GPIO Module Error - only runs on raspberry pi

lindsay

RP 4 2GB
Retropie 4.85
Linux 5.10.103 Raspian GNU/Linux 10 (buster)
Official power supply

Hi all,
Ever since I upgraded to Pi 4 GPIO doesn't work.

Error: This module can only be run on a Raspberry Pi.

Importing the gpio module in interactive python 2 and 3 produces the above error.

python3
>>> import RPi.GPIO as GPIO

I have updated and reinstalled it according to several articles online and there is no fix for my system.

sudo apt-get install python3-rpi.gpio 
already newest version 0.7.0.0.1

sudo apt install raspi.gpio
already newest version (0.20191001)
raspi-gpio set to manually installed

So it's a bit of a mess now and power button scripts seem to rely on gpio working. I had this working fine on my previous 3B+.
Any ideas
Thank you

mitu

Can you post the script that produces the error you mentioned ? How did install RetroPie - did you use a clean Pi4 image or did you use your old RPI 3B+ image ?

lindsay

@mitu I used the latest img file from retro pie.

I can give you the script, but it didn't work, so I investigated further by running python3 from the command line as shown above and started testing each line so I could see if there was an error. And the import line produced the error.

Here is the shutdown.py script if you still want it, but I don't think it's relevant because we know which line doesn't work:

#!/usr/bin/python

import RPi.GPIO as GPIO

import time

import subprocess


# we will use the pin numbering to match the pins on the Pi, instead of the 

# GPIO pin outs (makes it easier to keep track of things)
GPIO.setmode(GPIO.BOARD)  

# use the same pin that is used for the reset button (one button to rule them all!)

GPIO.setup(5, GPIO.IN, pull_up_down = GPIO.PUD_UP)  
oldButtonState1 = True
while True:

    #grab the current button state

    buttonState1 = GPIO.input(5)



    # check to see if button has been pushed

    if buttonState1 != oldButtonState1 and buttonState1 == False:

      subprocess.call("shutdown -h now", shell=True, 

        stdout=subprocess.PIPE, stderr=subprocess.PIPE)

      oldButtonState1 = buttonState1

    time.sleep(.1)

As far as I know, all the scripts import RPi.GPIO so none of them can possibly work if the import statement doesn't work.

The question is why can't I import a library on the pi 4 that was designed specifically for the pi.

mitu

@lindsay said in GPIO Module Error - only runs on raspberry pi:

I used the latest img file from retro pie.

ok, so it's a new installation.

I can give you the script, but it didn't work, so I investigated further by running python3 from the command line as shown above and started testing each line so I could see if there was an error. And the import line produced the error.
[..]

I don't have a Pi4 at hand at this moment, but the import command works without issue on a PI3 using a stock (updated) RetroPie image. Regardless, the python3-rpi.gpio is provided by the OS (Raspberry Pi OS Lite) and it should work out-of-the-box, without any further installations. RetroPie doesn't add or remove anything related to the GPIO Python module contained in the package.

I can try the import statement (and the script) when I have a Pi4 with RetroPie at hand, but I'm not expecting to fail.

mitu

OK, so I checked on my Pi4 with RetroPie and cannot reproduce the error. The python3-rpi.gpio was not installed though on the system, so I installed it and then ran the import command without issues.
Running the script also doesn't yield the error you posted (although it complains about A physical pull up resistor is fitted on this channel! on line 17, it doesn't terminate).

The Python3 module version installed is (almost) the same:

apt show python3-rpi.gpio
Package: python3-rpi.gpio
Version: 0.7.0-0.1~bpo10+4
Priority: optional
Section: python
Source: rpi.gpio
Maintainer: Debian Raspberry Pi Maintainers <pkg-raspi-maintainers@lists.alioth.debian.org>
Installed-Size: 68.6 kB
Depends: rpi.gpio-common (= 0.7.0-0.1~bpo10+4), python3 (<< 3.8), python3 (>= 3.7~), python3:any, libc6 (>= 2.7)
Homepage: http://sourceforge.net/projects/raspberry-gpio-python/
Download-Size: 20.7 kB
APT-Manual-Installed: yes
APT-Sources: http://archive.raspberrypi.org/debian buster/main armhf Packages

Are you sure you haven't manually installed manually some older version of Python (2 or3) module, one that does not supported the Pi4 model ? Try doing an update of the system and the installed OS packages so the latest version of the package is installed.

lindsay

@mitu said in GPIO Module Error - only runs on raspberry pi:

version installed is (almost) the same:

Thank you mitu.
I read that the Pi 4 has pull-up resistors on pins 2 and 3 for IIC protocol. But if this library is specifically for Raspberry Pi, it does make me wonder why it would complain..

It may well be the case that I installed something outdated by accident, Python you think? I mean, the version of Python really shouldn't matter as long as it's 2.7 for python 2 and 3.5+ for python 3.

Yeah, I will do a backup and try running updates. Thank you for your help.

lindsay

I am running Python 3.7.3

mitu

@lindsay said in GPIO Module Error - only runs on raspberry pi:

It may well be the case that I installed something outdated by accident, Python you think? I mean, the version of Python really shouldn't matter as long as it's 2.7 for python 2 and 3.5+ for python 3.

It's a bit more difficult to install Python itself and overwrite the system's installed one, I was thinking you might have installed an older version of the GPIO Python module, which might explain the error message.