[yocto] [meta-raspberrypi] gles2 on raspi3

[Andreas Müller]

On Sun, Apr 16, 2017 at 1:16 AM, Trevor Woerner <twoerner at gmail.com> wrote:
> w00T! \O/
>
> Swapping out meta-raspberrypi for your meta-raspi-light works!!! I now have
> accelerated glmark2-es2 ~40FPS :-D
>
> Now I have to figure out why...
>
> Also, chromium wouldn't build with meta-raspi2-light, but that's probably a
> quick fix, GL/glx.h was missing.
>
> Adding 'MACHINE_FEATURES_append = " vc4graphics"' to local.conf with
> meta-raspberrypi caused a kernel Oops. The system continues to run, but
> graphics/X doesn't work.
>
> One thing I've noticed about both meta-raspberrypi and meta-raspi-light are
> that in both cases (using vc4) the boot colour square (firmware?), processor
> core count berries, and kernel splash screen are missing. But that's not too
> important.
Yes - but I think this is not a bug. For me the so called 'rainbow'
screen was the indication I have VC4 properly set up.
>
> Thank you very much for your explanations, they really cleared up a lot of
> stuff in my head. Already I'm 10x smarter on this stuff (which doesn't say
> much about where I started!) ;-) It was probably a good thing I spent the last
> couple days grinding away, your explanations were perfect for where I'm at.
Some very good document explaining FOSS graphics stack is [1] - take
the time and some coffee :)
>
> Any idea how mesa and mesa-gl differ? That one's still an outlier for me; they
> both come from the same source base!
* userland builds egl/gles2 libraries
* mesa-gl is a drop in for (Desktop) OpenGL to ensure we can build
applications which need it. AFAIK it is shipped with swrast - so not
really useful.
>
> On Sat 2017-04-15 @ 08:09:02 PM, Andreas Müller wrote:
>> In the long run I would start a discussion:
>>
>> * Mesa/VC4 is not a machine feature only available on 64Bit Pi3 only:
>> It is common to all version of RaspberryPi. Using mesa should be a
>> decision easily selected by a setting somewhere. The only reason 64Bit
>> Pi3 gets VC4 by default is that userland is not working for 64Bit -
>> see commit 9d418db5ed2962821987ac90c07c3a61e40c0814)
>> * Why still use userland? Dropping it would make things MUCH easier:
>> All the decisions based vc4graphics in MACHINE_FEATURES could be
>> removed (that's what my fork does)
>
> Agreed! Maybe a new thread? I'd want to do more experiments wrt 32 vs 64 and
> vc4 vs userland before being able to contribute.
>
I cherry-pick from meta-raspberrypi what I can - also Pi3-64
configuration. But I have not run a test with 64Bit on Pi3 (I don't
expect any enhancements for my use cases).

Your next email:
> I got chromium building with it (it was a simple DEPENDS) and on the image I
> just built sound is already working!
* You have chromium building (and running?). This is on my endless
TODO-list (have firefox on my image but that crashes more or less
immediately - wonder what other people do with it)
* I have not tested that (I need low latency and plugs for playing music)

Have fun and keep me updated...

Andreas