[Mesa-dev] GLX extension for vendor name lookup in libglvnd

[Kyle Brenneman]

On 03/11/2016 05:25 PM, Martin Peres wrote:
>
>
> On 10/03/16 20:07, Adam Jackson wrote:
>> On Thu, 2016-03-10 at 10:53 -0700, Kyle Brenneman wrote:
>>> On 03/10/2016 10:47 AM, Martin Peres wrote:
>>>> That could be a hacky way of handling the case where multiple 3D
>>>> drivers could be used to drive the same GPU. This may be necessary in
>>>> the future if two mesa drivers support the same GPU but one is
>>>> considered better than the other. We can also imagine a case where a
>>>> proprietary driver would need to be co-installable with an open source
>>>> one and would still use the same DDX. Isn't that what AMD is going to
>>>> do soon? Did anyone think about this case?
>>> That case is the reason for allowing multiple vendor names. For a case
>>> like AMD's driver, it would hand back two names. The order would be up
>>> to the driver implementation, but I would guess that it would list the
>>> proprietary driver first and the open source driver second. If the
>>> proprietary one is installed, then the client would use it, and if not,
>>> the client would use the open source one.
>
> Very good! That could be worth mentioning in the spec. To make it 
> clear that it is the intended goal and to help implementers understand 
> the logic behind this proposal.
That's what I meant to convey with the description of multiple 
client-side drivers that work with the same server-side driver. But if 
that wasn't clear I can add a more specific example. Would something 
like this help?


     For example, some vendors may have both a proprietary client-side
     vendor library and an open source vendor library that work with the
     same server-side driver. In that case, the server would return the
     names for both of the vendor libraries. The client would then be able
     to select one of those vendor libraries, depending on which of them is
     installed.


>>
>> Right. It's pretty straightforward (and I plan) to wire this logic
>> through to xorg.conf, so the admin can control the list at server
>> startup time. Historically it's been somewhat pointless to do so, since
>> all the proprietary drivers have also replaced the server's GLX module,
>> but this gives us a path towards not doing that anymore at least.
>>
>> I'd also considered using this mechanism as a starting path towards
>> both implementing GLX+Xinerama at all for the open drivers, and
>> eventually to do that with heterogeneous open/closed GLX on the server
>> side. Those are both fairly long term prospects, but I imagine it'll be
>> easier to do if we can opt into different client-side logic.
>
> Sounds indeed like a good thing to have! Accelerated xinerama using 
> prime and reverse prime on multiple drivers :)
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