[BUG + FIX] USE_USB_COMPOSITE on STM32F103RC while using serial causes firmware to freeze

[Loafdude]

Bug Description

Using SKR 1.2 Mini E3 (STM32F103RC) on Ender 3 Pro.
When using STM32F103RC_bigtree_512K everything is OK
When using STM32F103RC_bigtree_512K_USB firmware can freeze and cause overheat.
Using 2.0.x-bugfix branch

config files attached.

Steps to Reproduce

1. Flash Merlin 2.0.x-bugfix using enviroment STM32F103RC_bigtree_512K_USB
2. Connect USB (tried with and without 5v supply from USB host)
3. Connect to Serial Port (I used Pronterface)
4. Issue a command (I used M303 S240 C10 to start PID autotune)
5. Serial will perform normally for a time (60sec perhaps)
6. LCD will freeze, Serial traffic will stop. Hotend continues to heat.
7. If you reconnect to the serial port the LCD display will start working and serial will respond again. It will freeze up again around 60 sec later. You can repeat this process to keep the firmware running

I have overtemp protection on which is still functional and causes alarm on the printer.
Switching to non USE_USB_COMPOSITE environment appears to be OK

Loafdude Config.zip

[reloxx13]

can confirm, serial disconnects while pidtuning, but the pidtuning completes.

but other commands work fine.

[Loafdude]

Tried disabled emulated EEPROM (EEPROM.DAT) but still get freezing when running M303 S240 C10.

[tatusah]

Here @Loafdude I included those PIDs to the compiled firmware. It's the latest bugfix. If it still freezes on your setup then it I guess it might be some random hardware issue.
Marlin_conf_plus_bin.zip

[tatusah]

For me PID tuning seems to work alright also in Octoprint tried 240C and 200C with 10 iterations. Is the issue happening to you every time you try PID tuning?

[Loafdude]

Fails with your firmware.bin as well.
Yes it fails consistently every time.

I think I have narrowed it down though!
I believe it is a conflict between the storage and serial devices on the STM32F103RC.
If I disable the storage device in device manager in windows and only use serial it works!

I suspect you are not seeing this error because you are using Octoprint.
That could be because of a few reasons

• Octoprint is not mounting the fat32 volume
• Windows is polling the filesystem and linux is not and therefor it does not cause a crash
• Linux USB stack is not triggering the error

I bet if you used a windows machine and did the same command it would freeze.

[tatusah]

I have tested it also on Windows using Repetier and Printrun (pronterface), working with both of them. What I investigated about similar kind of issues the recommended solutions varied mostly between trying different baud rates and different USB cables. Seems like a quite wicked problem as it's difficult to locate if it's Marlin, hardware, drivers or the combination of the all.

[Loafdude]

I'll try a linux machine too. I've tried two windows machines with different platforms and different cables so it's def not hub or host USB controller related. I really don't think it is a host / host hardware issue.

The SD card becomes unresponsive when serial is in use too. Perhaps it is a multitasking issue on the STM32. It runs serial for a while then goes to run mass storage and no serial cpu time causes merlin to freeze because serial is part of it's program loop. just speculating tho

[tatusah]

Have you tried what happens if you try PID tuning without SD card or by enabling NO_SD_HOST_DRIVE which does kind of negate the USB composite, but might help narrowing down the issue?

[tpruvot]

USE_USB_COMPOSITE is not marlin related, but a STM32 (experimental) framework feature...

[boelle]

@tpruvot so this is not marlin related after all?

[Loafdude]

It is difficult for me to provide a bug report upstream to the framework as I am not familiar enough with Marlin codebase to provide accurate information. I'm happy to work with someone to test and provide the needed feedback in a timely fashion.
Regardless I can still reproduce freezing consistently and it has been confirmed by @reloxx13 but does not affect all SKR 1.2 E3 Mini users apparently.
This does have the potential for thermal runaway if protections are not turned on. (My unit gets heating error while frozen).
At this point I cannot reliably use serial interface while USE_USB_COMPOSITE is in place.

[Phisik]

Can confirm this issue for SKR E3 v1.2 with the latest Marlin 2.0.1. During PID tuning USB version freezes but the machine keeps(!) heating resulting in runaway error on next boot if I delay with reset! This is how it works under Win10 in Cura & Simplify3D.

However in linux environment things may run different. Only serial connection freezes, but PID tuning finishes ok. It seems the USB device gets reset every ~30 seconds....

...
Jan 17 18:31:13 octopi kernel: usb 1-1.2: reset full-speed USB device number 12 using xhci_hcd
Jan 17 18:31:14 octopi kernel: cdc_acm 1-1.2:1.1: ttyACM0: USB ACM device
Jan 17 18:31:44 octopi kernel: usb 1-1.2: reset full-speed USB device number 12 using xhci_hcd
Jan 17 18:31:44 octopi kernel: cdc_acm 1-1.2:1.1: ttyACM0: USB ACM device
Jan 17 18:32:15 octopi kernel: usb 1-1.2: reset full-speed USB device number 12 using xhci_hcd
Jan 17 18:32:15 octopi kernel: cdc_acm 1-1.2:1.1: ttyACM0: USB ACM device
Jan 17 18:32:46 octopi kernel: usb 1-1.2: reset full-speed USB device number 12 using xhci_hcd
Jan 17 18:32:46 octopi kernel: cdc_acm 1-1.2:1.1: ttyACM0: USB ACM device
...

[tpruvot]

A good start would be to find a way to toggle it by software, but without reseting the whole composite stack (which cut serial connection too)... maybe a simple "ignore USB SD calls" boolean could help.... I believe win10 is doing something weird on disk detection... every fast usb keys are slow to be available in win10...