Coffee Lake (Tested on i5-9300H) Backlight Set Logic

gistfile1.txt

    // coffee lake chips use the BXT methods.
    current = INREG(0xC8258);
    max = INREG(0xC8254);

    printf ("current backlight value: %d%%\n", current * 100 / max);

    if (argc > 1) {
        uint32_t v = atoi (argv[1]) * max / 100;
        if (v > max)
            v = max;
        OUTREG(0xC8258, v);
        (void) INREG(0xC8258);
        printf ("set backlight to %d%%\n", v * 100 / max);
    }