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Midi device sends endless output in response to Sysex (Mac OS)

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Dominik
Posts: 3
Active Member
Topic starter
 

Older versions of Midi communication plugins, as well as the Windows version, upon sending the Sysex receive 1 Sysex response from the Midi device.

However, using a new, non-deprecated set of plugins, when I send the Sysex I receive thousands of responses, which continue endlessly until a new Sysex is sent, whereupon it switches the output to respond to the Sysex but continues in an endless loop, sending thousands of outputs.

Has anyone had a similar issue? I don't understand why the device would send one Sysex response normally, but now, it clearly understands the Sysex (as the output corresponds), yet it insists on sending thousands of messages (including some that weren't specifically requested). If nobody can relate to the problem, is there a MIDI command that will tell the device to stop sending System exclusive messages?

The photo below shows an example of the frenetic activity of the device.

 
Posted : 12/05/2021 7:08 am
Geoff
Posts: 1039
Noble Member
 

This sounds wierd, and totally useless. As you describe it.

It sounds like a DUMP REQUEST. Such a SysEx instruction would normally include a memory range, i.e. a start address and an end address, and the device would send all the data between the two addresses, and if there is a LOT of data then this could be a large number of packets.

Have you checked that your initial REQUEST SysEx command has not got a memory address messed up so that a small range has become a massive range?

The data you show on the screen does not seem to be repeated - I'll need to try to download something and study your snapshot more closely, if that is possible.

I assume you could just turn the 'device' off?

Once a BULK DUMP has been set in motion, it may not be possible to enact a further SysEx command??

Update - looking again at the data showing in the .PNG, there is a lot of evidence of repetition although the data is nothing like complete. There may well be a pattern of a number of lines being repeated, but the repetition may well be a LOT of data??

Geoff

 
Posted : 12/05/2021 9:12 am
Dominik
Posts: 3
Active Member
Topic starter
 

The device immediately responds to further Sysex commands, it just responds to changing the output to endless loops of the action of the new Sysex.

I think it is a problem with the plugin I am using (MBS for Xojo), as using the CoreMIDI API on Swift/Xcode to send the same instructions has normal behaviour. As such, I don't think this forum can help much.

 
Posted : 12/05/2021 10:21 am
Geoff
Posts: 1039
Noble Member
 

Yes, it sounds like the plugin is causing the problem, but it's a rather serious problem to have missed being spotted by normal testing before release.

Geoff

 
Posted : 12/05/2021 10:31 am
Mike Kent
Posts: 85
Trusted Member
 

It sounds like an infinite loop. Turn off the MIDI Thru in the Application.

Chair of MIDI 2.0 Working Group

 
Posted : 12/05/2021 7:20 pm
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