[ECOS] Problem with MGETHDR

[ECOS] Problem with MGETHDR

[Rupesh Kumar]

Hi all,

I am running the http server on eCos (MLB HTTP Server).

In my ethernet driver eth_drv_recv function in in ISR Context.
After Receving some packets eth_drv_recv function is failing.so i am not
able to receive any more packets.

I have found that eth_drv_recv() is failing at MGETHDR Macro call.At the
time of failing it is not even entering the macro call.(this i found by
putting some traces in the MGETHDR Macro Call).

Kindly share your views on this

Regards
rupesh




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Re: [ECOS] Problem with MGETHDR

[Gary Thomas]

On Mon, 2005-06-13 at 19:14 +0530, Rupesh Kumar wrote:
> Hi all,
> 
> I am running the http server on eCos (MLB HTTP Server).
                                        ^^^^^^^^^^^^^^^
There is no such thing;  there is a sample HTTP server setup on the MLB
website which uses standard eCos with a publicly available HTTP server.
I'm sure this is what you meant :-)

> 
> In my ethernet driver eth_drv_recv function in in ISR Context.
> After Receving some packets eth_drv_recv function is failing.so i am not
> able to receive any more packets.
> 
> I have found that eth_drv_recv() is failing at MGETHDR Macro call.At the
> time of failing it is not even entering the macro call.(this i found by
> putting some traces in the MGETHDR Macro Call).

What platform/target?

Most likely, something is going wrong in your application code,
possibly a stack overflow, etc.  

-- 
------------------------------------------------------------
Gary Thomas                 |  Consulting for the
MLB Associates              |    Embedded world
------------------------------------------------------------


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Re: [ECOS] Problem with MGETHDR

[Gary Thomas]

On Mon, 2005-06-13 at 07:55 -0600, Gary Thomas wrote:
> On Mon, 2005-06-13 at 19:14 +0530, Rupesh Kumar wrote:
> > Hi all,
> > 
> > I am running the http server on eCos (MLB HTTP Server).
>                                         ^^^^^^^^^^^^^^^
> There is no such thing;  there is a sample HTTP server setup on the MLB
> website which uses standard eCos with a publicly available HTTP server.
> I'm sure this is what you meant :-)
> 
> > 
> > In my ethernet driver eth_drv_recv function in in ISR Context.
> > After Receving some packets eth_drv_recv function is failing.so i am not
> > able to receive any more packets.
> > 
> > I have found that eth_drv_recv() is failing at MGETHDR Macro call.At the
> > time of failing it is not even entering the macro call.(this i found by
> > putting some traces in the MGETHDR Macro Call).
> 
> What platform/target?
> 
> Most likely, something is going wrong in your application code,
> possibly a stack overflow, etc.  

Also, have you tested your ethernet driver with other applications,
e.g. the standard eCos tests?  Do this to verify the robustness of the
driver independent of application code.

-- 
------------------------------------------------------------
Gary Thomas                 |  Consulting for the
MLB Associates              |    Embedded world
------------------------------------------------------------


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Re: [ECOS] Problem with MGETHDR

[Gary Thomas]

Please reply to the mailing list so that all may benefit; private 
support is only available under contract.

On Mon, 2005-06-13 at 19:41 +0530, Rupesh Kumar wrote:
> Hi Gary,
> 
> I am running the http server Published on MLB site.Target Board is ARM
> (ARM926EJS) Board.
> 
> what i am assuming is MGETHDR will get the kernel buffers,does it has
> any thing to do with application buffers.(Correct me if i am wrong).

This is true - the network stack has its own set of buffers which are 
manipulated via MGETHDR, etc.  However, since eCos has a flat, 
unprotected memory model, your application can easily mess things up
so that that pool is no longer managed properly.

As I said in a previous email, verify that your network driver is
working properly first, then investigate what's going wrong.  

One thing that's always a good idea is to enable assertions in the
eCos kernel.  This can help find problems quickly, even elusive ones
like stack overflows.  To enable this, enable CYGPKG_INFRA_DEBUG

> 
> Regards
> rupesh
> 
> On Mon, 2005-06-13 at 19:25, Gary Thomas wrote:
> > On Mon, 2005-06-13 at 19:14 +0530, Rupesh Kumar wrote:
> > > Hi all,
> > > 
> > > I am running the http server on eCos (MLB HTTP Server).
> >                                         ^^^^^^^^^^^^^^^
> > There is no such thing;  there is a sample HTTP server setup on the MLB
> > website which uses standard eCos with a publicly available HTTP server.
> > I'm sure this is what you meant :-)
> > 
> > > 
> > > In my ethernet driver eth_drv_recv function in in ISR Context.
> > > After Receving some packets eth_drv_recv function is failing.so i am not
> > > able to receive any more packets.
> > > 
> > > I have found that eth_drv_recv() is failing at MGETHDR Macro call.At the
> > > time of failing it is not even entering the macro call.(this i found by
> > > putting some traces in the MGETHDR Macro Call).
> > 
> > What platform/target?
> > 
> > Most likely, something is going wrong in your application code,
> > possibly a stack overflow, etc.  
> > 
> > -- 
> > ------------------------------------------------------------
> > Gary Thomas                 |  Consulting for the
> > MLB Associates              |    Embedded world
> > ------------------------------------------------------------
> > 
-- 
------------------------------------------------------------
Gary Thomas                 |  Consulting for the
MLB Associates              |    Embedded world
------------------------------------------------------------


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