BT848_COLOR_CTL
btwrite(BT848_COLOR_CTL_GAMMA, BT848_COLOR_CTL);
~0x0f, BT848_COLOR_CTL);
btaor(set->top->btswap & 0x0f, ~0x0f, BT848_COLOR_CTL);
btaor(set->bottom->btswap & 0x0f, ~0x0f, BT848_COLOR_CTL);