diff --git a/sys/alpha/conf/files.alpha b/sys/alpha/conf/files.alpha
index 39b2e9a7e9e6..13bb2c95ba77 100644
--- a/sys/alpha/conf/files.alpha
+++ b/sys/alpha/conf/files.alpha
@@ -152,6 +152,7 @@ isa/atkbd_isa.c			optional	atkbd
 isa/atkbdc_isa.c		optional	atkbdc
 isa/fd.c			optional	fd
 isa/psm.c			optional	psm
+isa/sio.c			optional	sio
 isa/syscons_isa.c		optional	sc
 isa/vga_isa.c			optional	vga
 kern/subr_diskmbr.c		standard
diff --git a/sys/conf/files.alpha b/sys/conf/files.alpha
index 39b2e9a7e9e6..13bb2c95ba77 100644
--- a/sys/conf/files.alpha
+++ b/sys/conf/files.alpha
@@ -152,6 +152,7 @@ isa/atkbd_isa.c			optional	atkbd
 isa/atkbdc_isa.c		optional	atkbdc
 isa/fd.c			optional	fd
 isa/psm.c			optional	psm
+isa/sio.c			optional	sio
 isa/syscons_isa.c		optional	sc
 isa/vga_isa.c			optional	vga
 kern/subr_diskmbr.c		standard
diff --git a/sys/conf/files.i386 b/sys/conf/files.i386
index add668ff424b..f288dd485af7 100644
--- a/sys/conf/files.i386
+++ b/sys/conf/files.i386
@@ -362,6 +362,7 @@ i4b/layer1/i4b_usr_sti.c	optional	isic
 isa/atkbd_isa.c			optional	atkbd
 isa/atkbdc_isa.c		optional	atkbdc
 isa/psm.c			optional	psm
+isa/sio.c			optional	sio
 isa/syscons_isa.c		optional	sc
 isa/vga_isa.c			optional	vga
 kern/subr_diskmbr.c		standard
diff --git a/sys/i386/conf/files.i386 b/sys/i386/conf/files.i386
index add668ff424b..f288dd485af7 100644
--- a/sys/i386/conf/files.i386
+++ b/sys/i386/conf/files.i386
@@ -362,6 +362,7 @@ i4b/layer1/i4b_usr_sti.c	optional	isic
 isa/atkbd_isa.c			optional	atkbd
 isa/atkbdc_isa.c		optional	atkbdc
 isa/psm.c			optional	psm
+isa/sio.c			optional	sio
 isa/syscons_isa.c		optional	sc
 isa/vga_isa.c			optional	vga
 kern/subr_diskmbr.c		standard