device descriptor error

[dgsiegel]

When you start uvc-gadget, you can find these errors in dmesg:

[ +26,669352] usb 1-6: new high-speed USB device number 76 using xhci_hcd
[  +0,317065] usb 1-6: device descriptor read/64, error -71
[  +6,408941] usb 1-6: device descriptor read/64, error -71
[  +0,222872] usb 1-6: new high-speed USB device number 77 using xhci_hcd
[  +0,137456] usb 1-6: New USB device found, idVendor=1d6b, idProduct=0104, bcdDevice= 1.00
[  +0,000012] usb 1-6: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[  +0,000007] usb 1-6: Product: Piwebcam 
[  +0,000007] usb 1-6: Manufacturer: Show-me Webcam Project
[  +0,000006] usb 1-6: SerialNumber: 100000000d2386db
[  +0,044992] uvcvideo: Found UVC 1.00 device Piwebcam  (1d6b:0104)
[  +0,018794] uvcvideo 1-6:2.0: Entity type for entity Processing 2 was not initialized!
[  +0,000012] uvcvideo 1-6:2.0: Entity type for entity Camera 1 was not initialized!
[  +0,000239] input: Piwebcam : UVC Camera as /devices/pci0000:00/0000:00:14.0/usb1/1-6/1-6:2.0/input/input51
[  +0,001267] cdc_acm 1-6:2.2: ttyACM0: USB ACM device

[peterbay]

I have raspbian on rpi zero without any errors in dmesg. Maybe this problem is only in your distribution.

[dgsiegel]

I meant the dmesg output on the computer where you attach the pi. I just tested the following:

• Plug in a USB cable to the Power port
• Let it boot
• Attach a different USB cable to the data port and a computer

The result is that the device descriptor error goes away. So it seems that this is likely an issue with libcomposite/dwc and a race condition when booting.

[dgsiegel]

Can't reproduce this with a recent showmewebcam image