[PATCH] drm/amdgpu: Attach exclusive fence to prime exported bo's. (v3)
Michel Dänzer
michel at daenzer.net
Mon Nov 7 03:29:12 UTC 2016
On 07/11/16 11:47 AM, Mario Kleiner wrote:
> External clients which import our bo's wait only
> for exclusive dmabuf-fences, not on shared ones,
> so attach fences on exported buffers as exclusive
> ones, if the buffers get imported by an external
> client.
>
> See discussion in thread:
> https://lists.freedesktop.org/archives/dri-devel/2016-October/122370.html
>
> Tested on Intel iGPU + AMD Tonga dGPU as DRI3/Present
> Prime render offload, and with the Tonga standalone as
> primary gpu.
>
> v2: Add a wait for all shared fences before prime export,
> as suggested by Christian Koenig.
>
> v3: - Mark buffer prime_exported in amdgpu_gem_prime_pin,
> so we only use the exclusive fence when exporting a
> bo to external clients like a separate iGPU, but not
> when exporting/importing from/to ourselves as part of
> regular DRI3 fd passing.
>
> - Propagate failure of reservation_object_wait_rcu back
> to caller.
>
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=95472
> (v1) Tested-by: Mike Lothian <mike at fireburn.co.uk>
FWIW, I think the (v1) is usually added at the end of the line, not at
the beginning.
[...]
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_prime.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_prime.c
> index 7700dc2..c4494d0 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_prime.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_prime.c
> @@ -81,6 +81,20 @@ int amdgpu_gem_prime_pin(struct drm_gem_object *obj)
> {
> struct amdgpu_bo *bo = gem_to_amdgpu_bo(obj);
> int ret = 0;
> + long lret;
> +
> + /*
> + * Wait for all shared fences to complete before we switch to future
> + * use of exclusive fence on this prime_exported bo.
> + */
> + lret = reservation_object_wait_timeout_rcu(bo->tbo.resv, true, false,
> + MAX_SCHEDULE_TIMEOUT);
> + if (unlikely(lret < 0)) {
> + DRM_DEBUG_PRIME("Fence wait failed: %li\n", lret);
> + return lret;
> + }
> +
> + bo->prime_exported = true;
We should probably clear bo->prime_exported in amdgpu_gem_prime_unpin.
Also, I think we should set bo->prime_exported (prime_shared?) in
amdgpu_gem_prime_import_sg_table as well, so that we'll also set
exclusive fences on BOs imported from other GPUs.
--
Earthling Michel Dänzer | http://www.amd.com
Libre software enthusiast | Mesa and X developer
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