On 03.05.2021 15:31:34, Ayoub Kaanich wrote:
> For the ack bit, I think we could go with the bit being a “NO_ACK”
> bit, so a spy listener will set it to 1, if it receives a CAN frame,
> but it does not see any node in the bus acknowledging it. This way we
> preserve backward compatibility.

As Vincent pointed out, the device should not receive the CAN frame that
has not been acked as I do on the flexcan.

And even on the mcp251xfd, where I receive the CAN frame, there's no way
to tell if this frame has been acked or not.

> For the FDF flag, check the MTU is not an option here, since this flag
> is needed to detect normal CAN frames being transmitted on a CAN-FD
> bus (The bus could be configured as CAN-FD, but the received frame
> could be a normal CAN frame)
> 
> If we are adding flags to can_frame, could we make sure it’s on the
> same byte offset as the flags of can_fd_frame, since PCAP format have
> no concept of MTU or struct size.

Sure - Do struct can_fd_frames have a different ARP header type?

Marc

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