CTX_RING_HEAD
ce->lrc_reg_state[CTX_RING_HEAD + 1] = ce->ring->head;
regs[CTX_RING_HEAD + 1] = request->ring->head;
CTX_REG(regs, CTX_RING_HEAD, RING_HEAD(base), 0);
regs[CTX_RING_HEAD + 1] = ce->ring->head;