Index: Mk/Uses/kmod.mk
===================================================================
--- Mk/Uses/kmod.mk
+++ Mk/Uses/kmod.mk
@@ -4,8 +4,12 @@
 #
 # Feature:	kmod
 # Usage:	USES=kmod
-# Valid ARGS:	(none) debug
+# Valid ARGS:	(none), debug, minor
 #
+# debug		Build with debugging support
+# minor		Specify that the kmod must be built for each specific FreeBSD
+#		major.minor release per bsd.kmod-releases.mk
+#
 # MAINTAINER: rene@FreeBSD.org
 
 .if !defined(_INCLUDE_USES_KMOD_MK)
@@ -13,17 +17,45 @@
 
 _USES_POST+=	kmod
 
-.if empty(kmod_ARGS)
-_DEBUG_KMOD=
-.elif ${kmod_ARGS} == "debug"
+.if !empty(kmod_ARGS:Ndebug:Nminor)
+IGNORE=	USES=kmod has invalid arguments: ${kmod_ARGS:Ndebug:Nminor}
+.endif
+
+.if ${kmod_ARGS:Mdebug}
 _DEBUG_KMOD=	yes
 .else
-IGNORE=	USES=kmod takes either no arguments or 'debug'
+_DEBUG_KMOD=
 .endif
 
+FLAVORS=host
+# By default FLAVOR will have already been defined empty
+.if empty(FLAVOR)
+FLAVOR=host
+.endif
+
+.if ${kmod_ARGS:Mminor}
+
+.include "${PORTSDIR}/Mk/bsd.kmod-releases.mk"
+
+.for release in ${KMOD_RELEASES_${_OSVERSION_MAJOR}}
+.for flavor in ${release:C,\.([0-9])$,0\1,:S,.,,:S,^,fbsd,}
+_RELEASE_${flavor}=	${release}
+FLAVORS+=		${flavor}
+${flavor}_PKGNAMEPREFIX=	fbsd-${release}-
+${flavor}_BUILD_DEPENDS= \
+${LOCALBASE}/kernel-${release}/sys/Makefile:devel/freebsd-kernel-src@${flavor}
+.endfor
+.endfor
+
+.endif
+
+.if "${FLAVOR}" != "host"
+SRC_BASE=	${LOCALBASE}/kernel-${_RELEASE_${FLAVOR}}
+.else
 .if !exists(${SRC_BASE}/sys/Makefile)
 IGNORE=	requires kernel source files in SRC_BASE=${SRC_BASE}
 .endif
+.endif
 
 CATEGORIES+=	kld
 
Index: Mk/bsd.kmod-releases.mk
===================================================================
--- Mk/bsd.kmod-releases.mk
+++ Mk/bsd.kmod-releases.mk
@@ -0,0 +1,12 @@
+# $FreeBSD$
+#
+# List, for each major release, for which minor releases kernel module
+# flavors shall exist by default.
+
+.if !defined(_INCLUDE_BSD_KMOD_RELEASES_MK)
+_INCLUDE_BSD_KMOD_RELEASES_MK=       yes
+
+KMOD_RELEASES_11=	11.3
+KMOD_RELEASES_12=	12.1
+
+.endif
Index: devel/freebsd-kernel-src/Makefile
===================================================================
--- devel/freebsd-kernel-src/Makefile
+++ devel/freebsd-kernel-src/Makefile
@@ -0,0 +1,57 @@
+# $FreeBSD$
+
+PORTNAME=	freebsd-kernel-src
+PORTVERSION=	0
+CATEGORIES=	devel
+MASTER_SITES=	FREEBSD_ORG/releases/amd64/${OSRELEASE}
+DISTNAME=	src
+DIST_SUBDIR=	src-${OSRELEASE}
+# Note: This port fetches src.txz from amd64 regardless of ${ARCH}
+#       since source distribution does not differ between arches.
+
+MAINTAINER=	theron@FreeBSD.org
+COMMENT=	FreeBSD kernel sources for cross-building modules
+
+LICENSE=	BSD2CLAUSE
+
+FLAVORS=	${releases:C,\.([0-9])$,0\1,:S,.,,:S,^,fbsd,}
+FLAVOR?=	${default_OSVERSION_MAJMIN:C,\.([0-9])$,0\1,:S,.,,:S,^,fbsd,}
+
+USES=	tar:txz
+
+WRKSRC=	${WRKDIR}/usr/src
+
+.include <bsd.port.options.mk>
+.include "${PORTSDIR}/Mk/bsd.kmod-releases.mk"
+
+MAJOR_VERSIONS=	11 12
+
+OSVERSION_MAJOR=		${OSVERSION:C/([0-9]*[0-9])([0-9][0-9])[0-9]{3}/\1/}
+OSVERSION_MINOR=		${OSVERSION:C/([0-9]*[0-9])([0-9][0-9])[0-9]{3}/\2/:C/^0*//}
+default_OSVERSION_MAJMIN=	${OSVERSION_MAJOR}.${OSVERSION_MINOR}
+
+.for major in ${MAJOR_VERSIONS}
+releases+= ${KMOD_RELEASES_${major}}
+.endfor
+
+OSVERSION_MAJMIN?=	${${FLAVOR}_DISTVERSION}
+OSRELEASE=		${OSVERSION_MAJMIN}-RELEASE
+
+.for release in ${releases}
+flavor=${release:C,\.([0-9])$,0\1,:S,.,,:S,^,fbsd,}
+${flavor}_PKGNAMESUFFIX=-${release}
+${flavor}_DISTVERSION=${release}
+${flavor}_PLIST:=pkg-plist-${flavor}
+.endfor
+
+srcbase=	kernel-${OSVERSION_MAJMIN}
+
+run-autotools-fixup:
+do-configure:
+do-build:
+do-install:
+	${MKDIR} ${STAGEDIR}${PREFIX}/${srcbase}
+	${CP} -r ${WRKSRC}/sys ${STAGEDIR}${PREFIX}/${srcbase}/sys
+	${FIND} ${STAGEDIR}${PREFIX}/${srcbase} -type d -empty -delete
+
+.include <bsd.port.mk>
Index: devel/freebsd-kernel-src/distinfo
===================================================================
--- devel/freebsd-kernel-src/distinfo
+++ devel/freebsd-kernel-src/distinfo
@@ -0,0 +1,5 @@
+TIMESTAMP = 1583596347
+SHA256 (src-11.3-RELEASE/src.txz) = 534f1bdd14e751697fcff6fc87e91110f98bbdb3f63bc42782a10023cd766b3b
+SIZE (src-11.3-RELEASE/src.txz) = 158616472
+SHA256 (src-12.1-RELEASE/src.txz) = 98671007136c1f6e176411c061911b315fc59dd0af0690bff76dcba29767f6e6
+SIZE (src-12.1-RELEASE/src.txz) = 166199208
Index: devel/freebsd-kernel-src/makedistinfo.sh
===================================================================
--- devel/freebsd-kernel-src/makedistinfo.sh
+++ devel/freebsd-kernel-src/makedistinfo.sh
@@ -0,0 +1,31 @@
+#!/bin/sh
+
+releases="11.3 12.1"
+ftp="https://download.freebsd.org/ftp"
+DISTINFO_FILE=./distinfo
+
+echo "TIMESTAMP = $(date '+%s')" > ${DISTINFO_FILE}
+
+if [ ! -d "/usr/local/share/freebsd/MANIFESTS/" ]; then
+echo "This script requires misc/freebsd-release-manifests"
+exit 1
+fi
+
+for rel in ${releases}; do
+relname="${rel}-RELEASE"
+filename="src-${relname}/src.txz"
+echo Checking "${relname}"
+sha256=$(grep '^src\.txz	' /usr/local/share/freebsd/MANIFESTS/amd64-amd64-${relname} 2>&- | cut -f2)
+if [ -z "${sha256}" ]; then
+echo "Unknown release ${relname}"
+else
+hstat=$(curl -sI "${ftp}/releases/amd64/${relname}/src.txz" | tr -d '\r')
+if ( printf '%s' "${hstat}" | grep -q ' 404 ' ); then
+echo "Release ${relname} not present on server"
+else
+size=$(printf '%s' "${hstat}" | grep '^Content-Length: ' | cut -d' ' -f2)
+printf '%s (%s) = %s\n' "SHA256" "${filename}" "${sha256}" >> ${DISTINFO_FILE}
+printf '%s (%s) = %s\n' "SIZE" "${filename}" "${size}" >> ${DISTINFO_FILE}
+fi
+fi
+done
Index: devel/freebsd-kernel-src/pkg-descr
===================================================================
--- devel/freebsd-kernel-src/pkg-descr
+++ devel/freebsd-kernel-src/pkg-descr
@@ -0,0 +1,3 @@
+Installs FreeBSD kernel sources for cross-building of modules.
+
+WWW: https://www.freebsd.org/
Index: graphics/drm-fbsd12.0-kmod/Makefile
===================================================================
--- graphics/drm-fbsd12.0-kmod/Makefile
+++ graphics/drm-fbsd12.0-kmod/Makefile
@@ -23,7 +23,7 @@
 
 OPTIONS_DEFINE=	DEBUG
 
-USES=		kmod uidfix compiler:c++11-lang
+USES=		kmod:minor uidfix compiler:c++11-lang
 
 USE_GITHUB=	yes
 GH_ACCOUNT=	FreeBSDDesktop