[Mesa-dev] [PATCH] st/mesa: conditionally enable GL_NV_vdpau_interop

[Ilia Mirkin]

On Fri, Jan 22, 2016 at 2:11 PM, Christian König
<deathsimple at vodafone.de> wrote:
> Am 22.01.2016 um 19:24 schrieb Ilia Mirkin:
>>
>> On Fri, Jan 22, 2016 at 1:15 PM, Christian König
>> <deathsimple at vodafone.de> wrote:
>>>>
>>>> Form autofoo perspective things look great.
>>>
>>> Thanks, that exactly what I wanted to know.
>>>
>>>> Although I second Ilia's concern - we need a form of runtime detection
>>>> here. Pretty much all distros ship the vdpau(+ other video driver
>>>> backend) in a separate library. Thus this will likely get us nowhere
>>>> we want - as I'm suspecting this is to assist the unsuspecting user,
>>>> which hasn't installed package X or Y in the first place ?
>>>
>>> As I said, Mesa should NOT check what vdpau backend libraries are
>>> installed
>>> or used before advertising NV_vdpau_interop.
>>>
>>> Take a look at how the interop works, NV_vdpau_interop should be
>>> advertised
>>> if the OpenGL implementation provides the necessary functions. What and
>>> if a
>>> VDPAU backend gets loaded to work with that is completely independent of
>>> this.
>>>
>>> We want to switch over to a DMABuf based interop implementation so that
>>> we
>>> can get away from using the Mesa internal structures.
>>>
>>> This not only has the advantage of fixing this ugly hack, but also would
>>> allow an application to decode on one driver (radeonsi) and display with
>>> another one (r600).
>>
>> If the purpose is not to conditionally not advertise based on
>> availability, what is the purpose of this patch?
>
>
> To check if we compile the state tracker as well and so fulfill the
> dependencies of the state tracker.
>
> E.g. for example for a DMABuf based interop I might need some defines from
> the VDPAU headers.
>
> The alternative is to make the OpenGL implementation depend on the presence
> of libvdpau directly, but I had the feeling that this approach would be more
> convenient.
>
> Sorry for the confusion, I never intended to make any this an extra check
> for the unsuspecting user. But rather just solve the dependencies without
> checking for libvdpau twice.
>
> I should have probably better explained that in the first place.

Aha I see, so this is a prelude to some changes you'd like to make
that would cause various breakage if you didn't also have all the
vdpau stuff being built.

In that case, this is Reviewed-by: Ilia Mirkin <imirkin at alum.mit.edu>