[OE-core] what is MACHINE_HWCODECS used for these days?

[Mittal, Anuj]

On Fri, 2020-02-14 at 08:04 -0500, Robert P. J. Day wrote:
>   was documenting the use of [EXTRA_]IMAGE_FEATURES, and noticed that
> while the oe-core layer defines a related feature:
> 
>   core-image.bbclass:FEATURE_PACKAGES_hwcodecs =
> "${MACHINE_HWCODECS}"
>   core-image.bbclass:MACHINE_HWCODECS ??= ""

This ensures that packages in MACHINE_HWCODECS are installed in the
image if hwcodecs in included in IMAGE_FEATURES.

Thanks,

Anuj

> 
> i see no actual usage of that variable in oe-core (the git log goes
> way back to 2013:
> 
>   commit 1cb370587fd72e3f0f69678748108cc4116767fb
>   Author: Richard Purdie <richard.purdie at linuxfoundation.org>
>   Date:   Wed Jan 23 21:56:11 2013 -0800
> 
>     core-image: Add hwcodecs IMAGE_FEATURE
> 
>     Currently hardware codecs are being injected in rather ugly ways
> and end up
>     either in no or all images. This adds a dedicated IMAGE_FEATURE
> for them based
>     on the MACHINE_HWCODECS variable. We may need to refine this in
> due course
>     but this patch at least illustrates the concept.
> 
> i looked through other layers on my system, and found some references
> in meta-intel:
> 
> conf/machine/intel-core2-32.conf:MACHINE_HWCODECS ?= "intel-vaapi-
> driver gstreamer1.0-vaapi"
> conf/machine/intel-corei7-64.conf:MACHINE_HWCODECS ?= "
> ${@bb.utils.contains('TUNE_FEATURES', 'mx32', '', 'intel-media-driver
> intel-mediasdk', d)} intel-vaapi-driver gstreamer1.0-vaapi"
> conf/machine/intel-skylake-64.conf:MACHINE_HWCODECS ?= "intel-media-
> driver intel-mediasdk intel-vaapi-driver
> gstreamer1.0-vaapi"
> 
> but i see nothing in *that* layer that actually does anything with
> that variable after setting it. what is it used for? and how is it
> processed?
> 
> rday
>