diff --git a/sys/amd64/amd64/bios.c b/sys/amd64/amd64/bios.c
index 6eb90b2703d5..3d8f357ea19d 100644
--- a/sys/amd64/amd64/bios.c
+++ b/sys/amd64/amd64/bios.c
@@ -31,6 +31,8 @@
  * Code for dealing with the BIOS in x86 PC systems.
  */
 
+#include "opt_isa.h"
+
 #include <sys/param.h>
 #include <sys/systm.h>
 #include <sys/kernel.h>
@@ -44,9 +46,11 @@
 #include <machine/stdarg.h>
 #include <machine/vmparam.h>
 #include <machine/pc/bios.h>
+#ifdef DEV_ISA
 #include <isa/isavar.h>
 #include <isa/pnpreg.h>
 #include <isa/pnpvar.h>
+#endif
 
 #define BIOS_START	0xe0000
 #define BIOS_SIZE	0x20000
@@ -459,6 +463,7 @@ bios16(struct bios_args *args, char *fmt, ...)
     return (i);
 }
 
+#ifdef DEV_ISA
 /*
  * PnP BIOS interface; enumerate devices only known to the system
  * BIOS and save information about them for later use.
@@ -664,3 +669,4 @@ static driver_t pnpbios_driver = {
 static devclass_t pnpbios_devclass;
 
 DRIVER_MODULE(pnpbios, isa, pnpbios_driver, pnpbios_devclass, 0, 0);
+#endif /* DEV_ISA */
diff --git a/sys/amd64/amd64/fpu.c b/sys/amd64/amd64/fpu.c
index 5d44aaa2fab2..07bd2f58799b 100644
--- a/sys/amd64/amd64/fpu.c
+++ b/sys/amd64/amd64/fpu.c
@@ -37,6 +37,7 @@
 
 #include "opt_cpu.h"
 #include "opt_debug_npx.h"
+#include "opt_isa.h"
 #include "opt_math_emulate.h"
 #include "opt_npx.h"
 
@@ -83,7 +84,9 @@
 #endif
 #endif
 #include <i386/isa/intr_machdep.h>
+#ifdef DEV_ISA
 #include <isa/isavar.h>
+#endif
 
 /*
  * 387 and 287 Numeric Coprocessor Extension (NPX) Driver.
@@ -949,6 +952,7 @@ static driver_t npx_driver = {
 
 static devclass_t npx_devclass;
 
+#ifdef DEV_ISA
 /*
  * We prefer to attach to the root nexus so that the usual case (exception 16)
  * doesn't describe the processor as being `on isa'.
@@ -1003,4 +1007,4 @@ DRIVER_MODULE(npxisa, isa, npxisa_driver, npxisa_devclass, 0, 0);
 #ifndef PC98
 DRIVER_MODULE(npxisa, acpi, npxisa_driver, npxisa_devclass, 0, 0);
 #endif
-
+#endif /* DEV_ISA */
diff --git a/sys/amd64/amd64/legacy.c b/sys/amd64/amd64/legacy.c
index 2d7e8ca116a2..07518adf4f16 100644
--- a/sys/amd64/amd64/legacy.c
+++ b/sys/amd64/amd64/legacy.c
@@ -40,6 +40,8 @@
  * and I/O memory address space.
  */
 
+#include "opt_isa.h"
+
 #include <sys/param.h>
 #include <sys/systm.h>
 #include <sys/bus.h>
@@ -62,12 +64,14 @@
 #include <machine/mpapic.h>
 #endif
 
+#ifdef DEV_ISA
 #include <isa/isavar.h>
 #ifdef PC98
 #include <pc98/pc98/pc98.h>
 #else
 #include <i386/isa/isa.h>
 #endif
+#endif
 #include <i386/isa/icu.h>
 #include <i386/isa/intr_machdep.h>
 #include <sys/rtprio.h>
@@ -636,6 +640,7 @@ nexus_delete_resource(device_t dev, device_t child, int type, int rid)
 	resource_list_delete(rl, type, rid);
 }
 
+#ifdef DEV_ISA
 /*
  * Placeholder which claims PnP 'devices' which describe system 
  * resources.
@@ -683,3 +688,4 @@ static driver_t sysresource_driver = {
 static devclass_t sysresource_devclass;
 
 DRIVER_MODULE(sysresource, isa, sysresource_driver, sysresource_devclass, 0, 0);
+#endif /* DEV_ISA */
diff --git a/sys/amd64/amd64/nexus.c b/sys/amd64/amd64/nexus.c
index 2d7e8ca116a2..07518adf4f16 100644
--- a/sys/amd64/amd64/nexus.c
+++ b/sys/amd64/amd64/nexus.c
@@ -40,6 +40,8 @@
  * and I/O memory address space.
  */
 
+#include "opt_isa.h"
+
 #include <sys/param.h>
 #include <sys/systm.h>
 #include <sys/bus.h>
@@ -62,12 +64,14 @@
 #include <machine/mpapic.h>
 #endif
 
+#ifdef DEV_ISA
 #include <isa/isavar.h>
 #ifdef PC98
 #include <pc98/pc98/pc98.h>
 #else
 #include <i386/isa/isa.h>
 #endif
+#endif
 #include <i386/isa/icu.h>
 #include <i386/isa/intr_machdep.h>
 #include <sys/rtprio.h>
@@ -636,6 +640,7 @@ nexus_delete_resource(device_t dev, device_t child, int type, int rid)
 	resource_list_delete(rl, type, rid);
 }
 
+#ifdef DEV_ISA
 /*
  * Placeholder which claims PnP 'devices' which describe system 
  * resources.
@@ -683,3 +688,4 @@ static driver_t sysresource_driver = {
 static devclass_t sysresource_devclass;
 
 DRIVER_MODULE(sysresource, isa, sysresource_driver, sysresource_devclass, 0, 0);
+#endif /* DEV_ISA */
diff --git a/sys/amd64/amd64/tsc.c b/sys/amd64/amd64/tsc.c
index a39f7731be6a..ae5605117d10 100644
--- a/sys/amd64/amd64/tsc.c
+++ b/sys/amd64/amd64/tsc.c
@@ -49,6 +49,7 @@
  */
 
 #include "opt_clock.h"
+#include "opt_isa.h"
 #include "opt_mca.h"
 
 #include <sys/param.h>
@@ -83,7 +84,9 @@
 #include <i386/isa/icu.h>
 #include <i386/isa/isa.h>
 #include <isa/rtc.h>
+#ifdef DEV_ISA
 #include <isa/isavar.h>
+#endif
 #include <i386/isa/timerreg.h>
 
 #include <i386/isa/intr_machdep.h>
@@ -1260,6 +1263,7 @@ tsc_get_timecount(struct timecounter *tc)
 	return (rdtsc());
 }
 
+#ifdef DEV_ISA
 /*
  * Attach to the ISA PnP descriptors for the timer and realtime clock.
  */
@@ -1306,3 +1310,4 @@ static devclass_t attimer_devclass;
 
 DRIVER_MODULE(attimer, isa, attimer_driver, attimer_devclass, 0, 0);
 DRIVER_MODULE(attimer, acpi, attimer_driver, attimer_devclass, 0, 0);
+#endif /* DEV_ISA */
diff --git a/sys/amd64/isa/clock.c b/sys/amd64/isa/clock.c
index a39f7731be6a..ae5605117d10 100644
--- a/sys/amd64/isa/clock.c
+++ b/sys/amd64/isa/clock.c
@@ -49,6 +49,7 @@
  */
 
 #include "opt_clock.h"
+#include "opt_isa.h"
 #include "opt_mca.h"
 
 #include <sys/param.h>
@@ -83,7 +84,9 @@
 #include <i386/isa/icu.h>
 #include <i386/isa/isa.h>
 #include <isa/rtc.h>
+#ifdef DEV_ISA
 #include <isa/isavar.h>
+#endif
 #include <i386/isa/timerreg.h>
 
 #include <i386/isa/intr_machdep.h>
@@ -1260,6 +1263,7 @@ tsc_get_timecount(struct timecounter *tc)
 	return (rdtsc());
 }
 
+#ifdef DEV_ISA
 /*
  * Attach to the ISA PnP descriptors for the timer and realtime clock.
  */
@@ -1306,3 +1310,4 @@ static devclass_t attimer_devclass;
 
 DRIVER_MODULE(attimer, isa, attimer_driver, attimer_devclass, 0, 0);
 DRIVER_MODULE(attimer, acpi, attimer_driver, attimer_devclass, 0, 0);
+#endif /* DEV_ISA */
diff --git a/sys/amd64/isa/intr_machdep.c b/sys/amd64/isa/intr_machdep.c
index 3d20f9f7b5f0..98194a10e05a 100644
--- a/sys/amd64/isa/intr_machdep.c
+++ b/sys/amd64/isa/intr_machdep.c
@@ -148,6 +148,7 @@ static void	init_i8259(void);
 #define ENMI_IOSTATUS (1 << 5)
 #endif
 
+#ifdef DEV_ISA
 /*
  * Bus attachment for the ISA PIC.
  */
@@ -212,6 +213,7 @@ static devclass_t atpic_devclass;
 
 DRIVER_MODULE(atpic, isa, atpic_driver, atpic_devclass, 0, 0);
 DRIVER_MODULE(atpic, acpi, atpic_driver, atpic_devclass, 0, 0);
+#endif /* DEV_ISA */
 
 /*
  * Handle a NMI, possibly a machine check.
diff --git a/sys/amd64/isa/nmi.c b/sys/amd64/isa/nmi.c
index 3d20f9f7b5f0..98194a10e05a 100644
--- a/sys/amd64/isa/nmi.c
+++ b/sys/amd64/isa/nmi.c
@@ -148,6 +148,7 @@ static void	init_i8259(void);
 #define ENMI_IOSTATUS (1 << 5)
 #endif
 
+#ifdef DEV_ISA
 /*
  * Bus attachment for the ISA PIC.
  */
@@ -212,6 +213,7 @@ static devclass_t atpic_devclass;
 
 DRIVER_MODULE(atpic, isa, atpic_driver, atpic_devclass, 0, 0);
 DRIVER_MODULE(atpic, acpi, atpic_driver, atpic_devclass, 0, 0);
+#endif /* DEV_ISA */
 
 /*
  * Handle a NMI, possibly a machine check.
diff --git a/sys/amd64/isa/npx.c b/sys/amd64/isa/npx.c
index 5d44aaa2fab2..07bd2f58799b 100644
--- a/sys/amd64/isa/npx.c
+++ b/sys/amd64/isa/npx.c
@@ -37,6 +37,7 @@
 
 #include "opt_cpu.h"
 #include "opt_debug_npx.h"
+#include "opt_isa.h"
 #include "opt_math_emulate.h"
 #include "opt_npx.h"
 
@@ -83,7 +84,9 @@
 #endif
 #endif
 #include <i386/isa/intr_machdep.h>
+#ifdef DEV_ISA
 #include <isa/isavar.h>
+#endif
 
 /*
  * 387 and 287 Numeric Coprocessor Extension (NPX) Driver.
@@ -949,6 +952,7 @@ static driver_t npx_driver = {
 
 static devclass_t npx_devclass;
 
+#ifdef DEV_ISA
 /*
  * We prefer to attach to the root nexus so that the usual case (exception 16)
  * doesn't describe the processor as being `on isa'.
@@ -1003,4 +1007,4 @@ DRIVER_MODULE(npxisa, isa, npxisa_driver, npxisa_devclass, 0, 0);
 #ifndef PC98
 DRIVER_MODULE(npxisa, acpi, npxisa_driver, npxisa_devclass, 0, 0);
 #endif
-
+#endif /* DEV_ISA */
diff --git a/sys/i386/i386/bios.c b/sys/i386/i386/bios.c
index 6eb90b2703d5..3d8f357ea19d 100644
--- a/sys/i386/i386/bios.c
+++ b/sys/i386/i386/bios.c
@@ -31,6 +31,8 @@
  * Code for dealing with the BIOS in x86 PC systems.
  */
 
+#include "opt_isa.h"
+
 #include <sys/param.h>
 #include <sys/systm.h>
 #include <sys/kernel.h>
@@ -44,9 +46,11 @@
 #include <machine/stdarg.h>
 #include <machine/vmparam.h>
 #include <machine/pc/bios.h>
+#ifdef DEV_ISA
 #include <isa/isavar.h>
 #include <isa/pnpreg.h>
 #include <isa/pnpvar.h>
+#endif
 
 #define BIOS_START	0xe0000
 #define BIOS_SIZE	0x20000
@@ -459,6 +463,7 @@ bios16(struct bios_args *args, char *fmt, ...)
     return (i);
 }
 
+#ifdef DEV_ISA
 /*
  * PnP BIOS interface; enumerate devices only known to the system
  * BIOS and save information about them for later use.
@@ -664,3 +669,4 @@ static driver_t pnpbios_driver = {
 static devclass_t pnpbios_devclass;
 
 DRIVER_MODULE(pnpbios, isa, pnpbios_driver, pnpbios_devclass, 0, 0);
+#endif /* DEV_ISA */
diff --git a/sys/i386/i386/legacy.c b/sys/i386/i386/legacy.c
index 2d7e8ca116a2..07518adf4f16 100644
--- a/sys/i386/i386/legacy.c
+++ b/sys/i386/i386/legacy.c
@@ -40,6 +40,8 @@
  * and I/O memory address space.
  */
 
+#include "opt_isa.h"
+
 #include <sys/param.h>
 #include <sys/systm.h>
 #include <sys/bus.h>
@@ -62,12 +64,14 @@
 #include <machine/mpapic.h>
 #endif
 
+#ifdef DEV_ISA
 #include <isa/isavar.h>
 #ifdef PC98
 #include <pc98/pc98/pc98.h>
 #else
 #include <i386/isa/isa.h>
 #endif
+#endif
 #include <i386/isa/icu.h>
 #include <i386/isa/intr_machdep.h>
 #include <sys/rtprio.h>
@@ -636,6 +640,7 @@ nexus_delete_resource(device_t dev, device_t child, int type, int rid)
 	resource_list_delete(rl, type, rid);
 }
 
+#ifdef DEV_ISA
 /*
  * Placeholder which claims PnP 'devices' which describe system 
  * resources.
@@ -683,3 +688,4 @@ static driver_t sysresource_driver = {
 static devclass_t sysresource_devclass;
 
 DRIVER_MODULE(sysresource, isa, sysresource_driver, sysresource_devclass, 0, 0);
+#endif /* DEV_ISA */
diff --git a/sys/i386/i386/nexus.c b/sys/i386/i386/nexus.c
index 2d7e8ca116a2..07518adf4f16 100644
--- a/sys/i386/i386/nexus.c
+++ b/sys/i386/i386/nexus.c
@@ -40,6 +40,8 @@
  * and I/O memory address space.
  */
 
+#include "opt_isa.h"
+
 #include <sys/param.h>
 #include <sys/systm.h>
 #include <sys/bus.h>
@@ -62,12 +64,14 @@
 #include <machine/mpapic.h>
 #endif
 
+#ifdef DEV_ISA
 #include <isa/isavar.h>
 #ifdef PC98
 #include <pc98/pc98/pc98.h>
 #else
 #include <i386/isa/isa.h>
 #endif
+#endif
 #include <i386/isa/icu.h>
 #include <i386/isa/intr_machdep.h>
 #include <sys/rtprio.h>
@@ -636,6 +640,7 @@ nexus_delete_resource(device_t dev, device_t child, int type, int rid)
 	resource_list_delete(rl, type, rid);
 }
 
+#ifdef DEV_ISA
 /*
  * Placeholder which claims PnP 'devices' which describe system 
  * resources.
@@ -683,3 +688,4 @@ static driver_t sysresource_driver = {
 static devclass_t sysresource_devclass;
 
 DRIVER_MODULE(sysresource, isa, sysresource_driver, sysresource_devclass, 0, 0);
+#endif /* DEV_ISA */
diff --git a/sys/i386/i386/tsc.c b/sys/i386/i386/tsc.c
index a39f7731be6a..ae5605117d10 100644
--- a/sys/i386/i386/tsc.c
+++ b/sys/i386/i386/tsc.c
@@ -49,6 +49,7 @@
  */
 
 #include "opt_clock.h"
+#include "opt_isa.h"
 #include "opt_mca.h"
 
 #include <sys/param.h>
@@ -83,7 +84,9 @@
 #include <i386/isa/icu.h>
 #include <i386/isa/isa.h>
 #include <isa/rtc.h>
+#ifdef DEV_ISA
 #include <isa/isavar.h>
+#endif
 #include <i386/isa/timerreg.h>
 
 #include <i386/isa/intr_machdep.h>
@@ -1260,6 +1263,7 @@ tsc_get_timecount(struct timecounter *tc)
 	return (rdtsc());
 }
 
+#ifdef DEV_ISA
 /*
  * Attach to the ISA PnP descriptors for the timer and realtime clock.
  */
@@ -1306,3 +1310,4 @@ static devclass_t attimer_devclass;
 
 DRIVER_MODULE(attimer, isa, attimer_driver, attimer_devclass, 0, 0);
 DRIVER_MODULE(attimer, acpi, attimer_driver, attimer_devclass, 0, 0);
+#endif /* DEV_ISA */
diff --git a/sys/i386/isa/clock.c b/sys/i386/isa/clock.c
index a39f7731be6a..ae5605117d10 100644
--- a/sys/i386/isa/clock.c
+++ b/sys/i386/isa/clock.c
@@ -49,6 +49,7 @@
  */
 
 #include "opt_clock.h"
+#include "opt_isa.h"
 #include "opt_mca.h"
 
 #include <sys/param.h>
@@ -83,7 +84,9 @@
 #include <i386/isa/icu.h>
 #include <i386/isa/isa.h>
 #include <isa/rtc.h>
+#ifdef DEV_ISA
 #include <isa/isavar.h>
+#endif
 #include <i386/isa/timerreg.h>
 
 #include <i386/isa/intr_machdep.h>
@@ -1260,6 +1263,7 @@ tsc_get_timecount(struct timecounter *tc)
 	return (rdtsc());
 }
 
+#ifdef DEV_ISA
 /*
  * Attach to the ISA PnP descriptors for the timer and realtime clock.
  */
@@ -1306,3 +1310,4 @@ static devclass_t attimer_devclass;
 
 DRIVER_MODULE(attimer, isa, attimer_driver, attimer_devclass, 0, 0);
 DRIVER_MODULE(attimer, acpi, attimer_driver, attimer_devclass, 0, 0);
+#endif /* DEV_ISA */
diff --git a/sys/i386/isa/intr_machdep.c b/sys/i386/isa/intr_machdep.c
index 3d20f9f7b5f0..98194a10e05a 100644
--- a/sys/i386/isa/intr_machdep.c
+++ b/sys/i386/isa/intr_machdep.c
@@ -148,6 +148,7 @@ static void	init_i8259(void);
 #define ENMI_IOSTATUS (1 << 5)
 #endif
 
+#ifdef DEV_ISA
 /*
  * Bus attachment for the ISA PIC.
  */
@@ -212,6 +213,7 @@ static devclass_t atpic_devclass;
 
 DRIVER_MODULE(atpic, isa, atpic_driver, atpic_devclass, 0, 0);
 DRIVER_MODULE(atpic, acpi, atpic_driver, atpic_devclass, 0, 0);
+#endif /* DEV_ISA */
 
 /*
  * Handle a NMI, possibly a machine check.
diff --git a/sys/i386/isa/nmi.c b/sys/i386/isa/nmi.c
index 3d20f9f7b5f0..98194a10e05a 100644
--- a/sys/i386/isa/nmi.c
+++ b/sys/i386/isa/nmi.c
@@ -148,6 +148,7 @@ static void	init_i8259(void);
 #define ENMI_IOSTATUS (1 << 5)
 #endif
 
+#ifdef DEV_ISA
 /*
  * Bus attachment for the ISA PIC.
  */
@@ -212,6 +213,7 @@ static devclass_t atpic_devclass;
 
 DRIVER_MODULE(atpic, isa, atpic_driver, atpic_devclass, 0, 0);
 DRIVER_MODULE(atpic, acpi, atpic_driver, atpic_devclass, 0, 0);
+#endif /* DEV_ISA */
 
 /*
  * Handle a NMI, possibly a machine check.
diff --git a/sys/i386/isa/npx.c b/sys/i386/isa/npx.c
index 5d44aaa2fab2..07bd2f58799b 100644
--- a/sys/i386/isa/npx.c
+++ b/sys/i386/isa/npx.c
@@ -37,6 +37,7 @@
 
 #include "opt_cpu.h"
 #include "opt_debug_npx.h"
+#include "opt_isa.h"
 #include "opt_math_emulate.h"
 #include "opt_npx.h"
 
@@ -83,7 +84,9 @@
 #endif
 #endif
 #include <i386/isa/intr_machdep.h>
+#ifdef DEV_ISA
 #include <isa/isavar.h>
+#endif
 
 /*
  * 387 and 287 Numeric Coprocessor Extension (NPX) Driver.
@@ -949,6 +952,7 @@ static driver_t npx_driver = {
 
 static devclass_t npx_devclass;
 
+#ifdef DEV_ISA
 /*
  * We prefer to attach to the root nexus so that the usual case (exception 16)
  * doesn't describe the processor as being `on isa'.
@@ -1003,4 +1007,4 @@ DRIVER_MODULE(npxisa, isa, npxisa_driver, npxisa_devclass, 0, 0);
 #ifndef PC98
 DRIVER_MODULE(npxisa, acpi, npxisa_driver, npxisa_devclass, 0, 0);
 #endif
-
+#endif /* DEV_ISA */
diff --git a/sys/isa/atrtc.c b/sys/isa/atrtc.c
index a39f7731be6a..ae5605117d10 100644
--- a/sys/isa/atrtc.c
+++ b/sys/isa/atrtc.c
@@ -49,6 +49,7 @@
  */
 
 #include "opt_clock.h"
+#include "opt_isa.h"
 #include "opt_mca.h"
 
 #include <sys/param.h>
@@ -83,7 +84,9 @@
 #include <i386/isa/icu.h>
 #include <i386/isa/isa.h>
 #include <isa/rtc.h>
+#ifdef DEV_ISA
 #include <isa/isavar.h>
+#endif
 #include <i386/isa/timerreg.h>
 
 #include <i386/isa/intr_machdep.h>
@@ -1260,6 +1263,7 @@ tsc_get_timecount(struct timecounter *tc)
 	return (rdtsc());
 }
 
+#ifdef DEV_ISA
 /*
  * Attach to the ISA PnP descriptors for the timer and realtime clock.
  */
@@ -1306,3 +1310,4 @@ static devclass_t attimer_devclass;
 
 DRIVER_MODULE(attimer, isa, attimer_driver, attimer_devclass, 0, 0);
 DRIVER_MODULE(attimer, acpi, attimer_driver, attimer_devclass, 0, 0);
+#endif /* DEV_ISA */