[lwip-users] Problem with pbufs on queue

[Zly]

Hello to everyone.

I'm writing driver for smc91c111 based ethernet card (on MIPS like 
system). I did some optimization on driver, and now it works faster but 
i'm getting assertion (before optimization it worked fine, but slower). 
The assertion I'm getting follows:

Assertion "tcp_enqueue: pbufs on queue => at least one queue non-empty" 
failed at line 158 in /lwip/core/tcp_out.c

The log for the previous version is:

tcp_enqueue(pcb=0x21cd5c, arg=0x0, len=0, flags=12, copy=0)
tcp_enqueue: queuelen: 0
quelen 1 (0 0)
tcp_enqueue: queueing 6510:6511 (0x12)
tcp_enqueue: 1 (after enqueued)
tcp_output_segment: 6510:6510
tcp_output: nothing to send (0x0)
+-+-+-+-+-+-+-+-+-+-+-+-+-+- tcp_input: flags -+-+-+-+-+-+-+-+-+-+-+-+-+-+
tcp_receive: ACK for 6511, unacked->seqno 6510:6511
tcp_receive: removing 6510:6511 from pcb->unacked
tcp_receive: queuelen 1 ... 0 (after freeing unacked)
tcp_output: nothing to send (0x0)
+-+-+-+-+-+-+-+-+-+-+-+-+-+- tcp_input: flags -+-+-+-+-+-+-+-+-+-+-+-+-+-+
tcp_output: sending ACK for 377797992
tcp_write(pcb=0x21cd5c, arg=0x411000, len=256, copy=0)
tcp_enqueue(pcb=0x21cd5c, arg=0x411000, len=256, flags=0, copy=0)
tcp_enqueue: queuelen: 0
quelen 1 (0 0)
tcp_enqueue: queueing 6511:6639 (0x0)
tcp_enqueue: queueing 6639:6767 (0x0)
tcp_enqueue: 4 (after enqueued)
tcp_output_segment: 6511:6639
+-+-+-+-+-+-+-+-+-+-+-+-+-+- tcp_input: flags -+-+-+-+-+-+-+-+-+-+-+-+-+-+
tcp_output: sending ACK for 377798062
+-+-+-+-+-+-+-+-+-+-+-+-+-+- tcp_input: flags 
-+-+-+-+-+-+-+-+-+-+-+-+-+-+ tcp_receive: ACK for 6639, unacked->seqno 
6511:6639
tcp_receive: removing 6511:6639 from pcb->unacked
tcp_receive: queuelen 4 ... tcp_write(pcb=0x21cd5c, arg=0x411100, 
len=128, copy=0)
tcp_enqueue(pcb=0x21cd5c, arg=0x411100, len=128, flags=0, copy=0)
tcp_enqueue: queuelen: 2 quelen1 1 (0 2216424)
quelen1 1 (0 2216424)


The log for the current version is:

tcp_enqueue(pcb=0x21bd5c, arg=0x0, len=0, flags=12, copy=0)
tcp_enqueue: queuelen: 0
quelen 1 (0 0)
tcp_enqueue: queueing 6510:6511 (0x12)
tcp_enqueue: 1 (after enqueued)
tcp_output_segment: 6510:6510
tcp_output: nothing to send (0x0)
+-+-+-+-+-+-+-+-+-+-+-+-+-+- tcp_input: flags -+-+-+-+-+-+-+-+-+-+-+-+-+-+
tcp_receive: ACK for 6511, unacked->seqno 0:0
tcp_output: nothing to send (0x0)
+-+-+-+-+-+-+-+-+-+-+-+-+-+- tcp_input: flags -+-+-+-+-+-+-+-+-+-+-+-+-+-+
tcp_output: sending ACK for 4113604214
tcp_write(pcb=0x21bd5c, arg=0x410000, len=256, copy=0)
tcp_enqueue(pcb=0x21bd5c, arg=0x410000, len=256, flags=0, copy=0)
tcp_enqueue: queuelen: 1
quelen1 0 (0 0)

Can you help me to determine what could be the problem with my driver, 
or is there some bug in lwIP library?

I would very much appreciate your help.

Kind regards,
              Maksovic Vladimir