On Sat, Jan 21, 2012 at 11:02 PM, Daniel Vetter daniel@ffwll.ch wrote:
On Fri, Jan 20, 2012 at 10:04:57AM -0800, Robert Morell wrote:
On Wed, Jan 18, 2012 at 01:10:04AM -0800, Semwal, Sumit wrote:
On Wed, Jan 18, 2012 at 5:38 AM, Robert Morell rmorell@nvidia.com wrote:
EXPORT_SYMBOL_GPL is intended to be used for "an internal implementation issue, and not really an interface". The dma-buf infrastructure is explicitly intended as an interface between modules/drivers, so it should use EXPORT_SYMBOL instead.
- Konrad, Arnd, Mauro: there were strong objections on using
EXPORT_SYMBOL in place of EXPORT_SYMBOL_GPL by all 3 of them; I suggest we first arrive at a consensus before merging this patch.
This discussion seems to have stagnated; how do we move forward here?
Sumit, as the primary author and new maintainer (congrats!) of the dma-buf infrastructure, it seems like it's really your call how to proceed. I'd still like to see this be something that we can use from the nvidia and fglrx drivers for Xorg buffer sharing, as I and Dave have argued in this thread. It really seems to me that this change on a technical level won't have any adverse effect on the scenarios where it can be used today, but it will allow it to be used more widely, which will prevent duplication and fragmentation in the future and be greatly appreciated by users of hardware such as Optimus.
Given that I've participated quite a bit in the design of dma_buf as-is, let me throw in my totally irrelevant opinion, too ;-)
I'll refrain from comment on the actual patch, it's obviously a hot topic. Furthermore I might need to ask Intel's legal dep for guidance to asses things wrt my own contributions to dma_buf.
Otoh I'd like nvidia to be on board, especially when we're desingned additions to dma_buf required to make it really work for multiple gpus. In additions it looks like that the nvidia blob will only be an importer of a dma_buf, at least for the use-cases discussed here.
So why don't you just ditch this patch here and add a small shim to your blob to interface with drm's prime as an importing driver? I personally would deem that acceptable and I think Dave wouldn't mind too much, either.
Hi Everyone!
(Apologies for delay in replying; was OoO for past couple of days)
Thanks very much for this discussion - a couple of things:
1. I am definitely willing to make changes as needed to get as many devices / subsystems / frameworks to use the dma-buf infrastructure. This could include changing the way symbols are exported, if that is the *only* way to get things done.
2. With that premise, I quite like the idea that Daniel gave (of course, in his capacity as one of the top contributors behind dma-buf infrastructure, and like he said, not as an Intel employee) - so let me ask the following:
Robert, Dave, Technically speaking, is there no way that the EXPORT_SYMBOL_GPLed symbols can be used by the binary blobs, possibly with an open-sourced shim which provides the buffer-sharing interface to the binary blobs? Are there any reasons to not consider this approach?
Also, if some of you are going to be at ELC mid-Feb at SFO, we could meet up face-to-face and thrash out possible ways forward.
Yours, Daniel
Thanks, and best regards, ~Sumit.
Disclaimer: This is my own opinion and I do not speak as an Intel employee here. -- Daniel Vetter Mail: daniel@ffwll.ch Mobile: +41 (0)79 365 57 48