[PATCH v4] dma-buf: Add ioctls to allow userspace to flush

[Tiago Vignatti]

On 08/26/2015 09:58 AM, Daniel Vetter wrote:
> The other is that right now there's no user nor implementation in sight
> which actually does range-based flush optimizations, so I'm pretty much
> expecting we'll get it wrong. Maybe instead we should go one step further
> and remove the range from the internal dma-buf interface and also drop it
> from the ioctl? With the flags we can always add something later on once
> we have a real user with a clear need for it. But afaik cros only wants to
> shuffle around entire tiles and has a buffer-per-tile approach.

Thomas, I think Daniel has a point here and also, I wouldn't mind 
removing all range control from the dma-buf ioctl either.

In this last patch we can see that it's not complicated to add the 
2d-sync if we eventually decides to want it. But right now there's no 
way we can test it. Therefore in that case I'm all in favour of doing 
this work gradually, adding the basics first.

Tiago