Re: How to enable output to serial console at run-time?

[Alan Cox]

On Thu, 2 Nov 2017 20:01:07 +0100
Paul Menzel <pmenzel+linux-ser...@molgen.mpg.de> wrote:

> Dear Greg,
> 
> 
> Am 02.11.2017 um 17:53 schrieb Greg KH:
> > On Thu, Nov 02, 2017 at 04:39:36PM +0100, Paul Menzel wrote:  
> 
> >> If I want to output the Linux kernel messages to the serial console, but 
> >> the
> >> `console=ttyS…` line is missing on the Linux command line, is there a way 
> >> to
> >> activate that during run-time by, for example, using the sysfs interface?  
> > 
> > Why not change the command line to enable it properly?  
> 
> Sometimes it’s not possible or very inconvenient to reboot the system.

Try "man 2 ioctl_tty"


Alan