iOS 15: new USB MIDI Port ID at each re-connection


we are facing a weird issue with iOS 15: for some USB/MIDI devices, each time they get connected to the iPad via USB (or rebooted), we get a different Port ID.
Since our host relies on the Port ID to reconnect the Port to the graph, the result is that the Port appears disconnected, and of course, the user is frustrated :slight_smile:
We cannot yet understand what those devices have in common. A couple of devices that show the problem are: Yamaha Motif, Yamaha Piaggero.
Here is an excerpt of the XML where we save the Port IDs each time a MIDI device connects.

      <MIDIOUTPUT name="YAMAHA MOTIF XF7 Porta 1" id="-119648265 1118310184" custom_name=""/>
      <MIDIOUTPUT name="YAMAHA MOTIF XF7 Porta 1" id="201398083 -1156807127" custom_name=""/>
      <MIDIOUTPUT name="YAMAHA MOTIF XF7 Porta 1" id="1881473804 1258374163" custom_name=""/>

Someone experiencing the same issue?


1 Like

Hi Emanuele,

This would explain what is happening to my 2021 M1 iPad Pro when I use it to play live. I use a MIDI Keyboard controller connected via USB. I use the GarageBand and KORG app and they both do the same thing.

Since updating to iOS 15 on the the connection to the keyboard will not resume if it is interrupted. When it gets disconnected it takes me up to 10+ attempts before it reconnects. I try rebooting the apps and the iPad.

So now I have to leave the iPad and Keyboard on all the time throughout the set which isn’t the end of the world, it just drains the battery quite quickly.

Looks like maybe that ID change might be the cause. The issue is easily reproducable.

Seems it’s an Apple bug?

Upgraded to 15.2.1 and the bug is fixed. My keyboard reconnects properly every time.

In our case no iOS 15 update has solved the issue.
With 15.4.1 it is even worst: connecting the MOTIF to the iPad via USB makes it unusable with any music application. Many apps do not boot, they get stuck. If I disconnected the MOTIF everything works. The connection was direct without using hub or not apple adapters.