(This is an RFC on whether this pair of ioctls seems reasonable. The code compiles, but I haven't tested it as I'm away from home this weekend.) I'm rewriting my implementation of the Vulkan EXT_display_control extension, which provides a way to signal a Vulkan fence at vblank time. I had implemented it using events, but that isn't great as the Vulkan API includes the ability to wait for any of a set of fences to be signaled. As the other Vulkan fences are implemented using dma_fences in the kernel, and (eventually) using syncobj up in user space, it seems reasonable to use syncobjs for everything and hook vblank to those. In any case, I'm proposing two new syncobj/vblank ioctls (the names aren't great; suggestions welcome, as usual): DRM_IOCTL_CRTC_QUEUE_SYNCOBJ Create a new syncobj that will be signaled at (or after) the specified vblank sequence value. This uses the same parameters to specify the target sequence as DRM_IOCTL_CRTC_QUEUE_SEQUENCE. DRM_IOCTL_CRTC_GET_SYNCOBJ Once the above syncobj has been signaled, this ioctl allows the application to find out when that happened, returning both the vblank sequence count and time (in ns). I'd like to hear comments on whether this seems reasonable, or whether I should go in some other direction. _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
