Hello all,
I'm trying to add a secondary serial port to my Raspberry Pi 1 Model A for
debugging reasons (I want to repurpose the main UART for `pppd` as an
experiment). Right now, I'm stuck on trying to spawn a getty on the USB
serial port.
According to dmseg, my USB-to-serial device is a Prolific device:
```
ucom0 at uplcom0
uplcom0 at uhub0 port 1
uplcom0: Prolific Technology Inc. (0x67b) USB 2.0 To COM Device (0x2303),
rev 1.10/3.00, addr 2
```
According to `man uplcom` and `man ucom`, `ucom` devices are treated as
`ttys` and are available under `/dev/ttyU?`, where I presume `?` matches the
number assigned to `ucom?`. So, using the above `dmesg` output, I add an
entry to `/etc/ttys`, expecting it to be picked up on reboot:
```
ttyU0 "/usr/libexec/getty default" vt100 on secure
```
However, this change had no effect and I didn't see any output on the system
attached at the other end of the USB serial port upon rebooting. At this
point I figured it's possible that the baud rate is incorrect, but I figured
I should debug from a root shell first.
However, no matter which arguments I invoke the getty program_, getty
_insists_ on using the main console, to dump input and output. This leads to
fun things that I had no idea were possible like, for example (when invoking
using `/usr/libexec/getty default ttyU0`):
* Getting a login prompt printed over the UART associated with `console`
that says "(`ttyU0`)", when `ttyU0` should be associated with the USB serial
port.
* Logging into said login prompt, invoking `tty` command, and the output
saying my current tty is a psuedoterminal: `/dev/pts/0`
At this point I'm stumped. What would cause me to have the above conditions?
And what is the proper command I should use from a root shell (after logging
in over `console` UART) to spawn a login prompt over the USB serial port?
As always, thanks all for any help.
Sincerely,
--
William D. Jones
thor0...@comcast.net
