USB CDC fails on F745 when communicating through USB hub.
The USB communication fails when connecting F745 MCU to a USB hub that is connected to a PC. Without the hub it is working normally without any errors. Currently the setup consist of a desktop app that sends something to the MCU and expects a response back. What happens is that the USB read on PC side timeouts while waiting for a response. Problem is that the message is not even received on the MCU and thus nothing is prepared for response, thus the desktop app timeouts. Looking at Wireshark logs at the moment the communication fails there is a BROKEN PIPE error on OUT endpoint. What is strange is that when the PC is connected directly to the MCU everything is working fine, but when MCU is connected to a USB hub the communication starts to fail with previously described behaviour. I have tried three different hubs that I know are working, nothing changes. When adding some other device to the HUB, like ST-Link the problem gets worse, the fails are more frequent. When connected directly, without the hub, no problem. When trying to send the same message again from the PC to the MCU, it works.