[Answered] DevKitC: USB serial error returned on Linux - urb stopped: -32

[kolban]

I am running a Raspberry Pi connected by USB to DevKitC. This causes the serial port called /dev/ttyUSB0 to appear on the Pi. I am able to read the serial output from DevKitC from here just fine. However, non-deterministically ... after a few seconds, minutes or longer, we get a read error. Digging into /var/log/kern.log, I find an error logged as:

Code: Select all

cp210x ttyUSB0: usb_serial_generic_read_bulk_callback - urb stopped: -32

Here is an extract ... we can see this happen in the trace below:

Code: Select all

Sep 25 14:29:05 raspi3 kernel: [74221.763064] usb 1-1.4: USB disconnect, device number 60
Sep 25 14:29:05 raspi3 kernel: [74221.763654] cp210x ttyUSB0: cp210x converter now disconnected from ttyUSB0
Sep 25 14:29:05 raspi3 kernel: [74221.763723] cp210x 1-1.4:1.0: device disconnected
Sep 25 14:29:05 raspi3 kernel: [74222.003816] usb 1-1.4: new full-speed USB device number 61 using dwc_otg
Sep 25 14:29:05 raspi3 kernel: [74222.111547] usb 1-1.4: New USB device found, idVendor=10c4, idProduct=ea60
Sep 25 14:29:05 raspi3 kernel: [74222.111570] usb 1-1.4: New USB device strings: Mfr=1, Product=2, SerialNumber=3
Sep 25 14:29:05 raspi3 kernel: [74222.111583] usb 1-1.4: Product: CP2102 USB to UART Bridge Controller
Sep 25 14:29:05 raspi3 kernel: [74222.111596] usb 1-1.4: Manufacturer: Silicon Labs
Sep 25 14:29:05 raspi3 kernel: [74222.111608] usb 1-1.4: SerialNumber: 0001
Sep 25 14:29:05 raspi3 kernel: [74222.118305] cp210x 1-1.4:1.0: cp210x converter detected
Sep 25 14:29:05 raspi3 kernel: [74222.118757] usb 1-1.4: cp210x converter now attached to ttyUSB0
Sep 25 15:08:47 raspi3 kernel: [76603.842458] cp210x ttyUSB0: usb_serial_generic_read_bulk_callback - urb stopped: -32
Sep 25 15:08:47 raspi3 kernel: [76603.842544] cp210x ttyUSB0: usb_serial_generic_read_bulk_callback - urb stopped: -32
Sep 25 15:08:47 raspi3 kernel: [76603.904679] usb 1-1.4: USB disconnect, device number 61
Sep 25 15:08:47 raspi3 kernel: [76603.905347] cp210x ttyUSB0: cp210x converter now disconnected from ttyUSB0
Sep 25 15:08:47 raspi3 kernel: [76603.905405] cp210x 1-1.4:1.0: device disconnected
Sep 25 15:08:47 raspi3 kernel: [76604.143075] usb 1-1.4: new full-speed USB device number 62 using dwc_otg
Sep 25 15:08:47 raspi3 kernel: [76604.250897] usb 1-1.4: New USB device found, idVendor=10c4, idProduct=ea60
Sep 25 15:08:47 raspi3 kernel: [76604.250921] usb 1-1.4: New USB device strings: Mfr=1, Product=2, SerialNumber=3
Sep 25 15:08:47 raspi3 kernel: [76604.250935] usb 1-1.4: Product: CP2102 USB to UART Bridge Controller
Sep 25 15:08:47 raspi3 kernel: [76604.250948] usb 1-1.4: Manufacturer: Silicon Labs
Sep 25 15:08:47 raspi3 kernel: [76604.250960] usb 1-1.4: SerialNumber: 0001
Sep 25 15:08:47 raspi3 kernel: [76604.257990] cp210x 1-1.4:1.0: cp210x converter detected
Sep 25 15:08:47 raspi3 kernel: [76604.258521] usb 1-1.4: cp210x converter now attached to ttyUSB0

[WiFive]

If you Google it you will see others have had this problem with different chipsets such as ftdi and prolific too. Only bandaid fix I have seen is to force USB 1.1 speed.

[johnabel]

Same problem here. Curiously, it was working fine on a VM with Ubuntu 16, moved on 17.04 and ta-dah, got that!

Additionally, I forgot to add myself to the dialout group to access the port.