Linux 系统关机后电源无法关闭的解决办法

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

只要加上红色的那句话就可以正常关机。具体原因分析如下：

Kernel 起来以后会执行 arch/i386/kernel/setup.c

引用:

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

Dmi_scan_machine() 会从BIOS 里面获取DMI 支持的信息。ACPI driver 会通过

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;
}