Linux console output on multiple UARTs

Question

My embedded board has 2 UARTs. I want to have console output on both the UARTs.

In kernel/Documentation/console/console.txt it's mentioned that:

you can only define one console per device type (serial, video).

Does this mean I can use only one UART as console? Or, is it possible to redirect the console output to both of these UARTs?

Answer 1

It's possible to achieve that via adding consoles to the kernel command line. For example,console=ttyS0,115200n8 console=ttyS1,57600n8 will add two serial consoles (8250 driver assumed) on ports 0 and 1 (whatever it means on the platform in question). One of them will be so called preferred.

For the details, consult kernel documentation: http://elixir.free-electrons.com/linux/latest/source/Documentation/admin-guide/serial-console.rst