[Libva] I want to use VA-API to support new platform, I want know something about Intel implementation

[Randy Li]

On 08/18/2016 10:31 AM, Xiang, Haihao wrote:
>
> Hi Randy,
>
> You can get lots of information / docs via internet. You may search for
> dri, libdrm, drm, gem, i915 etc.
>
> dri wiki
> https://dri.freedesktop.org/wiki/
>
> drm:
> https://en.wikipedia.org/wiki/Direct_Rendering_Manager
>
> libdrm:
> https://01.org/linuxgraphics/community/libdrm
>
> intel graphics kernel
> https://01.org/linuxgraphics/community/kernel
I have read the documents you offered to me, I have a basic view of them 
and the relationship of them.

But I want to know more about the detail of Intel implementation.I have 
read the Intel driver of VA-API before, I think the Intel video process
video in this way.
1. Allocate the DRI buffer from the kernel driver using the libdrm.
2. Intel DRM driver in kernel would allocate buffer throught the GEM.
3. Intel VA-API driver push the codec data and parameters to those buffers
4. Got result from DRI buffer.

Is it correct ?

If it is correct, does it mean that the registers(used for configure 
decoding parameters) at Intel video processing unit would be mapped as 
PRIME buffers to be used in DRI?
And where is the kernel driver do that ? I know it is easy to find the 
DRM driver in linux kernel in drivers/gpu/drm/i915/ , but which file is
doing the job for video processing part? They looks like the graphics
to me. I think different Intel platform generation would have a 
different registers.

>
> Hope it can help you.
>
> Thanks
> Haihao
>
>
>> Hi all
>>    I am using VA-API to support the Video Process Unit in a ARM
>> platform, but it didn't use the standard kernel interface. Without
>> the
>> help of DRI, I can't implement something like vaDeriveImage() leading
>> a lose in performance.
>>    I read the Intel driver, it looks the Intel driver could access
>> the
>> the Memory of Video Unit of Intel Graphics card through the libdrm.
>> If that is right, could somebody told me how does it implemented in
>> linux kernel(which files?).
>> And I am really newbies to this area(DRI), could somebody give me
>> guide and documents about this?
>>    Thank you all very much.

Thank you so much.
-- 
Randy Li
The third produce department