Midi from USB not coming in since 1.13.2


On my Dwarf, since the last update (1.13.2) I have trouble with midi coming from my midi controllers (Morningstar MC6 Pro and Beat Bars E&F2M).

  • I have no problem receiving midi through USB from Dwarf → Morningstar (I use the Infamous Mindi to change bank, and it works every time)
  • when midi is coming via USB from Morningstar → Dwarf is not working !
  • if the midi can work with the Morningstar it doesn’t necessary work with the expression pedal plugged in the Beat Bars E&F2M and vice versa.

After rebooting the Dwarf it can work perfectly again.

How to reproduce

  1. boot the Dwarf
  2. load any pedalboard with mapped midi
  3. try to send midi to the Dwarf :
  • I generally can’t received midi to the Dwarf through USB, even if the Dwarf is only sending the midi message directly to the midi out.
  • BUT if I use the 3.5 jack-midi input it all works perfectly.
  • Bonus : check if the Dwarf can send some midi messages to the controller (it always works for me)

Additional information

  • virtual midi loopback enabled
  • midi port in separated mode

setup :

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huh… so far i’m only sending midi to my dwarf ( from an m-vave chocolate - it has not yet failed. does it still fail for you if you eliminate the hub?


ok… weird… i’ll test input from some other MIDI devices and report back.

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hi @Rom ! i just did a test …

m-vave Chocolate, novation ReMOTE 25SL, and Behringer BCR200, all through a Kopplen HUB-USB02SGR (4-port) hub into the Dwarf. i also had an expression pedal coming into the MIDI DIN input of the 25SL from a DIY MIDI controller - can’t use the expression pedal input on the 25SL because it’s currently on the fritz. i assigned various controls (including switches, knobs, faders, expression pedal, and keyboard) from each controller to do various distinct things in my pedalboard. i rebooted the Dwarf 10 times; everything worked flawlessly every time.

virtual midi loopback enabled, and ports in separated mode as you did.

one possibly interesting note: the Chocolate and BCR2000 were recognized and functional immediately after the Dwarf was rebooted, but i always had to unplug and reconnect the 25SL after Dwarf reboot before it was properly recognized and functional.

sorry i didn’t test output from the Dwarf to anything else.

:person_shrugging: :thinking:

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Oh thanks for the tests !!!
I can’t reproduce the problem, it seams that it’s happening if I boot (or reboot) when the Dwarf is quite hot (75°C in the webUI)…
I didn’t try to downgrade too, I’ll take time to do it next week.

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It really seams like a temperature problem, if I boot from “cold” midi always comes to life !

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okay… I’ve reproduced the problem, in fact 2 problems :

  • my main pedalboard uses 83% of the CPU, it seams that when the Dwarf heats a bit, it doesn’t respond to midi messages. When it happens, if I switch to a 256 buffer, restart the, everything goes to normal.
  • when too many mini messages are send at the same time, the Dwarf take only 2 or 3 messages. I’ve put a delay time between each messages in the Morningstar configuration, and everything is okay when I set a 4ms delay.

huh… interesting finding @Rom .

it’s a weird one, with a strange workaround. glad you now understand it, and have a method to deal with it!

it’ll be interesting to hear from MOD folks whether or not this might be somehow fixable in software, given that it is also temperature related!

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