On 10/28/2016 07:48 PM, Christian König wrote: > 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. > Done. Patch v2 just sent out after retesting with Tonga only and Intel + Tonga renderoffload. Would be cool if we could get this into 4.9-rc. Ideally also backported to 4.8, given it is a simple change, as that would be the next official kernel for *buntu 16.04-LTS and derivatives, but that's probably breaking the rules as it doesn't fix a regression? thanks, -mario > Regards, > Christian. > >> >> All i can say is it fixes 3D rendering under DRI3 + Prime + >> pageflipping without causing any obvious new problems. >> >> -mario > >
