AMDGPU_DOORBELL_MEC_RING0
ring->doorbell_index = AMDGPU_DOORBELL_MEC_RING0 + ring_id;
ring->doorbell_index = AMDGPU_DOORBELL_MEC_RING0 + ring_id;
ring->doorbell_index = (AMDGPU_DOORBELL_MEC_RING0 + ring_id) << 1;