Am 28.10.2016 um 19:37 schrieb Mario Kleiner: > > > On 10/28/2016 03:34 AM, Michel Dänzer wrote: >> On 27/10/16 10:33 PM, Mike Lothian wrote: >>> >>> Just another gentle ping to see where you are with this? >> >> I haven't got a chance to look into this any further. >> >> > > Fwiw., as a proof of concept, the attached experimental patch does > work as tested on Intel HD Haswell + AMD R9 380 Tonga under amdgpu and > DRI3/Present when applied to drm-next (updated from a few days ago). > With DRI_PRIME=1 tearing for page-flipped fullscreen windows is gone > under all loads. The tearing with "windowed" windows now looks as > expected for regular tearing not related to Prime. Yeah, that's pretty much what I had in mind as well. You additionally need to wait for the shared fences when you export the BO for the first time, but that's only a nitpick. > > ftrace confirms the i915 driver's pageflip function is waiting on the > fence in reservation_object_wait_timeout_rcu() as it should. > > That entry->tv.shared needs to be set false for such buffers in > amdgpu_bo_list_set() makes sense to me, as that is part of the buffer > validation for command stream submission. There are other places in > the driver where tv.shared is set, which i didn't check so far. > > I don't know which of these would need to be updated with a "exported > bo" check as well, e.g., for video decoding or maybe gpu compute? > Adding or removing the check to amdgpu_gem_va_update_vm(), e.g., made > no difference. I assume that makes sense because that functions seems > to deal with amdgpu internal vm page tables or page table entries for > such a bo, not with something visible to external clients? Yes, exactly. VM updates doesn't matter for anybody else than amdgpu. Additional to that we don't even add a fence to the shared slot we reserve (could probably drop that for optimization). Please remove the debugging stuff and the extra code on the VM updates and add a reservation_object_wait_timeout_rcu() to the export path and we should be good to go. Regards, Christian. > > All i can say is it fixes 3D rendering under DRI3 + Prime + > pageflipping without causing any obvious new problems. > > -mario
