CONFIG_X86_VISWS is not available for thedefaultarchitecture x86.
Result is shown for architecture i386

SGI 320/540 (Visual Workstation)

modulename: setup-irq.ko

configname: CONFIG_X86_VISWS

Subarchitecture Type
└─>SGI 320/540 (Visual Workstation)
In linux kernel since version 2.6.12  
The SGI Visual Workstation series is an IA32-based workstation
based on SGI systems chips with some legacy PC hardware attached.

Say Y here to create a kernel to run on the SGI 320 or 540.

A kernel compiled for the Visual Workstation will not run on PCs
and vice versa. See Documentation/sgi-visws.txt for details.

source code: