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See dma_fence_get_stub(). Got it. Thanks for your suggestions. Regards, Lang > Christian. > > > > > Signed-off-by: Lang Yu > > --- > > drivers/gpu/drm/amd/amdgpu/amdgpu_mes.c | 7 +++++-- > > 1 file changed, 5 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_mes.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_mes.c > > index f0f00466b59f..197981c4ac7d 100644 > > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_mes.c > > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_mes.c > > @@ -1043,8 +1043,11 @@ int amdgpu_mes_add_ring(struct amdgpu_device *adev, int gang_id, > > amdgpu_mes_ring_to_queue_props(adev, ring, &qprops); > > - dma_fence_wait(gang->process->vm->last_update, false); > > - dma_fence_wait(ctx_data->meta_data_va->last_pt_update, false); > > + if (gang->process->vm->last_update) > > + dma_fence_wait(gang->process->vm->last_update, false); > > + if (ctx_data->meta_data_va->last_pt_update) > > + dma_fence_wait(ctx_data->meta_data_va->last_pt_update, false); > > + > > amdgpu_mes_unlock(&adev->mes); > > r = amdgpu_mes_add_hw_queue(adev, gang_id, &qprops, &queue_id); >