On Mon, Apr 9, 2018 at 6:57 AM, Volker Vogelhuber <v.vogelhu...@digitalendoscopy.de> wrote: > Thanks for the response. I'm a bit confused. What is the difference between > a PRIME handle and a generic DMABUF file descriptor? I'm importing a buffer > from V4L2 into an Nvidia context. So the FD is backed by the V4L2's > vb2_queue used in the UVC driver which provides the FD by using the > VIDIOC_EXPBUF ioctl. I doubt that there is a GEM object associated with it > at all, as V4L2 is probably not aware of GEM, is it?
Right, there probably isn't. I'm also not 100% sure it's required, just seemed like it may be based on a quick glance at the code. > > I would have guessed, that the use case would be quite common, as having a > Live video source rendered via OpenGL shouldn't be a very special topic and > having a zero copy approach should be better than having to copy the data Having a live video source is a pretty special topic. (Esp having one that you ever use.) > all the time. Would allocating a buffer in the GPU and exporting it via > eglCreateDRMImageMESA an option. Then I would have to import that buffer > into V4L2 via V4L2_MEMORY_DMABUF. But as eglCreateDRMImageMESA only accepts > EGL_DRM_BUFFER_FORMAT_ARGB32_MESA it's not very flexible regarding V4L2 > input formats. Apart from that, I think those buffers use GPU specific > tiling/swizzling, so V4L2 won't be able to properly write data into it. So > having the GPU importing the buffer from V4L2 seems to be more straight > forward to me and as the i915 is able to do exactly this, and the > code/interfaces are the same for nouveau I wouldn't expect the nouveau > driver to behave differently. Well, clearly it does. I'm not particularly surprised, since, like I said, it seems likely that you're the first to attempt it (or at least inquire as to its failure after attempting it). If you're interested in debugging this, I'd recommend joining #nouveau on irc.freenode.net. Otherwise, focus on hardware whose makers invest in open-source GL drivers -- i.e. not NVIDIA. -ilia _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/mesa-dev
