On 4 August 2017 at 09:22, Chris Wilson <chris at chris-wilson.co.uk> wrote: > Quoting Dave Airlie (2017-08-04 00:01:10) >> On 4 August 2017 at 02:25, Chris Wilson <chris at chris-wilson.co.uk> wrote: >> > Quoting Dave Airlie (2017-05-12 01:34:55) >> >> @@ -385,6 +434,13 @@ drm_syncobj_fd_to_handle_ioctl(struct drm_device *dev, void *data, >> >> if (!drm_core_check_feature(dev, DRIVER_SYNCOBJ)) >> >> return -ENODEV; >> >> >> >> + if (args->flags & DRM_SYNCOBJ_FD_TO_HANDLE_FLAGS_IMPORT_SYNC_FILE_FENCE) >> >> + return drm_syncobj_import_sync_file_fence(file_private, >> >> + args->fd, >> >> + args->handle); >> >> + else if (args->flags) >> >> + return -EINVAL; >> > >> > Argh, what I missed before was that importing from a sync_file reuses >> > the handle, but importing from a syncobj fd creates a new handle. >> > >> > Just venting my ocd. It would be nice if the interface was consistent, >> > and I can see arguments for both approaches (just not a good argument as >> > to why they should differ). A compromise would be a flag to create/reuse >> > handle (or if handle=0, create, if handle!=0 resuse). >> >> The interface is consistent for the objects. >> >> With a sync_fd import you import the state into an existing syncobj. >> >> With a syncobj import you import the object into the current process state >> (so get a new handle). > > You can say the same for either path though, e.g. > > With a sync fd import you import the fence into the current process state > (so get a new handle). You import the fence, not the sync_fd. There is a difference here. A syncobj has a fence underlying it, it makes sense to import a new fence state into an existing object. It doesn't make sense to import a new syncobj into an existing object. It would be like importing a GEM object into a GEM object. I expect document it and be done is the best answer unless we can come up with a userspace use case that really expects the other behaviour. Dave.
