READ_TIMEOUT
WREG32_FIELD15(GC, 0, GRBM_CNTL, READ_TIMEOUT, 0xff);
WREG32_FIELD15_PREREG(GC, 0, GRBM_CNTL, READ_TIMEOUT, 0xff);
WREG32_FIELD15_PREREG(GC, 0, GRBM_CNTL, READ_TIMEOUT, 0xff);
WREG32_FIELD(GRBM_CNTL, READ_TIMEOUT, 0xFF);
WREG32_FIELD15_RLC(GC, 0, GRBM_CNTL, READ_TIMEOUT, 0xff);