA SX8 controllers.

Use devices /dev/sx8/$N and /dev/sx8/$Np$M.

source code: