[Mesa-dev] GBM backend dynamic dispatch method

[Axel Davy]

Another question:

Why not just use Mesa handle gbm ?
If I understand radeonsi uses the same libdrm and kernel than amdgpu-pro.

Thus having Mesa handle gbm should be fine, as radeonsi could work 
alongside amdgpu-pro.

Then the only implementation details are about the extension to import 
gbm bo into EGLImage (and the gbm code to import EGLImage)
Importing into EGL can be done with gbm function to export dma-buf (and 
then the dma-buf would get imported for EGLImage).
Not sure for the other way, but it could be made possible.

Also next question would be: why not let radeonsi handle EGL (and gbm), 
and have amdgpu-pro handle glx only ?
That way amdgpu-pro won't need to duplicate the code for wayland 
support, gbm support, etc.

Axel

On 12/05/2016 09:10, Yu, Qiang wrote :
>
> Thanks Axel, I find the current GBM already works like you said except
>
> GBM_BACKEND only support one backend. So I just have to make amdgpu-pro
>
> backend create_device return NULL for Intel GPU.
>
>
> Many thanks,
>
> Qiang
>
> ------------------------------------------------------------------------
> *From:* mesa-dev <mesa-dev-bounces at lists.freedesktop.org> on behalf of 
> Axel Davy <axel.davy at ens.fr>
> *Sent:* Thursday, May 12, 2016 2:36:34 PM
> *To:* mesa-dev at lists.freedesktop.org
> *Subject:* Re: [Mesa-dev] GBM backend dynamic dispatch method
> Hi,
>
> I'm not sure if that answers your need, but to me it looks like
> it would be simpler if gbm was trying different backends for the given
> device, until it succeeds. You'd pass several backends to GBM_BACKEND 
> (perhaps
> rename to GBM_BACKENDS), and in your example it would put amdgpu pro 
> first.
> Then when using the amd card, amdgpu pro would be used, else since the 
> loading
> would fail, it would use the second backend, which would be mesa.
>
> That's just a suggestion, and you'd better wait for gbm maintainers to 
> voice theirs.
>
> Axel
>
> On 12/05/2016 04:45, Yu, Qiang wrote:
>>
>> Hi guys,
>>
>>
>> Let me introduce myself. My name is Qiang Yu, I'm a developer 
>> of amdgpu-pro driver.
>>
>> As you know the amdgpu-pro adopts some open source part like GBM but 
>> due to its
>>
>> close source OGL part, we implement our own GBM backend.
>>
>>
>> Currently libgbm only support static selection of GBM backend by 
>> GBM_BACKEND,
>>
>> so for the hybrid GPU case like Intel iGPU + AMD dGPU and AMD dGPU is 
>> drived
>>
>> by amdgpu-pro, it's not convenient for client to switch backend all 
>> the time and even
>>
>> impossible for applications that need to deal with both GPUs like the 
>> XServer.
>>
>>
>> So I'm wondering a dynamic dispatch method and hope it can go 
>> upstream to the libgbm:
>>
>> 1. create a /etc/gbm/xxx.conf for libgbm to read when none default 
>> backend needed
>>
>> 2. the content should be like: <kernel driver name>:<gbm backend name>
>>
>>     In the amdgpu-pro case, the content is: amdgpu:gbm_amdgpu.so
>>
>>
>> This method need libgbm use libdrm to determine the FD kernel driver 
>> first.
>>
>> Any feedback on this method and the hope to go upstream?
>>
>>
>> Thanks,
>>
>> Qiang
>>
>>
>>
>>
>> _______________________________________________
>> mesa-dev mailing list
>> mesa-dev at lists.freedesktop.org
>> https://lists.freedesktop.org/mailman/listinfo/mesa-dev
>
>

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