ethernet: stm32_hal: wrong ptp clock is retrieved

[rary21]

I'm using gPTP stack with Nucleo STM32H753. I'm using zephyr v4.1.0
I noticed that the timestamp attached to the packet is sometimes incorrect.
For example, the timestamp associated with the Pdelay Req received by the STM seems to correspond to a slightly earlier packet.

Here's a log.
I added debug log to eth_rx in eth_stm32_hal and gptp_handle_pdelay_req in gptp_messages.c.
We can see that 3rd timestamp corresponds to first timestmap.

uart:~$ q[00:13:01.008,000] <inf> eth_stm32_hal: recvd ts in stm32 hal 1747807162260169250
uart:~$ q[00:13:01.008,000] <inf> eth_stm32_hal: recvd ts in stm32 hal 1747807162260472530
uart:~$ q[00:13:01.008,000] <inf> eth_stm32_hal: recvd ts in stm32 hal 1747807162260169250
uart:~$ q[00:13:01.008,000] <inf> net_gptp: pdelay req recvd ts: 1747807162260169250

[rary21]

It looks like that the default number of rx descriptors (=4) is not enough for my case.
I'll increase it to 8 and see if it fixes the problem.

[rary21]

This resolved the issue.