[ELDK] R: R: Resource temporarily unavailable

[Stefano Babic]

On 11/12/2010 05:55 PM, Luigi Rizzi wrote:
> Hi Stefano,
> a problem on the handshake line CTS is what I thought at first. I recompiled
> the kernel setting NONE on every signal (RTS,CTS,CD,DTR) but nothing has
> changed: everything works properly only on the STK board.

Indeed, it seems the SCC is waiting for line controls...

> I check lots of times.. but it looks like there are no differences between
> my carrier board and STK board, regarding these serial line signals. 

Have you check the pins on the processor ?

> 
> By the way, I noticed that with parameter "Number of TX DB for SCC2" set to
> 4, I get no error response for the first four write call: 
> 
> # ./test /dev/ttyS1
> sending...
> sending...
> sending...
> sending...
> 
> sending...
> serial_tx: Resource temporarily unavailable
> sending...
> serial_tx: Resource temporarily unavailable

This makes sense. You select 4 buffer descriptor, but the SCC is not
able to send data on the line. When all BD are filled, there is no space
available anymore and you get the error. It seems that no interrupt is
generated (you can easy check if it is the case).

> There's in your opinion something else I can check?

You can check the BDs and see if the SCC reports some error, and check
the PORT-C register to be sure that RTS/CTS and CD2 are not connected to
the extern.

Regards,
Stefano Babic

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