Best posts made by davidjryan

@chrishamm
Thanks for verifying that that was a legitimate error/concern.
By default, does 3.5-rc.1 have large SPI transmissions right off the get-go but 3.4.6 does not? Perhaps that's why 3.4.6 was connecting but not faulting out like 3.5-rc.1?

After further testing:
For Bullseye (Deb 11), this works:

echo "options spidev bufsiz=8192" | sudo tee /etc/modprobe.d/spidev.conf 

For Bookworm (Deb 12), it does not.

Instead, I had to add:

spidev.bufsiz=8192

to the end of

/boot/cmdline.txt

After a reboot, when I:

cat /sys/module/spidev/parameters/bufsiz

I get 8192 and DWC now connects to the 6HC with 3.5-rc.1 in SBC mode.

I know we are probably an early adopter of Bookworm on the Pi w/Duet SBC so I'll report out anything else I run into. We'll be exercising our system heavily over the next few weeks.

Update: 10-23-2024

After tabling this issue for the past couple of months, we had to revisit it when we performed a major upgrade to our system that caused the issue to come back in full force to the point where our "automatic" workaround (basically, detection of the issue and software reset) wouldn't work anymore.

We replaced a lot of our 24V hardware with new versions of the same devices and went to different, dual 24V power supplies as well.

After the upgrade, we ran into the disconnection issue almost immediately when trying to run the equipment. We would get tens, almost hundreds of TfrRdy pin glitches in matter of seconds and the Pi/Duet would disconnect within 30s. We disconnected one 24V device at a time and ran some tests until we found that a brushed 24V/2A vacuum pump was putting out excessive noise on the 24V wire which was feeding back to the Pi/Duet. We put a capacitor across the pump's terminals and the TfrRdy pin glitches went to 0. We've been running for a couple of days now and we haven't had a single disconnection between the Pi and Duet.

It looks like our problem was excessive noise generated by poor component selection/sourcing. We tested the other pumps and devices on the system and we are seeing varying amounts of noise but none to the extent of that one particular vacuum pump.

I'll mark this one as solved!

@droftarts Thanks for the update.

I tried the M997 S2 F"unstable" method but the update kept hanging while updating duetcontrolserver (around 89%). It did update the boards to 3.6.0-beta2, just not duetcontrolserver so I kept getting incompatible firmware messages. I had to use the "manual" update method to revert back to 3.5.3 and noticed the potential documentation issue. I'm going to run some more tests to see if the M997 issue is repeatable and I'll create a new thread under Beta firmware if it is. This is all on my testbench, so no harm, no foul.

@Falcounet That did it, thanks!
I had performed:
sudo apt install python3-dsf-python
but didn't include the snippet of that in my post. I guess it didn't matter since I had the older version of dsf-python installed. I do install that version via a script when setting up the Pi/Duet "out of the box". I'll update my script to use python3-dsf-python instead.

Thanks again!