modesetting TearFree / VSYNC aware rotation pageflipping

[Michel Dänzer]

On 2018-10-03 4:22 p.m., Carsten Behling wrote:
> 
>> TearFree uses separate dedicated scanout buffers, to which the "main"
>> buffer contents are copied on demand.
>>
>> Originally, these three things (DRI page flipping, rotation and
>> TearFree) were separate and mutually exclusive. However, the
>> amdgpu/radeon drivers support all of them the same time these days; this
>> still requires an extra copy in some cases, but that could be eliminated
>> at least in the non-rotated DRI page flipping case.
>>
>> https://gitlab.freedesktop.org/xorg/xserver/merge_requests/24 has the
>> start of TearFree support for the modesetting driver, but it's still
>> mutually exclusive with rotation (DRI3 page flipping should work with
>> TearFree, but may still exhibit tearing if the client/user disables
>> sync-to-vblank).
> 
> Couldn't we extend modesetting in addition to Martin's TearFree patch the
> same way you did here for Radeon?:
> 
> https://cgit.freedesktop.org/xorg/driver/xf86-video-ati/commit/?id=798c4fd16d339b1ad5fd729cc884be084c60e38b

Yeah, something like that would be needed.


-- 
Earthling Michel Dänzer               |               http://www.amd.com
Libre software enthusiast             |             Mesa and X developer