PBF_REG_P0_ARB_THRSH
REG_WR(bp, PBF_REG_P0_ARB_THRSH + port*4, 0);
REG_WR(bp, PBF_REG_P0_ARB_THRSH + port*4, thresh);
REG_WR(bp, PBF_REG_P0_ARB_THRSH + port*4, (9040/16));