RADEON_CLOCK_CNTL_DATA
(void)RREG32(RADEON_CLOCK_CNTL_DATA);
tmp = RREG32(RADEON_CLOCK_CNTL_DATA);
data = RREG32(RADEON_CLOCK_CNTL_DATA);
WREG32(RADEON_CLOCK_CNTL_DATA, v);
WREG8(RADEON_CLOCK_CNTL_DATA + 3, 0);
if (RREG8(RADEON_CLOCK_CNTL_DATA + 3) >= cnt_threshold)