On Mon, Nov 20, 2023 at 10:33:38AM +0100, linux@xxxxxxxxx wrote: > I run the test and it worked fine. The transmitted data matches with > the recived data, no diff. ok, thanks for confirming. At least we are on the same page. > BUT!!! on the MDIO it is completly different !!! > When I request to send 4kB Data I measure on the line 16384Byte. > > The data is again 3Dummy Bytes followed by the databyte. > So the error symetic on send and recive ok, that's annoying. I wonder if the loopback test could be improved to spot such kind of issues, maybe we could verify if the execution time is reasonable given the SPI clock frequency and the payload size ... Francesco