[BUG] Sending MT3 and MT2 messages simultaneously causes message corruption.

[m-komo]

Describe the bug
Sending MT3 and MT2 to USB MIDI 1.0 device simultaneously corrupt MIDI messages.

To Reproduce

1. Set the Roland UM-ONE to class-compliant mode (set the switch to "TAB") and attach it to PC.
2. Make sure the device is running with the in-box USB MIDI 1.0 driver (USBAUDIO.sys).
3. Open midi.exe in two windows.
4. From one, send the attached TestUMP_MT2.txt to UM-ONE.
5. From the other, send the attached TestUMP_MT3.txt to UM-ONE.
6. Monitor USB OUT packets with a USB protocol analyzer.

Incorrect conversions of MT3/MT2 messages into USB MIDI 1.0 packets were observed.
As a result, some channel voice messages are lost and some SysEx messages are corrupt.

Expected behavior
No conversion issues.

Screenshots

Installer Name or Version

• Windows.MIDI.Services.In-Box.Service.-.1.0.1-preview.7.24305.1438-x64.exe

Desktop (please complete the following information):

• OS: Windows 11 24H2 build 26120.2702 (Insider Dev channel)

Device information, if this is with an external MIDI device:

• Roland UM-ONE mk2
• OS in-box USB MIDI 1.0 class driver (USBAUDIO.sys)

Application Information

• midi.exe

[Psychlist1972]

Please try this with DP8, released today, and let me know if you still see this behavior.

[Psychlist1972]

Actually, re-reading this, I don't think you will see any differences in DP8. We do not have sysex parking/blocking in place for this release. If one app sends notes while another sends sysex, they all end up in the output.

I will look more closely at what exactly happens with the data, but sysex collisions are an error condition right now, just as they are with most? all? vendor multiclient USB MIDI 1.0 drivers available today.

Related issue #60

[m-komo]

I verified messages sent to the driver from the/ MIDI stack, there were no mixed data bytes. Channel voice messages were simply inserted in the middle of a SysEx message.
Since the issue is not caused by the new MIDI stack, the situation is the same today.
I will try #60, when it becomes available.

@Psychlist1972, please kindly close this case.