Re: [gentoo-dev] RFC: Introducing VIDEO_CARDS=iris to virtual/opencl

[Marek Szuba <marecki@gentoo.org>]

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On 2019-12-17 21:21, Matt Turner wrote:

>> What do you think, guys?
> 
> I don't love it.
> 
> I don't like the mess that has become VIDEO_CARDS=... either. radeon
> vs radeonsi vs amdgpu.
[...]

I hear you and very much agree, especially regarding the Radeon mess.
That said, it seems what we are complaining about is the whole
VIDEO_CARDS system rather than the introduction of 'iris' into
virtual/opencl.

The current situation with OpenCL providers for Intel GPUs ugly even
disregarding the above. Basically, it is:

1. Set VIDEO_CARDS: i965

2a. If you do not set ABI_X86: 32 for virtual/opencl, it will pull in
dev-libs/intel-neo

2a.1. NEO may or may not work but with the former more likely than the
latter (it's been a few years since Broadwell architecture came out);

2b. If, however, you DO enable 32-bit x86 ABI it will pull
dev-libs/beignet instead

2b.1. Beignet at least for the time being is likely to work even on
modern systems but nowhere nearly as well as NEO would and without
official upstream support.


In contrast, reassigning NEO to video_cards_iris would make the
Intel-GPU provider tree much more straightforward:

1. For i965, you would get dev-libs/beignet regardless of whether you
want 32-bit x86 ABI or not;

2. For iris, you would get dev-libs/intel-neo for native 64 bits and
nothing (okay, technically it would fall back to media-libs/mesa - but
the fact Mesa is considered a fallback OpenCL provider for all GPUs is a
completely different can of worms) for 32-bit x86 ABI.


-- 
MS


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