[PATCH v2 0/3] A DRM API for adaptive sync and variable refresh rate support

[Koenig, Christian]

Am 12.10.2018 um 10:26 schrieb Michel Dänzer:
> On 2018-10-11 9:44 p.m., Harry Wentland wrote:
>> On 2018-10-03 04:25 AM, Mike Lothian wrote:
>>> I'm curious to know whether this will/could work over PRIME
>> I don't see why this shouldn't work over PRIME as long as the
>> presenting GPU supports the new variable refresh rate API, but I know
>> very little about prime, so maybe someone else can chime in and give
>> a better opinion.
> It won't work for displays connected to a secondary GPU, because those
> aren't hooked up to the Present extension directly.
>
> It can theoretically work with render offloading, if the primary GPU can
> scan out directly from the shared pixmap. This is only possible with
> current AMD APUs which support scatter/gather scanout (Carrizo and
> newer?).

Actually only Carizzo and Stoney at the moment because this is buggy on 
Raven. Not sure if that is a pure software or a hardware problem.

Christian.

> One gotcha is that xf86-video-amdgpu currently doesn't allow
> flipping between buffers with different tiling parameters (BTW Harry,
> does that work with DC?), but that should be easy to fix.