如果一些主板在关机之后电源不是自动关闭，需要手动关闭电源，请在grub里加上：

引用:

#boot=/dev/sda
default=0
timeout=5
splashimage=(hd0,7)/boot/grub/splash.xpm.gz
hiddenmenu
title Fedora (2.6.23.1-42.fc8)
    root (hd0,7)
    kernel /boot/vmlinuz-2.6.23.1-42.fc8 ro root=LABEL=/1234 rhgb quiet acpi=force
    initrd /boot/initrd-2.6.23.1-42.fc8.img

引用:

void __init setup_arch(char **cmdline_p)
{
    unsigned long max_low_pfn;
    paravirt_post_allocator_init();
    dmi_scan_machine();
}

引用:

static int __init blacklist_by_year(void)
{
    int year = dmi_get_year(DMI_BIOS_DATE);
    /* Doesn't exist? Likely an old system */
    if (year == -1) {
        printk(KERN_ERR PREFIX "no DMI BIOS year, "
            "acpi=force is required to enable ACPI\n" );
        return 1;
    }
    /* 0? Likely a buggy new BIOS */
    if (year == 0) {
        printk(KERN_ERR PREFIX "DMI BIOS year==0, "
            "assuming ACPI-capable machine\n" );
        return 0;
    }
    if (year < CONFIG_ACPI_BLACKLIST_YEAR) {
        printk(KERN_ERR PREFIX "BIOS age (%d) fails cutoff (%d), "
               "acpi=force is required to enable ACPI\n",
               year, CONFIG_ACPI_BLACKLIST_YEAR);
        return 1;
    }
    return 0;
}