decuser
Posts: 5
Joined: Sun Feb 17, 2013 5:21 pm

Is it normal to not see linux boot messages when connected to rpi (various versions) via serial cable?

Wed Feb 21, 2018 2:18 am

I am connecting to my pi(s) via a prolific 2303 cable and I eventually see a login, but no linux boot messages - I seem to recall being able to see these messages in the past, but I'm not sure now. I even tried rebooting with out disconnecting the cable and sure enough, I see the reboot message and then nothing until the login message:

raspberrypi login: pi
Password:
Last login: Thu Sep 7 16:17:20 UTC 2017 on tty1
Linux raspberrypi 4.9.41+ #1023 Tue Aug 8 15:47:12 BST 2017 armv6l

The programs included with the Debian GNU/Linux system are free software;
the exact distribution terms for each program are described in the
individual files in /usr/share/doc/*/copyright.

Debian GNU/Linux comes with ABSOLUTELY NO WARRANTY, to the extent
permitted by applicable law.
[email protected]:~$ sudo reboot
[ 97.011839] reboot: Restarting system

Raspbian GNU/Linux 9 raspberrypi ttyAMA0
raspberrypi login:

Is it possible to see the boot messages in real time (I know I can see them in retrospect via dmesg)?

Will

jdb
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
Posts: 2161
Joined: Thu Jul 11, 2013 2:37 pm

Re: Is it normal to not see linux boot messages when connected to rpi (various versions) via serial cable?

Wed Feb 21, 2018 2:16 pm

Remove the "quiet" parameter from /boot/cmdline.txt. This will give you kernel messages on the serial console.
Rockets are loud.
https://astro-pi.org


dgordon42
Posts: 764
Joined: Tue Aug 13, 2013 6:55 pm
Location: Dublin, Ireland

Re: Is it normal to not see linux boot messages when connected to rpi (various versions) via serial cable?

Wed Feb 21, 2018 4:36 pm

decuser wrote:I am connecting to my pi(s) via a prolific 2303 cable
I take it that the USB side is connected to the Pi. If so I don't think you can see the boot messages on a connected terminal as the Pi has to boot before the USB ports are up & running. I have tried adding "console=ttyUSB0,9600" to my '/boot/cmdline.txt' file, but I still don't see any boot messages on my old DEC VT320 Terminal which I connect to my Pi with a Prolific PL2303 Serial to USB Converter. with the USB side connected to the Pi.

Hope this helps,
Dave.

EDIT:
@decuser
Sorry, disregard. I was typing when you replied.

Dave.

decuser
Posts: 5
Joined: Sun Feb 17, 2013 5:21 pm

Re: Is it normal to not see linux boot messages when connected to rpi (various versions) via serial cable?

Wed Feb 21, 2018 5:00 pm

@dgordon42, actually, I didn't even consider going the other way with a VT - awesome. I have a sudden urge to go grab a vt and do some pdp sims :).

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