NV_CIO_CRE_49
rd_cio_state(dev, head, regp, NV_CIO_CRE_49);
wr_cio_state(dev, head, regp, NV_CIO_CRE_49);
state->CRTC[NV_CIO_CRE_49] |= 0x10;
state->CRTC[NV_CIO_CRE_49] &= ~0x10;
NVWriteVgaCrtc(dev, head, NV_CIO_CRE_49,
state->CRTC[NV_CIO_CRE_49]);