[Mesa-dev] GBM backend dynamic dispatch method

[Nicolai Hähnle]

On 12.05.2016 20:20, Jammy Zhou wrote:
>
>
> 2016-05-12 17:39 GMT+08:00 Michel Dänzer <michel at daenzer.net
> <mailto:michel at daenzer.net>>:
>
>     On 12.05.2016 17:58, Yu, Qiang wrote:
>     > Oh, what a crazy idea. So you mean it can work like this?
>     >
>     > 1. use the libgbm/gbm_dri/libEGL/libGLES from mesa which will load
>     > radeonsi_dri.so
>     >
>     > 2. libGL/amdgpu_dri.so from amdgpu-pro
>
>     glamor uses libEGL/GBM and libGL, so this could only work with Mesa's
>     libGL (or the GLVND one in the future). Can amdgpu_dri.so work with
>     Mesa's libGL right now?
>
>
> I think amdgpu_dri.so is not completely compatible with Mesa's libGL
> (considering some special feature requirements for amdgpu-pro and Mesa's
> evolving). Another problem is that Mesa's libgbm cannot share necessary
> buffer attributes (such as tiling info, etc) with amdgpu_dri.so at this
> moment.

I think the long-term plan for such attributes is passing them via 
amdgpu_bo_metadata (which is defined in libdrm's amdgpu.h). This 
metadata is read and written directly through libdrm_amdgpu, and so 
libgbm doesn't have to be involved as far as I can see.

Or is there some use-case that I'm forgetting where libgbm _does_ need 
those attributes?

Cheers,
Nicolai

>
>
>     Also, I'm afraid there might still be cases where amdgpu-pro supports
>     new hardware before radeonsi, in which case amdgpu_dri.so needs to
>     support GBM for glamor and EGL in general.
>
>
> IIRC radeonsi can support Southern Islands and later ASICs. I don't
> think amdgpu-pro can support pre-GCN products easily, given current
> amdgpu kernel driver support.
>
>
>
>     Also note that Nvidia developers were talking about possibly creating an
>     nvidia specific GBM backend recently on the wayland-devel mailing list.
>
>
> Will nvidia open source their code for GBM backend?
>
>
>
>     --
>     Earthling Michel Dänzer               | http://www.amd.com
>     Libre software enthusiast             |             Mesa and X developer
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