Hi

I was trying to debug a wayland problem so I tried to change the console on my PC build from tty0 to ttyUSB0 which is a USB serial port. I am using a machine without PC serial.

I am running busybox and I cannot get the output to go to this console. If I change cmd line in the kernel to exclude tty0 I get a cannot initialize console error.

Is there an easy way to run see the output from the serial port, something like tee, with busybox only.

Busybox is running as init at this stage.

Hi,

Normally you would use the kernel console parameter to redirect the output.
Look here for more information.

Cheers,

There is also an ubuntu page and the kernel documentation. I haven't had a look at the source but the following command line works:
console=tty0 console=ttyUSB0,115200n8
According to the Documentation in the source tree the last console paramater is used as the default should the others not be specified. I suspect that this is incorrect.

If I put the ttyUSB0 first and don't have the PL2303 plugged in I get a panic/oops. If I have it plugged in while it is first, I see a line cannot open console. I have craeted the tty0 ttyUSB0 console devices in the image with the same major and minors that udev gives them. I do get output.

If I use the command line as specified I see output on both consoles but I can only enter commands from the keyboard as I don't have a video driver loaded yet. But I do get the kernel traces on the serial port. So I would also like to be able to redirect the output from the console (ie process #1's fds 1 & 2) to the USB device. So I think that I need something like tee that will take the output and write it to two fds. Would that work?