DAC_PDWN
aty_st_le32(DAC_CNTL, aty_ld_le32(DAC_CNTL) & (~DAC_PDWN));
aty_st_le32(DAC_CNTL, aty_ld_le32(DAC_CNTL) | DAC_PDWN);
| DAC_PDWN);