USB CDC stm32u575/85 double payload with 64 bytes and extra data with payloads over 320 bytes

[adam-embedded]

I am trying to use USB CDC. I have tried the CDC dual port example with both freeRTOS and bare metal. No matter what I try I get 128 bytes when sending exactly 64 bytes from the pc to the device. if I send 65 it works fine, I get 64 bytes plus 1 byte in two read operations. If I use another USB stack such as USBX, this does not suffer from the issue.

If I send more than 320 bytes I get random data mixed in with the real data that is transmitted. The thing that is interesting that any payload I receive the extra data is divisible by 64.
I have tested with MacOS and windows and get the same behaviour.

I hope someone can help me with this issue.

[HiFiPhile]

That's sounds terrible, maybe there is a new synchronization issue like #2515 (@Lurcy38 works for ST)
I took a look of U5 HAL code, there are few changes but I didn't spot anything really suspicious. And I don't have the board to test.

You can enable the logging to see if the transfer complete event firing doubled.