PBF_REG_P0_ARB_THRSH
REG_WR(cb, PBF_REG_P0_ARB_THRSH + port*4, 0);
REG_WR(cb, PBF_REG_P0_ARB_THRSH + port*4, thresh);
REG_WR(pdev,(PORT_ID(pdev) ? PBF_REG_P1_ARB_THRSH : PBF_REG_P0_ARB_THRSH),(MAXIMUM_PACKET_SIZE/16));