RADEON_DAC_RANGE_CNTL_MASK
value = old_dac_cntl & ~(RADEON_DAC_RANGE_CNTL_MASK | RADEON_DAC_PDWN);
values->dac_cntl &= ~(RADEON_DAC_RANGE_CNTL_MASK | RADEON_DAC_BLANKING);