Re: [lwip-users] Packet queuing to an ARP table entry

[Simon Goldschmidt]

Amena El Homsi wrote:
> Actually I had this understanding from this link 
> http://www.nongnu.org/lwip/2_0_x/group__pbuf.html

That page says "PBUF_ROM: pbuf data is stored in ROM". Could you tell us from 
which line on that page you have your understanding from?

>  and from the Dunkels book " Design and Implementation of the lwIP TCP/IP 
>Stack".

That one is totally outdated. The stack at that time didn't handle zero copy RX 
or TX correctly.

> Thanks for your clarifying, but is there a serious problem in using PBUF_ROM 
> as I did? 

I tried to explain that before. Your ROM is not ROM. Data must be kept 
unchanged until it is actually sent. How do you ensure this??

>> Regarding your original problem: why don't you put (some of) the memp pools 
>> into the
>> frame memory?
> I don't think this will be easy because we have our own memory manager system 
> and the frame memory will be used by the HW MAC and SW MAC, however pools are 
> managed by PBUF manager.
> It seems that I am facing a serious problem now, your suggestions are really 
> appreciated..

As I don't know your exact hardware/software setup, how could I suggest 
anything more here?


Simon