[Pkg-raspi-maintainers] Bug#976118: python3-gpiozero: fails to work with the RPI 4 (on the Debian kernel)

[Lucas Nussbaum]

Package: python3-gpiozero
Version: 1.4.1-1.1
Severity: normal

Dear Maintainer,

gpiozero fails to work with the Debian kernel (as opposed to the
raspberry pi foundation one).

With version 1.4.1, I get:

Traceback (most recent call last):
  File "t2.py", line 4, in <module>
    led = LED(4)
  File "/usr/lib/python3/dist-packages/gpiozero/devices.py", line 95, in __call__
    self = super(GPIOMeta, cls).__call__(*args, **kwargs)
  File "/usr/lib/python3/dist-packages/gpiozero/output_devices.py", line 141, in __init__
    pin, active_high, initial_value, pin_factory=pin_factory
  File "/usr/lib/python3/dist-packages/gpiozero/output_devices.py", line 47, in __init__
    super(OutputDevice, self).__init__(pin, pin_factory=pin_factory)
  File "/usr/lib/python3/dist-packages/gpiozero/mixins.py", line 69, in __init__
    super(SourceMixin, self).__init__(*args, **kwargs)
  File "/usr/lib/python3/dist-packages/gpiozero/devices.py", line 375, in __init__
    pin = self.pin_factory.pin(pin)
  File "/usr/lib/python3/dist-packages/gpiozero/pins/pi.py", line 73, in pin
    pin = self.pin_class(self, n)
  File "/usr/lib/python3/dist-packages/gpiozero/pins/rpigpio.py", line 94, in __init__
    super(RPiGPIOPin, self).__init__(factory, number)
  File "/usr/lib/python3/dist-packages/gpiozero/pins/pi.py", line 241, in __init__
    factory.pi_info.physical_pin(repr(self))
  File "/usr/lib/python3/dist-packages/gpiozero/pins/__init__.py", line 130, in <lambda>
    lambda self: self._get_pi_info(),
  File "/usr/lib/python3/dist-packages/gpiozero/pins/pi.py", line 90, in _get_pi_info
    self._info = pi_info(self._get_revision())
  File "/usr/lib/python3/dist-packages/gpiozero/pins/local.py", line 67, in _get_revision
    raise PinUnknownPi('unable to locate Pi revision in /proc/cpuinfo')
gpiozero.exc.PinUnknownPi: unable to locate Pi revision in /proc/cpuinfo


I tried upgrading to the current upstream git tree.
I run in another issue, which is caused by missing support in RPi.GPIO:

Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/gpiozero/pins/pi.py", line 109, in pin
    pin = self.pins[n]
KeyError: 4

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "t2.py", line 4, in <module>
    led = LED(4)
  File "/usr/lib/python3/dist-packages/gpiozero/devices.py", line 131, in __call__
    self = super(GPIOMeta, cls).__call__(*args, **kwargs)
  File "/usr/lib/python3/dist-packages/gpiozero/output_devices.py", line 217, in __init__
    pin, active_high, initial_value, pin_factory=pin_factory
  File "/usr/lib/python3/dist-packages/gpiozero/output_devices.py", line 99, in __init__
    super(OutputDevice, self).__init__(pin, pin_factory=pin_factory)
  File "/usr/lib/python3/dist-packages/gpiozero/mixins.py", line 106, in __init__
    super(SourceMixin, self).__init__(*args, **kwargs)
  File "/usr/lib/python3/dist-packages/gpiozero/devices.py", line 545, in __init__
    pin = self.pin_factory.pin(pin)
  File "/usr/lib/python3/dist-packages/gpiozero/pins/pi.py", line 111, in pin
    pin = self.pin_class(self, n)
  File "/usr/lib/python3/dist-packages/gpiozero/pins/rpigpio.py", line 132, in __init__
    GPIO.setup(self.number, GPIO.IN, self.GPIO_PULL_UPS[self._pull])
RuntimeError: Not running on a RPi!

That's due to missing support in RPi.GPIO (see #976114 and
https://sourceforge.net/p/raspberry-gpio-python/tickets/191/ ).

After fixing RPi.GPIO with the dirty patch I provided in the upstream ticket, gpiozero works fine.

However, gpiozero should also work without RPi.GPIO (see the native pin
factory in the code). Without RPi.GPIO, I get:

/usr/lib/python3/dist-packages/gpiozero/devices.py:289: PinFactoryFallback: Falling back from rpigpio: No module named 'RPi'
  'Falling back from %s: %s' % (name, str(e))))
/usr/lib/python3/dist-packages/gpiozero/devices.py:289: PinFactoryFallback: Falling back from rpio: No module named 'RPIO'
  'Falling back from %s: %s' % (name, str(e))))
/usr/lib/python3/dist-packages/gpiozero/devices.py:289: PinFactoryFallback: Falling back from pigpio: No module named 'pigpio'
  'Falling back from %s: %s' % (name, str(e))))
/usr/lib/python3/dist-packages/gpiozero/devices.py:289: PinFactoryFallback: Falling back from native: [Errno 1] Operation not permitted
  'Falling back from %s: %s' % (name, str(e))))
Traceback (most recent call last):
  File "t2.py", line 4, in <module>
    led = LED(4)
  File "/usr/lib/python3/dist-packages/gpiozero/devices.py", line 131, in __call__
    self = super(GPIOMeta, cls).__call__(*args, **kwargs)
  File "/usr/lib/python3/dist-packages/gpiozero/output_devices.py", line 217, in __init__
    pin, active_high, initial_value, pin_factory=pin_factory
  File "/usr/lib/python3/dist-packages/gpiozero/output_devices.py", line 99, in __init__
    super(OutputDevice, self).__init__(pin, pin_factory=pin_factory)
  File "/usr/lib/python3/dist-packages/gpiozero/mixins.py", line 106, in __init__
    super(SourceMixin, self).__init__(*args, **kwargs)
  File "/usr/lib/python3/dist-packages/gpiozero/devices.py", line 536, in __init__
    super(GPIODevice, self).__init__(**kwargs)
  File "/usr/lib/python3/dist-packages/gpiozero/devices.py", line 250, in __init__
    Device.pin_factory = Device._default_pin_factory()
  File "/usr/lib/python3/dist-packages/gpiozero/devices.py", line 290, in _default_pin_factory
    raise BadPinFactory('Unable to load any default pin factory!')
gpiozero.exc.BadPinFactory: Unable to load any default pin factory!


This is known upstream, and there's a PR in progress:
https://github.com/gpiozero/gpiozero/pull/900

Lucas



-- System Information:
Debian Release: 10.6
  APT prefers stable
  APT policy: (990, 'stable')
Architecture: arm64 (aarch64)

Kernel: Linux 5.8.0-0.bpo.2-arm64 (SMP w/4 CPU cores)
Kernel taint flags: TAINT_CRAP
Locale: LANG=en_DK.UTF-8, LC_CTYPE=C.UTF-8 (charmap=locale: Cannot set LC_MESSAGES to default locale: No such file or directory
locale: Cannot set LC_ALL to default locale: No such file or directory
UTF-8), LANGUAGE=en_DK.UTF-8 (charmap=locale: Cannot set LC_MESSAGES to default locale: No such file or directory
locale: Cannot set LC_ALL to default locale: No such file or directory
UTF-8)
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages python3-gpiozero depends on:
ii  python3           3.7.3-1
ii  python3-rpi.gpio  0.7.0-0.2

python3-gpiozero recommends no packages.

Versions of packages python3-gpiozero suggests:
pn  python-pigpio  <none>