fake:

package/base/alsa-driver/alsa-driver.conf

@@ -22,8 +22,12 @@
 
 . $base/package/base/linux/kernelversion.sh
 
-confopt="$confopt --with-oss=yes --with-cards=all --with-sequencer=yes --with-isapnp=yes"
-confopt="$confopt --with-moddir=/lib/modules/$kernelversion/alsa"
+var_append confopt ' ' '--with-oss=yes --with-cards=all --with-sequencer=yes'
+var_append confopt ' ' "--with-isapnp=yes --with-moddir=/lib/modules/$kernelversion/alsa"
+
+[ "$arch" = "powerpc" ] && \
+	hook_add premake 1 "sed -i -e 's,\(CONFIG_SND_INTERWAVE.*\)=m,\1=n,' \
+		-e 's,CONFIG_SND_HDSPM=m,CONFIG_SND_HDSPM=n,' toplevel.config"
 
 # otherwise alsa installs other crap like an init scrpit ...
 makeinstopt="$makeopt install-modules install-headers"