[meta-ti] Trouble modifying defconfig for linux-ti-staging_rt recipe

[Glenn Schmottlach]

I am having trouble modifying the kernel configuration for the
following TI kernel recipe using the Yocto Morty environment:

linux-ti-staging-rt_4.9.bb

I have created my own layer and with a *.bbappend file for this recipe, e.g.

linux-ti-staging-rt_4.9.bbappend

It appears the TI kernel recipes are not (yet) proper "Yocto" kernel
recipes in that they are not "fragment" aware. It appears I cannot do
the following inside of my *.bbappend recipe:

FILESEXTRAPATHS_prepend := "${THISDIR}/${PN}:"
SRC_URI += "file://eem.cfg"

Inside of "eem.cfg" I want to set the following kernel options:

CONFIG_USB_NET_CDC_EEM=m
CONFIG_USB_F_EEM=m
CONFIG_USB_ETH_EEM=y

This has no affect. I tried creating my own defconfig based on the
'.config' generated from the original recipe. I modified my *.bbappend
file as follows:

FILESEXTRAPATHS_prepend := "${THISDIR}/${PN}:"
SRC_URI += "file://defconfig"

Again, my defconfig is not applied to the build.

I even tried patching kernel-source/ti_config_fragments and placing a
eem.cfg in that directory hoping the configuration generation script
(defconfig_builder.sh) might apply this fragment.

FILESEXTRAPATHS_prepend := "${THISDIR}/${PN}:"
SRC_URI += "file://0001-eem-config.patch"

Where the patch contains:

Index: kernel-source/ti_config_fragments/eem.cfg
===================================================================
--- /dev/null
+++ kernel-source/ti_config_fragments/eem.cfg
@@ -0,0 +1,4 @@
+CONFIG_USB_NET_CDC_EEM=m
+CONFIG_USB_F_EEM=m
+CONFIG_USB_ETH_EEM=y
+

Unfortunately this did not work either.

I suspect this question has been asked before, but what is the
RECOMMENDED procedure for making kernel configuration changes to the
TI kernel recipes in a Yocto environment? What methods have others
used to tweak the TI kernel options from their *.bbappend files?

Thanks for any insights . . .