How to change serial port for prinkt

david_8274 · 10-05-2015, 10:26 AM

Hi,

In my system I have two serial ports (uart0 & uart1). Currently my printk() function is using uart0. Now I wish to do printk() on uart1, how would I do it? I tried to look for definition of printk() in the kernel source code, but it's rather hidden and complicated(as I am a Linux newbie).

Thanks,
Wei

smallpond · 10-06-2015, 02:19 PM

printk writes to consoles which are specified on the kernel command line. The default is usually the first UART and the first tty (text screen) but you can add others. Add the param in /boot/grub/grub.conf for grub1. For grub2 edit /etc/default/grub, and then run update-grub. On the system I'm logged into the consoles are specified as:

Code:

console=tty0 console=ttyS0,115200n8