RADEON_CRTC2_DISP_DIS
CLR32(sc, RADEON_CRTC2_GEN_CNTL, RADEON_CRTC2_DISP_DIS);
RADEON_CRTC2_DISP_DIS | RADEON_CRTC2_DISP_REQ_EN_B);
mask = RADEON_CRTC2_DISP_DIS;