emenlow: add LICENSE_FLAG_WHITELIST information to README

The switchover to emgd neglected to add the user documentation needed
for whitelisting the video components.  This adds it and now matches
the other emgd-based BSPs.

Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>

1 files changed, 27 insertions, 4 deletions

diff --git a/meta-emenlow/README b/meta-emenlow/README
index 6cc06fe6..9487ff8c 100644
--- a/meta-emenlow/README
+++ b/meta-emenlow/README
@@ -82,11 +82,14 @@ common metadata shared between BSPs) e.g.:
   yocto/meta-intel \
   yocto/meta-intel/meta-emenlow \
 
-The meta-emenlow layer contains support for the 'emenlow' machine
-configuration, which makes use of the Intel-proprietary EMGD 1.16
-graphics driver.
+The meta-emenlow layer contains support for two different machine
+configurations. These configurations are identical except for the fact
+that the one prefixed with 'emenlow' makes use of the
+Intel-proprietary EMGD 1.16 graphics driver, while the one prefixed
+with 'emenlow-noemgd' does not.
 
-To enable the emenlow layer, add the emenlow MACHINE to local.conf:
+If you want to enable the layer that supports EMGD graphics add the
+following to the local.conf file:
 
   MACHINE ?= "emenlow"
 
@@ -97,6 +100,11 @@ in your local.conf.  For example:
 
   LICENSE_FLAGS_WHITELIST = "license_emgd-driver-bin_1.16"
 
+If you want to enable the layer that does not support EMGD graphics
+add the following to the local.conf file:
+
+  MACHINE ?= "emenlow-noemgd"
+
 You should then be able to build an emenlow image as such:
 
   $ source oe-init-build-env
@@ -106,6 +114,21 @@ At the end of a successful build, you should have a live image that
 you can boot from a USB flash drive (see instructions on how to do
 that below, in the section 'Booting the images from /binary').
 
+NOTE: The 'emenlow' machine will include support for hardware video
+acceleration via gstreamer if and only if the "commercial" string is
+added to the the LICENSE_FLAGS_WHITELIST variable in your local.conf.
+
+For example:
+
+  LICENSE_FLAGS_WHITELIST = "license_emgd-driver-bin_1.16 commercial"
+
+The reason this is needed is to prevent the image from including
+anything that might violate the license terms of the packages used to
+implement the the video acceleration feature, such as gst-ffmpeg and
+ffmpeg.  As always, please consult the licenses included in the
+specific packages for details if you use packages that require
+particular LICENSE_FLAGS.
+
 As an alternative to downloading the BSP tarball, you can also work
 directly from the meta-intel git repository.  For each BSP in the
 'meta-intel' repository, there are multiple branches, one