not seeing USB device with DISCOVERY demo

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chibby
Posts: 66
Joined: Wed Oct 22, 2014 11:20 am

Re: not seeing USB device with DISCOVERY demo

Post by chibby »

Well I have just tested this on separate hardware ( laptop ) running an earlier Fedora 20 , plus booted the desktop machine from Arch linux and Parition Magic 4.8 live ISO images.

None of them show the ADC device.

Returning to my original set up I am not even getting the -110 errors, the device is just not happening.

Reflashing the Vedder USB-CDC it is straight back in with /dev/ttyADC0

This does not seem particularly linked to either the distro, kernel or the hardware. That seems a broad enough target if you can find a Discovery board to test.

Anyway it does not look like ChibiOS is robust enough for my machine control application which I certainly won't be controlling from a Windows host.

Best regards.
chibby
Posts: 66
Joined: Wed Oct 22, 2014 11:20 am

Re: not seeing USB device with DISCOVERY demo

Post by chibby »

Just in case anyone else hits this problem I have found that running in the debugger worked. This led to finding a service called ModelManager that was trying to communicate with the new /dev/ttyACM0 device to identify whether it is a model device.

Something to do wiht DTR line not being implemented seems to lead to a lock of the Chibios end.

Stopping the ModelManager service is a work around for this problem.
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Re: not seeing USB device with DISCOVERY demo

Post by Giovanni »

It is not a lock, the endpoint is stopped to signal that the service is not available. The OS and the application continue to run.

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Re: not seeing USB device with DISCOVERY demo

Post by chibby »

Yes, thank you for that clarification. It is not crashing Chibios, just blocking the demo from functioning.

It seems this is an issue that has been known for years with this dumb ModemManager service. Most distros have adopted a blacklist system within the udev structure:
https://bugzilla.redhat.com/show_bug.cgi?id=1261040

This is how a similar problem was fixed when it screwed up Arduinos and various radio devices.

This is certainly something that ChisbiOS should communicate to potential users, it has taken me days to get to the bottom of this. At least this thread will provide a potential hit for search engines but I think there should be a mention in doc or the presentation. Potential ChibiOS adopters may not be a tenacious as I have been when finding the demos don't work.
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