headless console USB-to-USB

F

fwabi9

Hi all,

I use an HP Pavilion laptop without screen (torn off) as a headless home server.
I access it either on the console, plugging in an external VGA monitor, or via ssh.
Lately I got locked out because: 1. i915kms was deprecated and blacklisted in /boot/loader.conf, 2. I messed up with pf.conf.
Which got me thinking:

would it be possible to connect another PC to one of the USB ports and access the console ?

I read about a few potential trails (1), and suspect it might be possible to use 2 USB-to-Serial cables + 1 Null-modem, as USB-Serial-NullCable-Serial-USB. I would be interested to hear about experiences with such a setup.

Cheers

(1)
www.freebsd.org

Chapter 28. USB Device Mode / USB OTG

This chapter covers the use of USB Device Mode and USB On The Go (USB OTG) in FreeBSD
www.freebsd.org www.freebsd.org
www.freebsd.org

Chapter 29. Serial Communications

This chapter covers some of the ways serial communications can be used on FreeBSD
www.freebsd.org www.freebsd.org
 
Theoretically you should be able to boot in single user mode and attach the VGA monitor, or boot from an installation USB device or CD-ROM. Have you tried that?
 
roccobaroccoSC thanks for your suggestions.

boot in single user mode and attach the VGA monitor
Click to expand...
how can I do that without any monitor and thus without seeing anything ?
boot from an installation USB device
Click to expand...
I tried that with a modified memstick installer: enabling i915kms in /boot/loader.conf which failed. I wasn't aware that the module was blacklisted, so at this point I removed the hard drive and mounted it to another host. I agree this should work though if I'd override module_blacklist or install the i915kms package and and enable it in /etc/rc.conf in the installer. BTW I did exactly that afterwards on the headless server and it works. But I'm missing early boot messages.

I'm not sure these workarounds would help me solving ZFS issues at boot though, or debug my pf rules live.
 
When the computer starts, there is the boot menu. Try to restart it and press 3 .. 3 .. 3 .. 3 .. 3. At some point you should be somewhere in the boot menu. The VGA monitor should be showing some kind of signal.
Press Backspace to clear the unnecessary 3-s and then type "boot -s".
Sorry, it's quite a tricky situation.

Also, there is another workaround but it requires meddling with the hardware.
Unscrew your hard disk and insert it into another machine. Then boot from a rescue/install medium, mount the HDD and modify your loader.conf.
 
You must log in or register to reply here.
Back
Top