stm32f407 discovery serial example does not work

[niclashoyer]

Hi,

I tried to run the serial example on my stm32f407 discovery board: https://github.com/Disasm/usb-otg-workspace/blob/master/example-f407-board/examples/serial.rs

The code runs fine so far, the device enumerates:

$ lsusb
Bus 004 Device 008: ID 0483:3748 STMicroelectronics ST-LINK/V2
Bus 002 Device 012: ID 16c0:27dd Van Ooijen Technische Informatica CDC-ACM class devices (modems)
…

But it does not send/receive any characters on /dev/ttyACM0. I already tried to investigate it, as there is no error so far. The only thing that I see is that it never actually receives data. I already tried several clients (screen, tio, minicom), to no avail. I also uninstalled ModemManager, just in case.

Using usbmon and wireshark I see that the device connects successfully, but then just stops communicating after the SET LINE CODING Request:

Full wireshark dump: usb.pcapng.gz

Is there any way I could debug this further?

[niclashoyer]

Just tested on a different computer and it worked there, strange. dmesg output was also a bit different. I'll try to dump usb messages there and compare them.

[Disasm]

A silly question: a you running a release build of a firmware?

[niclashoyer]

yes and the firmware was identical (actually flashed it on the non-working computer and just plugged it into the other computer)

edit: flashed using this command:

cargo run --release --example serial

[niclashoyer]

Ok, here is the dump of the communication from the working computer:

usb.pcapng.gz

As far as I can see the communication is the same until URB_CONTROL out and then it just starts communicating (I just pressed abc):

I already tested on another computer and it also worked there, so I think it must be something with the OS, but I don't know how to proceed from here.

I think this can be closed for now.