Linux 串口终端设置

default=0
timeout=10

#这2行指定 Grub 的 Serial 重定向的参数， 9600，n81
serial --unit=0 --speed=9600 --word=8 --parity=no --stop=1
terminal --timeout=10 serial console

title Linux
 root (hd0,0)
 # console 内核参数指定console设备，可以同时指定多个console,
 # 但是不能同时指定相同类型的console，例如：ttyS0 和 ttyS1。
 # 最后面的一个将被认定为 /dev/console 设备。
 kernel /boot/vmlinuz root=/dev/hda6 console=tty0 console=ttyS0,9600n8
 initrd /boot/initrd

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加入行在/etc/inittab：

其中 115200,9600 参数指定如果115200失败，则降速到9600。

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参考：

Figure 5-2. Recommended kernel parameters, PCs with video card

console=tty0 console=ttyS0,9600n8

Kernel messages will appear on both the first virtual terminal and the serial port. Messages from the init system and the system logger will appear only on the first serial port. This can be slightly confusing when looking at the attached monitor: the machine will appear to boot and then hang. Don't panic, the init system has started but is now printing messages to the serial port but is printing nothing to the screen. If a getty has been configured then a login: prompt will eventually appear on the attached monitor.