getty prevents serial port usage

[ZL4JY]

Despite disabling the console using raspi-config, getty still takes control of both ttyS0 and ttyAMA0.

Version:

Raspberry Pi OS with desktop
Release date: March 15th 2024
System: 64-bit
Kernel version: 6.6
Debian version: 12 (bookworm)

[ZL4JY]

To test:

Disable console using raspi-config
Follow usual steps to enable ttyS0 or ttyAMA0
Check permissions on /dev/ttyAMA0
sudo chmod 777 /dev/ttyAMA0
Wait 20 seconds and check permissions again

Work around:

sudo systemctl stop serial-getty@ttyAMA0
sudo systemctl mask [email protected]

Repeat the test procedure to confirm permission changes remain unaltered.

[lurch]

Could you clarify which model of Raspberry Pi you'e using please? The serial ports are setup slightly differently on different models of Raspberry Pi https://www.raspberrypi.com/documentation/computers/configuration.html#configure-uarts

[ZL4JY]

RP 5

[lurch]

I'm unable to reproduce this. Could you please give exact reproduction steps? (e.g. what does "Follow usual steps to enable ttyS0 or ttyAMA0" mean?)

Here's what I did (on a fully up-to-date 64-bit Raspberry Pi OS Bookworm image) on a Pi5:

• ran sudo raspi-config
• selected "3 Interface Options"
• selected "I6 Serial Port"
• answered "No" when asked "Would you like a login shell to be accessible over serial?"
• answered "Yes" when asked "Would you like the serial port hardware to be enabled?"
• selected "OK" and "Finish" to exit raspi-config
• rebooted as prompted
• after reboot, ls -l /dev/ttyAMA0 shows the permissions as crw-rw----
• ran the sudo chmod 777 /dev/ttyAMA0 that you suggested
• ls -l /dev/ttyAMA0 now shows the permissions as crwxrwxrwx
• I waited a couple of minutes, and ls -l /dev/ttyAMA0 still shows the permissions as crwxrwxrwx
• systemctl status serial-getty@ttyAMA0 lists the service as both disabled and inactive (dead)