Dear Linux Audio Dev Team,

I am looking to re implement and publish with the help of Wireshark a software like Line6 PODHD 500x Edit for my POD HD500X (modification of guitar pedal effects). To do this I need to claim the usb interface that is already used by the snd-usb-podhd and redo the initialisation, also already done by snd-usb-podhd. Therefore, to have both the audio and the pedal management I would need to modify the module mentioned above. This would aim to create a bridge between kernel and the userspace, that redirects the usb urb bulk requests that are not used by the audio part, to an interface (only isochronous is used after the init).

In the objective to be merged upstream in the future, how should I proceed:

• Use midi interfaces and create a fake one, knowing that the proprietary but readable protocol is not midi compliant?
• Create a char device for the podhd pedal boards? Within the same module?
  
• Other suggestions?

In the same way, I am looking for suggestion regarding the data transmitted within this interface. Would something like struct {int message_len, char * data} be sufficient to be transmitted at every urb bulk request?

Thanks in advance,

Nicolas SCHWARTZ

PS: I can share with you my test code and my current analysis on the messages sent/received by the pod when clicking on buttons/sending message from the PC, if needed.