diff --git a/sys/modules/sound/sound/Makefile b/sys/modules/sound/sound/Makefile
index 752fadd34478..8649d9653e27 100644
--- a/sys/modules/sound/sound/Makefile
+++ b/sys/modules/sound/sound/Makefile
@@ -4,14 +4,26 @@
 .PATH: ${.CURDIR}/../../../dev/sound/isa
 
 KMOD=	sound
-SRCS=	device_if.h bus_if.h isa_if.h pci_if.h
+SRCS=	device_if.h bus_if.h isa_if.h pci_if.h opt_isa.h
 SRCS+=	ac97_if.h channel_if.h feeder_if.h mixer_if.h
 SRCS+=	ac97_if.c channel_if.c feeder_if.c mixer_if.c
 SRCS+=	ac97.c ac97_patch.c buffer.c channel.c dsp.c
 SRCS+=	fake.c feeder.c feeder_fmt.c feeder_rate.c
 SRCS+=	mixer.c sndstat.c sound.c vchan.c
-SRCS+=	sndbuf_dma.c
 
 EXPORT_SYMS=	YES	# XXX evaluate
 
+.if ${MACHINE_ARCH} == "sparc64"
+# Create an empty opt_isa.h in order to keep kmod.mk from linking in an
+# existing one from KERNBUILDDIR which possibly has DEV_ISA defined so
+# sound.ko is always built without isadma support.
+opt_isa.h:
+	touch ${.TARGET}
+.else
+SRCS+=	sndbuf_dma.c
+
+opt_isa.h:
+	echo "#define DEV_ISA 1" > ${.TARGET}
+.endif
+
 .include <bsd.kmod.mk>