NV_VIO_GX_MISC_INDEX
regp->Graphics[NV_VIO_GX_MISC_INDEX] = 0x05; /* map 64k mem + graphic mode */
gr6 = NVReadVgaGr(dev, 0, NV_VIO_GX_MISC_INDEX);
NVWriteVgaGr(dev, 0, NV_VIO_GX_MISC_INDEX, 0x5);
NVWriteVgaGr(dev, 0, NV_VIO_GX_MISC_INDEX, gr6);