Serial console not taking user inputs

[Rajesh]

Hi,

We encounter a problem where serial console shows up the boot logs, but not taking any user inputs. Any possible reasons?

We see the UART driver initialized properly during boot, but still user inputs are not accepted.

/boot/loader.conf:

comconsole_speed=115200
comconsole_port=0x3F8
console=comconsole

Let me know if you need any details.

Thanks,
Rajesh.

 

[Phishfry]

These settings work for me:
/boot/loader.conf

boot_multicons="YES"
boot_serial="YES"
comconsole_speed="115200"
console="comconsole,vidconsole"

Taken from this document

Chapter 29. Serial Communications

This chapter covers some of the ways serial communications can be used on FreeBSD

www.freebsd.org

If you happen to be using EFI than you need to change one option;

boot_multicons="YES"
boot_serial="YES"
comconsole_speed="115200"
console="comconsole,EFI"

 

[Rajesh]

Thanks for the response Phishfry

Still no luck with the input. With just "boot_multicons", I am seeing the boot logs in Video console and serial console. So, is that "boot_serial" and adding "EFI" to console really needed?

Suspecting any issue with the UART driver. Any idea how serial console and UART driver are related? Because output to serial console works (boot logs), but input is not working. So wondering if something is screwed up with UART driver?

 

[Phishfry]

How about in your BIOS under serial redirection. Are you using ASCI or VT100 ?
If your BIOS does not support serial redirection you can ignore this.

 

[SirDice]

Suspecting any issue with the UART driver. Any idea how serial console and UART driver are related? Because output to serial console works (boot logs), but input is not working. So wondering if something is screwed up with UART driver?

A more likely scenario is that your null-modem cable has a broken wire. The UART driver has been around for years, the actual hardware hasn't changed, so it's unlikely that it's a bug in the driver. Not impossible of course, just highly unlikely. A null-modem cable has, at least, 3 wires, one ground, one transmit and one receive. You can see how it easy it is to only have one way communication if one of the wires breaks. And null-modem cables break all the time, mine do (cheap or home made ones).

It does beg the question, how are you connected to the serial console?