[systemd-devel] Serial console issue.

[Lennart Poettering]

On Di, 07.11.17 16:48, Yann Le Mouel (yann at lemouel.ch) wrote:

> Hello,
> 
>  
> 
> I've been following your guidelines (serial-console.html) about serial
> console. I'm testing this function via AMT on Intel NUC'S on Centos 7.4. I'm
> using AMTTERM package for the test.
> 
>  
> 
> I managed to get the serial working until certain point, as below, I can see
> the boot which is really fast until set hostname, and then so slow, lines by
> lines,

Normally, it should suffice to set the kernel console to ttyS0 (or
whichever device you use) via the kernel cmdline. The rest should then
happen fully automatically, as systemd contains an automatic genreator
which uses this to also invoke a serial getty on the same serial port
you used for the console.

Note that if multiple processes fight for console ownership you will
experience all kinds of problems. The log you pasted shows that you
have getty at .service and serial-getty at .service fighting for access to
ttyS1. That's already indication of a problem, and most likely
happened because you enabled these units manually? First of all, that
should not be necessary, as things should work automatically anyway,
as mentioned above. Moreover, enable "getty at .service" (as opposed to
serial-getty at .service) is incorrect anyway, as that unit is for VTs
only, not for serial ttys.

Hence, I am not entirely sure what changes you made. My recommendation
would be to undo them all, and just set console= on the kernel
cmdline, and all should be good.

Lennart

-- 
Lennart Poettering, Red Hat