Re: [lwip-users] tcp_enqueue fails at more than two tcp_enqueue's

[Kieran Mansley]

On Fri, 2010-04-30 at 21:36 +0100, Jimi Simpson wrote:

> I expect there may be too little information here for anyone to get a
> true grasp of what might be happening, but if any one of you can
> ask/state some obvious things to check/share then I am sure it's going
> to be something silly. 

The problem you describe is definitely incorrect behaviour - it should
work fine doing what you're doing.

Can you give more detail about the symptoms when it goes wrong?  If you
can see the output of printfs in your project you could try enabling the
lwIP debug statements which might give some hints.

When you try to send more data than can be sent immediately, some of it
will be queued and sent later.  It sounds like this action of queueing,
or perhaps of trying to send the queued data later, is causing your
problems.

The most common source of problems with lwIP is where people have used
the stack from too many threads, or not properly set up the interface to
the device driver so that interrupts collide with application threads in
the stack and corrupt the state.  Could you give details of:
 - which lwIP port and version you are using?
 - is your web server app based on one that we will be familiar with
(e.g. from lwIP contrib module)?
 - your lwipopts.h setting
 - a description of your threading module, and details of how packets
are passed to lwIP by the device driver.

Thanks

Kieran