Re: SV: [lwip-users] Odd byte packets in LWIP

[Leon Woestenberg]

Hello all,

could you please provide us with example source code?

There have been a number of bug reports/patches and
remarks about my cs8900.c code not allowing odd
alignment and/or 8-bit interfacing to the chip.

Also, there has been talk to split the cs8900 Ethernet
driver in an chip independent part (for most, the *if
functions) and a chip dependent part. That way, we
would have a Ethernet driver top layer (that does all
the ARP interfacing etc.)

If we want to fix this, we should both add 8-bit
alignment and 8-bit interfacing in a neat way. No
hacks.

Sorry for me neglecting the reports you sent me
earlier. It never reached the top of my priority list
and probably never will...

I will accept clean patches against DEVEL, but I
do not have the time to merge changes to old
versions of the driver.

Regards,

Leon.

----- Original Message ----- 
From: "Andreas Zippel" <address@hidden>
To: "Mailing list for lwIP users" <address@hidden>
Sent: Tuesday, November 11, 2003 4:45 PM
Subject: Re: SV: [lwip-users] Odd byte packets in LWIP


Hi
i rewrote the code of the cs8900 driver to accept odd payload length and
do a byte transfer in this case. this solution help me very good but
with the tradeoff that the throughput goes down a little bit. but it works.

regards andreas

Jan Wester wrote:
> Hi
> We have also tested CS8900, we solved the problem by adding a 2k buffer
> to read out all payloads to and sened that to the controller.
> You can't add space to you payloads, it corrupt your data
> //Jan
>
>     -----Ursprungligt meddelande-----
>     *Från:* address@hidden
>     [mailto:address@hidden *Nishen
Naidu
>     *Skickat:* den 11 november 2003 13:00
>     *Till:* Mailing list for lwIP users
>     *Ämne:* Re: [lwip-users] Odd byte packets in LWIP
>
>     Hi,
>
>     I'm using a c8900 ethernet chip and I do know it
>     has a problem wit odd length packets.
>     Any idea what a solution to this problem might be?
>     Do you automatically make all the packets you send out even length?
>     I could not do this since the client on the other side requires the
>     packet
>     length to be correct i.e. odd in this case.
>     The packets get sent out correctly if I make the packet even just
>     before I call
>     the netconn_write, but I don't want to do it this way due to the
>     above reason.
>     If I make the 'frame length' in the ethernet driver fot lwip even
>     then the packets
>     still do not get send correctly.
>     Any ideas?
>
>     Thanks
>     Nishen
>
>
>     ----- Original Message -----
>     *From:* Jan Wester <mailto:address@hidden>
>     *To:* Mailing list for lwIP users <mailto:address@hidden>
>     *Sent:* Tuesday, November 11, 2003 11:31 AM
>     *Subject:* SV: [lwip-users] Odd byte packets in LWIP
>
>     Hi
>     I had problem with odd length in the driver for Ethernet Controller,
>     depending on the hardware how the Ethernet Controller is connected
>     to the processor.
>     We use ARM with Davicom Ethernet Controller.
>     We also got problem with odd startaddress for buffer, but I think
>     what is ARM specific.
>     file://Jan
>
>         -----Ursprungligt meddelande-----
>         *Från:* address@hidden
>         [mailto:address@hidden
>         *Nishen Naidu
>         *Skickat:* den 11 november 2003 07:29
>         *Till:* Mailing list for lwIP users
>         *Ämne:* [lwip-users] Odd byte packets in LWIP
>
>         Hi
>
>         I'm having a problem sending out packets of odd length on
>         certain occasions.
>         Does lwip work well with odd length packets?
>         I read the following comment in some lwip sample code:
>         /*
>
>         Important!!! LwIP data alignment issue:
>            As of now LwIP code does not handle odd byte length packets
>         properly. So round packets to even byte
>            length by adding space characters (' '). This is true only
>         for processors that cannot handle
>            mis-aligned memory access.
>
>         */
>         is this correct??
>
>         Thanks
>         Nishen
>
>     ----------------------------------------------------------------------
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>
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