DMA-buf and uncached system memory

[Christian König <christian.koenig@xxxxxxx>]

Hi guys,

we are currently working an Freesync and direct scan out from system 
memory on AMD APUs in A+A laptops.

On problem we stumbled over is that our display hardware needs to scan 
out from uncached system memory and we currently don't have a way to 
communicate that through DMA-buf.

For our specific use case at hand we are going to implement something 
driver specific, but the question is should we have something more 
generic for this?

After all the system memory access pattern is a PCIe extension and as 
such something generic.

Regards,
Christian.