RE: [lwip-users] tcp_write() errors on snd_queuelen

[Tim Lambrix]

Simon,

I am using the latest TI library code that they have.  I asked if they were 
working on a port of version 1.4.0 but they said no.  Maybe they are waiting 
for it to be released first.

I do have a couple questions relating to the lwIP processing.  First, tcp_write 
is almost always going to be called from the application code outside of the 
interrupts.  So when a Ethernet hardware receive ISR goes off, how is it 
normally prevented from interrupting the tcp_write function? Or, should the 
interrupt service routine be allowed to go off but know that a tcp_write 
function call is in progress?

What should I be asking TI at this point to solve this problem?

Thanks,
Tim



-----Original Message-----
From: address@hidden [mailto:address@hidden On Behalf Of Simon Goldschmidt
Sent: Wednesday, March 16, 2011 9:43 AM
To: Mailing list for lwIP users
Subject: RE: [lwip-users] tcp_write() errors on snd_queuelen


Tim Lambrix <address@hidden> wrote:
> However, at line 3765, the tcp
> receive interrupt went off during a tcp_write (tcp_enqueue).

That statement makes me nervous as lwIP's concurrency model does not allow the 
core stack to be called from different threads, which includes almost 
everything except the mem(p)_*(), pbuf_*() and sys_*() functions (apart from 
the netconn- and socket API functions).

If your driver (ISR- or receive-thread) directly calls into the stack, that's a 
very good explanation of the error you see (and I think I remember Kieran had 
also already suspected something like this).

> I am using a TI Cortex-M3
> Stellaris port of the lwip code. If you think it is a porting issue, I can try
> to explain this TI?

Is this an old version of the port? I think I remember them having a problem of 
that sort somewhere in an older port, but I'm not sure...

Simon
-- 
GMX DSL Doppel-Flat ab 19,99 Euro/mtl.! Jetzt mit 
gratis Handy-Flat! http://portal.gmx.net/de/go/dsl

_______________________________________________
lwip-users mailing list
address@hidden
http://lists.nongnu.org/mailman/listinfo/lwip-users