Hi
On Thu, Dec 10, 2015 at 2:28 PM, Martin Peres martin.peres@linux.intel.com wrote:
Yes, you are right, it will require changes for the non-X case.
Since you spent a lot of time on it, could you share with us some of the issues you found? We still think that using the DRM interface may be more work, but at least it would improve the state of the graphics stack.
The biggest issue is that most compositors are built around the assumption that one/_the_ DRM card is always accessible and usable. That is, they hard-code a fixed path to /dev/dri/cardX and use it. They cannot deal with hotplugging of DRM cards, they cannot deal with no card being present and they cannot rate cards and evaluate whether a card is something they want to use or not. That infrastructure is just not available in any compositor I have seen, and it is non-trivial to write.
Apart from that, the biggest problem I see is that multi-GPU systems are usually non-standard. You *have* to know the exact setup beforehand to make it work properly. It is hard to write a heuristic that properly detects which cards should be used in what way.
Thanks David