CR11
par->regs.cr11 = i810_readb(CR11, mmio) & ~0x0F;
i810_writeb(CR_INDEX_CGA, mmio, CR11);
i810_writeb(CR_INDEX_CGA, mmio, CR11);
i810_writeb(CR_INDEX_CGA, mmio, CR11);
{VIACR, CR11, 0xF0, 0x80}, /* [0-3] vertical retrace end
viafb_write_reg_mask(CR11, VIACR, BIT7, BIT7);
viafb_write_reg_mask(CR11, VIACR, 0, BIT7);