[Linaro-mm-sig] [RFC v2 1/2] dma-buf: Introduce dma buffer sharing mechanism
anca.emanuel at gmail.com
Tue Dec 20 09:29:42 EST 2011
On Tue, Dec 20, 2011 at 4:05 AM, Robert Morell <rmorell at nvidia.com> wrote:
> One of the goals of this project is to unify the fragmented space of the
> ARM SoC memory managers so that each vendor doesn't implement their own,
> and they can all be closer to mainline.
That is a very good objective.
> I fear that restricting the use of this buffer sharing mechanism to GPL
> drivers only will prevent that goal from being achieved, if an SoC
> driver has to interact with modules that use a non-GPL license.
If nobody from nvidia have any experience with this kind of work...
Look at Intel. Why are you afraid of ?
> As a hypothetical example, consider laptops that have multiple GPUs.
> Today, these ship with onboard graphics (integrated to the CPU or
> chipset) along with a discrete GPU, where in many cases only the onboard
> graphics can actually display to the screen. In order for anything
> rendered by the discrete GPU to be displayed, it has to be copied to
> memory available for the smaller onboard graphics to texture from or
> display directly. Obviously, that's best done by sharing dma buffers
> rather than bouncing them through the GPU. It's not much of a stretch
> to imagine that we'll see such systems with a Tegra CPU/GPU plus a
> discrete GPU in the future; in that case, we'd want to be able to share
> memory between the discrete GPU and the Tegra system. In that scenario,
> if this interface is GPL-only, we'd be unable to adopt the dma_buffer
> sharing mechanism for Tegra.
> (This isn't too pie-in-the-sky, either; people are already combining
> Tegra with discrete GPUs:
There are other problems ? Some secret agreements with Microsoft ?
I hope to see something open sourced. You can do it nVidia.
More information about the linux-arm-kernel