[ECOS] ecos + lwip

Simon Kallweit simon.kallweit@intefo.ch
Thu Sep 3 09:04:00 GMT 2009

Mandeep Sandhu wrote:
> On Thu, Sep 3, 2009 at 2:34 PM, Simon Kallweit<simon.kallweit@intefo.ch> wrote:
>> Mandeep Sandhu wrote:
>>> On Thu, Sep 3, 2009 at 2:22 PM, Simon Kallweit<simon.kallweit@intefo.ch>
>>> wrote:
>>>> Mandeep Sandhu wrote:
>>>> There is a semaphore created in cyg_lwip_sequential_init() which will
>>>> block
>>>> until all initialization (including ethernet devices) in the tcpip thread
>>>> is
>>>> done. Therefore it's priority does not matter. cyg_lwip_sequential_init()
>>>> should not return before initialization is completed.
>>>> I just reviewed the code and found that the semaphore is initialized with
>>>> 1,
>>>> which is clearly a bug, it should be initialized with 0 so that the
>>>> following call to cyg_semaphore_wait() is actually blocking the thread
>>>> until
>>>> initialization is done.
>>>> My mistake, sorry! Hope it works as intended now. New release:
>>>> http://download.westlicht.ch/lwip-20090903.tar.gz
>>> Thanks Simon. I totally missed the sem init part...i guess since the sem
>>> is
>>> init to 1...the thread never actually waits...and thats why I was seeing
>>> the
>>> problem.
>> Exactly. I glanced over this code more than once and it didn't occur to me.
>> Thanks a lot for testing! This is really helpful.
> No problem. I'm just glad I'm able to help.
> I downloaded your new rel. It still had that sem init'ed to 1! That should be
> 0 right? If thats the only change I'll do it in my local copy and test it.

Oh my, git tricked me :) Yeah, this should be 0. Please see if that 
works. It did for me, before git tricked me, hehe


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