Re: AW: 405GP Networking issue

[KISHINAMI Masaya <kishinami@cs.fujitsu.co.jp>]

Hi Georg,

Thank you for your suggestion. However, we once checked the EMAC0_MR1,
and it was right configuration. Sorry, not to be informed to you.
But I'll check once again. As a fact, this problem does not happen
everywhere. We need to go another place and it's far from here. Therefore,
next investigation will be held at the middle of next week.
I will keep you informed as more information becomes available.

Regards, Kishinami

--- On Fri, 28 Feb 2003 22:59:11 +0900 Georg Klug<gklug@giga-stream.de> -san wrote:

>> We are debugging a custom board designed based on the 405GP
>> (200MHz) and have a problem not being sent ECHO REPLY ping
>> packet from custom board to our PC via repeater hub on the
>> heavy traffic under 10Mbps and half duplex condition.
>
>> ...
>
>> Following are the our simplest duplication process and the
>> results.
>>
>> 1. Connect the repeater hub to backbone LAN.
>> 2. Connect custom board, test PC to ping and other PCs to the
>>    repeater hub to the full. This case, 10 or more PCs are
>>    connected to repeater hub and each PC works normally by
>>    using network.
>> 3. Increase the traffic by using ftp command. The ftp data was
>>    never addressed to the custom board.
>> 4. Ping from our PC to custom board at one time.
>> 5. The 60% pings were lost such condition.
>> 6. We investigated the ping lost case.
>>    - LAN protocol analyzer captured the ECHO REQUEST which was
>>      address to custom board. It shows ECHO REQUEST was issued
>>      from our PC to LAN cable.
>>    - Logic analyzer captured the same ping packet which was
>>      already been captured by LAN analyzer between PHY(Intel
>>      LXT971A) and EMAC. It shows ECHO REQUEST was reached just
>>      before the EMAC.
>>    - The LAN device driver's receive buffer did not receive the
>>      ECHO REQUEST by using printk command. We suspected that the
>>      ECHO REQUEST was not issued to the MAL(Memory Access Layer),
>>      therefore ECHO REQUEST was not translated to the receive
>>      buffer.
>>
>> At the same time, many 4 byte short packet(0x000000f0) which was
>> not addressed to custom board was received to the LAN device driver's
>> receive buffer with error status. According to 405GP manual, EMAC
>> discards the packet which is not of its own.
>
>to me it looks like an half duplex issue. You should check whether both:
>sender and receiver know that they are connected to a half duplex hub.
>Otherwise collisions could occur which are not detected by the receiver
>and also not by the transmitting entity. So you should make sure that
>FDE is set to 0 in the EMAC Mode register 1 (EMAC0_MR1) according to
>the Users manual)
>

-----
KISHINAMI Masaya
Fujitsu Limited (Japan)

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