NV_CIO_CR_MODE_INDEX
crtc17 |= (NVReadVgaCrtc(dev, nv_crtc->index, NV_CIO_CR_MODE_INDEX) & ~0x80);
NVWriteVgaCrtc(dev, nv_crtc->index, NV_CIO_CR_MODE_INDEX, crtc17);
regp->CRTC[NV_CIO_CR_MODE_INDEX] = 0x43;
saved_cr_mode = NVReadVgaCrtc(dev, 0, NV_CIO_CR_MODE_INDEX);
NVWriteVgaCrtc(dev, 0, NV_CIO_CR_MODE_INDEX, saved_cr_mode | 0x80);
NVWriteVgaCrtc(dev, 0, NV_CIO_CR_MODE_INDEX, saved_cr_mode);