Hello everybody, If you already have discussed it in some threads please forgive me and help me with a link to that thread.
I was porting lwIP (I am using latest code from CVS, not any stable build) for Nucleus running on a ARM9 core uP. I am stuck with the following problem; this looks like a deadlock: I have a TCP client (a single socket in a single thread) doing HTTP download from a remote server. I have CS8900A ethernet driver (btw I have heard in some sites that there is a CS8900A driver implementation available for lwIP, but could not find any). posting packets throught netif->input (tcpip_input) into 'mbox' mailbox. After receiving a few segments everything stops working. I did some investigation and saw that tcpip_thread is waiting on conn->recvmbox to post received packets as mailbox posts on full mailboxes are blocking. Driver is waiting on mbox to post packets it has received. Application is waiting on mbox to post do_recv API message. I have investigated further and found out that in netconn_recv we should actually keep emptying conn->recvmbox in order for the tcpip_thread to keep going. In the case of Nucleus the mailbox size is only four and if it so happen that to consume a single TCP segment application thread takes as much time as 9 segments are produced by the driver then by the time application thread comes to post do_recv into mbox it is already filled up by driver. I have observed that adjusting the priority of three threads properly; it can be handled but for multiple thread each fetching using a number of sockets will lead to the same problem. Please help me with some light. Am I missing something obvious? Thanks in advance, Bikram -- Bikram Chatterjee Senior Engineer Alumnus Software Limited Kolkata
_______________________________________________ lwip-users mailing list lwip-users@nongnu.org http://lists.nongnu.org/mailman/listinfo/lwip-users
