CONFIG_TOSHIBA_RBTX4938_MPLEX_KEEP is not available for thedefaultarchitecture x86.
Result is shown for architecture mips

Keep firmware settings

configname: CONFIG_TOSHIBA_RBTX4938_MPLEX_KEEP

PIO[58:61]
└─>Keep firmware settings
In linux kernel since version 2.6.28 (release Date: 2008-12-24)