Trying to grab dma_resv_lock while in commit_tail before we've done all the code that leads to the eventual signalling of the vblank event (which can be a dma_fence) is deadlock-y. Don't do that.
Here the solution is easy because just grabbing locks to read something races anyway. We don't need to bother, READ_ONCE is equivalent. And avoids the locking issue. v2: Also take into account tmz_surface boolean, plus just delete the old code. Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: Chris Wilson <[email protected]> Cc: Maarten Lankhorst <[email protected]> Cc: Christian König <[email protected]> Signed-off-by: Daniel Vetter <[email protected]> --- DC-folks, I think this split out patch from my series here https://lore.kernel.org/dri-devel/[email protected]/ should be ready for review/merging. I fixed it up a bit so that it's not just a gross hack :-) Cheers, Daniel --- .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 19 ++++++------------- 1 file changed, 6 insertions(+), 13 deletions(-) diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c index 21ec64fe5527..a20b62b1f2ef 100644 --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c @@ -6959,20 +6959,13 @@ static void amdgpu_dm_commit_planes(struct drm_atomic_state *state, DRM_ERROR("Waiting for fences timed out!"); /* - * TODO This might fail and hence better not used, wait - * explicitly on fences instead - * and in general should be called for - * blocking commit to as per framework helpers + * We cannot reserve buffers here, which means the normal flag + * access functions don't work. Paper over this with READ_ONCE, + * but maybe the flags are invariant enough that not even that + * would be needed. */ - r = amdgpu_bo_reserve(abo, true); - if (unlikely(r != 0)) - DRM_ERROR("failed to reserve buffer before flip\n"); - - amdgpu_bo_get_tiling_flags(abo, &tiling_flags); - - tmz_surface = amdgpu_bo_encrypted(abo); - - amdgpu_bo_unreserve(abo); + tiling_flags = READ_ONCE(abo->tiling_flags); + tmz_surface = READ_ONCE(abo->flags) & AMDGPU_GEM_CREATE_ENCRYPTED; fill_dc_plane_info_and_addr( dm->adev, new_plane_state, tiling_flags, -- 2.27.0 _______________________________________________ dri-devel mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/dri-devel
