On Wed, Feb 24, 2021 at 11:30:50AM -0500, Andrey Grodzovsky wrote: > > On 2021-02-19 5:24 a.m., Daniel Vetter wrote: > > On Thu, Feb 18, 2021 at 9:03 PM Andrey Grodzovsky > > <Andrey.Grodzovsky@xxxxxxx> wrote: > > > Looked a bit into it, I want to export sync_object to FD and import from that FD > > > such that I will wait on the imported sync object handle from one thread while > > > signaling the exported sync object handle from another (post device unplug) ? > > > > > > My problem is how to create a sync object with a non signaled 'fake' fence ? > > > I only see API that creates it with already signaled fence (or none) - > > > https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Felixir.bootlin.com%2Flinux%2Flatest%2Fsource%2Fdrivers%2Fgpu%2Fdrm%2Fdrm_syncobj.c%23L56&data=04%7C01%7CAndrey.Grodzovsky%40amd.com%7C5085bdd151c642514d2408d8d4c08e56%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637493270792459284%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=sZWIn0Lo7ZujBq0e7MdFPhJDARXWpOlLgLzANMS8cCY%3D&reserved=0 > > > > > > P.S I expect the kernel to crash since unlike with dma_bufs we don't hold > > > drm device reference here on export. > > Well maybe there's no crash. I think if you go through all your > > dma_fence that you have and force-complete them, then I think external > > callers wont go into the driver anymore. But there's still pointers > > potentially pointing at your device struct and all that, but should > > work. Still needs some audit ofc. > > > > Wrt how you get such a free-standing fence, that's amdgpu specific. Roughly > > - submit cs > > - get the fence for that (either sync_file, but I don't think amdgpu > > supports that, or maybe through drm_syncobj) > > - hotunplug > > - wait on that fence somehow (drm_syncobj has direct uapi for this, > > same for sync_file I think) > > > > Cheers, Daniel > > > Indeed worked fine, did with 2 devices. Since syncobj is refcounted, even > after I > destroyed the original syncobj and unplugged the device, the exported > syncobj and the > fence inside didn't go anywhere. > > See my 3 tests in my branch on Gitlab > https://gitlab.freedesktop.org/agrodzov/igt-gpu-tools/-/commits/master > and let me know if I should go ahead and do a merge request (into which > target project/branch ?) or you > have more comments. igt still works with patch submission. -Daniel > > Andrey > > > > > > > Andrey > > > > > > On 2/9/21 4:50 AM, Daniel Vetter wrote: > > > > Yeah in the end we'd need 2 hw devices for testing full fence > > > > functionality. A useful intermediate step would be to just export the > > > > fence (either as sync_file, which I think amdgpu doesn't support because > > > > no android egl support in mesa) or drm_syncobj (which you can do as > > > > standalone fd too iirc), and then just using the fence a bit from > > > > userspace (like wait on it or get its status) after the device is > > > > unplugged. > > > > -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
