diff --git a/eclass/linux-mod.eclass b/eclass/linux-mod.eclass
index b3ea3e40f30f..096ded2839f4 100644
--- a/eclass/linux-mod.eclass
+++ b/eclass/linux-mod.eclass
@@ -22,6 +22,12 @@
 # A string containing the USE flag to use for making this eclass optional
 # The recommended non-empty value is 'modules'
 
+# @ECLASS-VARIABLE: MODULES_OPTIONAL_USE_IUSE_DEFAULT
+# @DESCRIPTION:
+# A boolean to control the IUSE default state for the MODULES_OPTIONAL_USE USE
+# flag. Default value is unset (false). True represented by 1 or 'on', other
+# values including unset treated as false.
+
 # @ECLASS-VARIABLE: KERNEL_DIR
 # @DESCRIPTION:
 # A string containing the directory of the target kernel sources. The default value is
@@ -129,7 +135,15 @@
 inherit eutils linux-info multilib
 EXPORT_FUNCTIONS pkg_setup pkg_preinst pkg_postinst src_install src_compile pkg_postrm
 
-IUSE="kernel_linux ${MODULES_OPTIONAL_USE}"
+case ${EAPI:-0} in
+	0) die "EAPI=${EAPI} is not supported due to lack of IUSE defaults" ;;
+esac
+
+case $MODULES_OPTIONAL_USE_IUSE_DEFAULT in
+	1) _modules_optional_use_iuse_default='+' ;;
+	*) _modules_optional_use_iuse_default='' ;;
+esac
+IUSE="kernel_linux ${_modules_optional_use_iuse_default}${MODULES_OPTIONAL_USE}"
 SLOT="0"
 RDEPEND="${MODULES_OPTIONAL_USE}${MODULES_OPTIONAL_USE:+? (} kernel_linux? ( virtual/modutils ) ${MODULES_OPTIONAL_USE:+)}"
 DEPEND="${RDEPEND}