Potential tty symlink error in am335x-debian-11.5-minimal-armhf-2022-11-01-2gb.img.xz

General Discussion
1

With bone-debian-10.13-iot-armhf-2022-11-01-4gb.img.xz from Debian 10.x (Buster) - Monthly Snapshots, there are symlinks present for /dev/ttyO*:

debian@beaglebone:~$ ls -l /dev/ttyO*
lrwxrwxrwx 1 root root 5 Nov  8 22:27 /dev/ttyO0 -> ttyS0
lrwxrwxrwx 1 root root 5 Nov  8 22:27 /dev/ttyO1 -> ttyS1
lrwxrwxrwx 1 root root 5 Nov  8 22:27 /dev/ttyO2 -> ttyS2
lrwxrwxrwx 1 root root 5 Nov  8 22:27 /dev/ttyO3 -> ttyS3
lrwxrwxrwx 1 root root 5 Nov  8 22:27 /dev/ttyO4 -> ttyS4
lrwxrwxrwx 1 root root 5 Nov  8 22:27 /dev/ttyO5 -> ttyS5

With am335x-debian-11.5-minimal-armhf-2022-11-01-2gb.img.xz from Debian 11.x (Bullseye) - Monthly Snapshots, these symlinks are not present:

debian@beaglebone:~$ ls /dev/tty | grep "/dev/ttyO"

Why were these symlinks around in Debian 10? Are they supposed to still be around in Debian 11?

Also, I believe the default debian user should be added to the tty group, it doesn’t seem to have taken place by default.

2

It should be set as dialout

This has a long history of back and forth… Originally, ttySx was used, then in 3.8.x ttyOx, then eventually back to ttySx… Debian 11.x (Bullseye)'s glibc doesn’t support 3.8.x.

Regards,

1 Like
3

Thank you for the response! I apologize but I have a few clarifying questions below:

It should be set as dialout

What is “it” here? Is it the debian user? The debian user is a member of dialout already.

Also, to confirm, does the dialout group have access to the tty’s?

This has a long history of back and forth… Originally, ttySx was used, then in 3.8.x ttyOx, then eventually back to ttySx… Debian 11.x (Bullseye)'s glibc doesn’t support 3.8.x.

So to interpret this, you’re saying these symlinks should not be present in Debian 11, yes?

I ask because the we were using /dev/ttyO1. Now I am thinking we should switch to using ttyS1, can you confirm this is the right move?

4

Due to this thread, I’ll add them back… For future, you probably would want to use ttySx from time to time, developers talk about removing the older serial driver completely from mainline…

Regards,

5

Nah no need to add it in! I have already moved us to use ttySx.

All I need to know is that ttyOx is the wrong move moving forward.