[Mesa-dev] [RFC][PATCH 4/5] Android.mk: Add option to use vendor version of mesa

[Emil Velikov]

On 25 July 2018 at 20:52, John Stultz <john.stultz at linaro.org> wrote:
> On Wed, Jul 25, 2018 at 5:42 AM, Emil Velikov <emil.l.velikov at gmail.com> wrote:
>> On 25 July 2018 at 00:21, John Stultz <john.stultz at linaro.org> wrote:
>>> From: Yong Yao <yong.yao at intel.com>
>>>
>>> This is a forward port of a patch from the AOSP/master branch:
>>> https://android.googlesource.com/platform/external/mesa3d/+/b1e5fad1db4c1d51c7ae3a033b100a8429ae5415%5E%21/
>>>
>>> Which allows boards to provide their own custom copy of mesa.
>>>
>> Thanks for sorting these out John.
>>
>> My understanding was that when a custom project repo is used one
>> handles that in the device manifest. Roughly as:
>>  - foo.xml -> contains vast majority of the git repos with associated tags/etc
>>  - local.xml -> removes any repo/project from ^^, adds new one
>>
>> Is that no longer the case, or I simply misremember how Android does things?
>
> So, I'm not aware of the specific history behind this patch. And I
> can't speak for Google, there has been a general push via the Treble
> efforts to standardize the Android system image, and to push vendors
> to keep any device specific bits into their own device directory.  So
> there is a strong disincentive to modify projects in AOSP and in order
> to include things like devboards into AOSP, the push has been to limit
> any device specific changes to only the device directory git tree.
>
> So while one can technically still replace projects with local repos
> (and this is very useful for development!), I think they do not want
> folks doing this for shipping devices.
>
Hmm using the word "local" brought some assumptions that were never made.
AFAICT the remove/add project manifest combo can be used local
changes/testing as well as for "shipping devices".
Can it not?

> We are trying to make sure device support is pushed upstream to fdo,
> and then align AOSP's mesa to that, but one could imagine a board that
> doesn't have support upstream in mesa, and provides its own copy of
> mesa in the device directory. This patch allows the build to override
> the default mesa project with the vendor provided mesa.
>
Since the vendor will already need to add the project (git repo etc),
what is the blocker from removing the existing one beforehand?
Last I've tried - the repo tool gives you a nice and clear
warning/error message.

There is one case where this patch is a must. If repo forbids removing
"core" Android projects via the manifest.


Can anyone access the bug referenced in the gerrit commit?
Guess it could provide some clarity on the topic.

Thanks
Emil