MAX7219 fails with "error return without exception set"

Type of Raspberry Pi

Raspberry Pi 3B

Linux Kernel version

Linux endeavour 5.4.42-v8+ #1319 SMP PREEMPT Wed May 20 14:18:56 BST 2020 aarch64 GNU/Linux

Yes I’m running a 64-bit kernel and the very latest updated with sudo rpi-update. I’m quite happy to switch to running 5.4.42-v7 if you need that.

Expected behaviour

Your matrix demo program runs and does the usual stuff

Actual behaviour

I can get the same effect with python2 or python3 (I got the python3 version installed today with sudo pip3 ... to see if it made a different (it didn’t)).

pi@endeavour:~/python$ ./matrix_demo.py
Traceback (most recent call last):
  File "./matrix_demo.py", line 120, in <module>
    demo(args.cascaded, args.block_orientation, args.rotate)
  File "./matrix_demo.py", line 20, in demo
    serial = spi(port=0, device=0, gpio=noop())
  File "/usr/local/lib/python2.7/dist-packages/luma/core/interface/serial.py", line 281, in __init__
    self._spi.cshigh = cs_high
SystemError: error return without exception set
pi@endeavour:~/python$

I’ve hacked a very ugly C program to drive the matrix on the v8 5.4.42 kernel and that worked OK. You can have a copy of that if you need it (you won’t).

[DougieLawson]

I think this one is fixed with the 5.4.51 kernel that the RPF/RPTL folks released today.

[DougieLawson]

It’s still happening with the 5.4.47 kernel.