[Mesa-dev] change 396cbab, configs with accumulation buffer

[Tapani Pälli]

On 02/22/2016 11:41 AM, Kenneth Graunke wrote:
> On Monday, February 22, 2016 8:06:35 AM PST Tapani Pälli wrote:
>> Hi Marek;
>>
>> Was this commit fixing some issues/problems? Why would we not expose
>> configs with accumulation buffer?
>>
>> --- 8< ---
>> commit 396cbabbefaae64deac6d33c79898bb07db8a621
>> Author: Marek Olšák <marek.olsak at amd.com>
>> Date:   Thu Apr 9 23:25:07 2015 +0200
>>
>>       egl/dri: don't expose configs with an accumulation buffer
>> --- 8< ---
>>
>> Thanks;
>>
>> // Tapani
>
> Assuming it's legal not to expose them, it would certainly be nice.
> Accumulation buffers only exist in legacy GL (neither core profile nor
> GLES have ever had them), and our GLX implementation has marked them
> as "SLOW" for at least 12 years.

Right, I guess the only issue here is that even if you happen to have 
such buffer (capability?) in the visual it does not necessarily mean 
that it is in use. This change will remove all such configs, I'm not 
sure if that is generally a problem though, I guess it is up to the 
driver what it wants to expose.

I'm asking this because this patch causes a problem in internal project 
where they simply revert this patch currently, I will query more but I 
don't think they use such legacy feature.

> I don't recall the details, but I think it was some awful software
> fallback.  At any rate, I've never seen an application use them.
>
> --Ken
>

// Tapani