[ERROR in ewslot.c:508]

Question

I get during runtime of my allpication the message [ERROR in ewslot.c:508] .
I can't look inside ewslot.c because is part of the library. What does it mean?
Maybe this is the reason why my application crashes.

Kind regards
Giuseppe

Answer 1

Hi Giuseppe,

please let us know which target (Platform Package and Build Environment) you are using and which version of Embedded Wizard Studio you are using.

Do you get any other messages on the console via serial connection? Maybe you can provide the entire message from startup until the error happens.

Concerning the crash: Do you get some hard fault? Is this reproducible?

Best regards,

Manfred.

Comments

Hi Manfred,

We use STM32 RGB565 with a STM32F412, STM32CubeIDE version 1.8.0 and Embedded Wizzard version 8.30.
For the output of the error messages I do not use the serial interface. I route the message to a file on SD card.
The error occurs only at one customer, we have also replaced the hardware once, but no success. The customer says the display crashes several times in an hour. In the error file I also see several times the entry "[ERROR in ewslot.c:508]".

I have done long term tests, tried to set up the same environment as the customer, but no error in my tests.
I had hoped that an error message would be recorded, which would give an indication of the cause of the error. But I can't do anything with this message.  

Best Regards
Giuseppe

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Hi Giuseppe,

I think we are discussing two different topics:

1.) Error reported in ewslot.c - The error message is "'postsignal' is failed. The signal is just delivered."

This error indicates, that your application is trying to post again a signal which is actually in processing. In other words, a method that is currently executed in context of some signal X is trying to post again this signal X. Doing this could lead to endless signal delivery - the application would hang. Therefore the signal is ignored. The error message should just warn to review your application.

Please see also the end of the chapter postsignal.

2.) The "display crash"

Can you provide more information about the "crash"? What means "crash"? Is it reproducible somehow?

What is the difference between your environment and your customers environment?

Best regards,

Manfred.

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Hi Manfred.

Crash means a restart of the application (restart of the display).
This happens only at the customer. but unfortunately he is 200 km away from us.
In our area it's not reproducible. The display runs for several days without problems.
the message [ERROR in ewslot.c:508] did not come once, so I thought it might have something to do with it.
I think we need to analyze the environment at the customer more closely.

Best regards
Giuseppe

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Hi Giuseppe,

restart of the application can be triggered differently: Restarting the application because of some hardfault or because of some timeout / watchdog. This means, either the application is really running in some erroneous state or it was (for some reasons) not fast enough...

Best regards,

Manfred.

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Hi Manfred.

The problem is solved. The cause was in the LIN communication.
I have updated an EW property within the LIN Rx interrupt routine, which in turn triggered a notifyobservers. This then led to the crash.
Since I took the property update out of the interrupt routine the application no longer crashes.
Thanks for your support.

Best Regards
Giuseppe.

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Hi Giuseppe,

thanks for sharing the results and great to hear that you found the reason.

Just for others having same unpredictable crashes: It is necessary to ensure that Embedded Wizard functions are invoked in context of the GUI thread only. If a foreign thread does intent to report a state alternation to the Embedded Wizard GUI application, it has to relay this event (e.g. via operating system queues). The same applies to interrupt routines (e.g. in case of a bare-metal application). Please see the section Multi-threading and interrupt service routines in the chapter Device Property.

Best regards,

Manfred.