[Mesa-dev] [PATCH dri3proto v2] Add modifier/multi-plane requests, bump to v1.1

[Marek Olšák]

On Wed, Jul 26, 2017 at 8:29 AM, Michel Dänzer <michel at daenzer.net> wrote:
> On 25/07/17 05:28 PM, Nicolai Hähnle wrote:
>> On 22.07.2017 14:00, Daniel Stone wrote:
>>>
>>> I don't have any great solution off the top of my head, but I'd be
>>> inclined to bundle stride in with placement. TTBOMK (from having
>>> looked at radv), buffers shared cross-GPU also need to be allocated
>>> from a separate externally-visible memory heap. And at the moment,
>>> lacking placement information at allocation time (at least for EGL
>>> allocations, via DRIImage), that happens via transparent migration at
>>> import time I think. Placement restrictions would probably also
>>> involve communicating base address alignment requirements.
>>
>> Stride isn't really in the same category as placement and base address
>> alignment, though.
>>
>> Placement and base address alignment requirements can apply to all
>> possible texture layouts, while the concept of stride is specific to
>> linear layouts.
>
> Also, the starting address of shareable buffers is generally aligned to
> at least the CPU page size anyway. Do we know of any cases requiring
> higher alignment than that, and if so, which address space does the
> requirement apply to?

The highest base address alignment I know of is 2D tiling on Fiji =
256KB alignment.

Marek