Audio and CDC

[pschatzmann]

I started to work on some Audio classes: the Speaker and Microphone seem to work fine if I have CDC deactivated.
As soon as I activate the CDC in the descriptor, things stop from working.

• CDC only is working (with this default descriptor)
• Audio only is working (with this descriptor)
• Combined is crashing (with this descriptor)

I am currently clueless what could cause this and I would need some advice how to tackle this!
How can I identify the root cause ?

My current implementation can be found here

[znmeb]

I've got a pretty good Linux test bench set up if anyone wants me to run tests. My guess from the symptoms is that the event loop isn't getting to something in time, but I don't know Arduino internals well enough to know how to chase that down.

[pschatzmann]

I just found out that the Microphone is working: the issue is only with the Speaker: I guess you might be right.

dmesg is giving

[29056.091407] usb 1-1.3: new full-speed USB device number 4 using xhci_hcd
[29056.169071] usb 1-1.3: config 1 interface 3 altsetting 1 has a duplicate endpoint with address 0x82, skipping
[29056.169973] usb 1-1.3: New USB device found, idVendor=239a, idProduct=cafe, bcdDevice= 1.00
[29056.169982] usb 1-1.3: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[29056.169985] usb 1-1.3: Product: Pico
[29056.169988] usb 1-1.3: Manufacturer: Raspberry Pi
[29056.169991] usb 1-1.3: SerialNumber: E66130100F728A38
[29056.184331] cdc_acm 1-1.3:1.0: ttyACM0: USB ACM device
[29063.509549] intel_powerclamp: Stop forced idle injection
[29099.639793] usb 1-1.3: 3:1: cannot get freq (v2/v3): err -110
[29104.758607] usb 1-1.3: 3:1: cannot set freq 44100 (v2/v3): err -110
[29110.901461] usb 1-1.3: 3:1: cannot get freq (v2/v3): err -110
[29116.023052] usb 1-1.3: 3:1: cannot set freq 44100 (v2/v3): err -110
[29122.166381] usb 1-1.3: 3:1: cannot get freq (v2/v3): err -110
[29127.285836] usb 1-1.3: 3:1: cannot set freq 44100 (v2/v3): err -110
[29133.429660] usb 1-1.3: 3:1: cannot get freq (v2/v3): err -110
[29138.549584] usb 1-1.3: 3:1: cannot set freq 44100 (v2/v3): err -110
[29144.693207] usb 1-1.3: 3:1: cannot get freq (v2/v3): err -110
[29149.813785] usb 1-1.3: 3:1: cannot set freq 44100 (v2/v3): err -110
[29155.955729] usb 1-1.3: 3:1: cannot get freq (v2/v3): err -110
[29161.076374] usb 1-1.3: 3:1: cannot set freq 44100 (v2/v3): err -110
[29167.219327] usb 1-1.3: 3:1: cannot get freq (v2/v3): err -110

[pschatzmann]

Oh, the culprit was this

[29056.169071] usb 1-1.3: config 1 interface 3 altsetting 1 has a duplicate endpoint with address 0x82, skipping

When things were not working, I alligned the logic closer to the original TinyUSB speaker example and based the fb endpoint on the speaker endpint | 0x80: It seems that this was a mistake.

It's working now...