To whom it may concern: I am having trouble with the Silicon Labs CP2105 (usb serial driver cp210x) enumerating both USB interfaces. When the CP2105-EK evaluation board is connected to the PC, Linux only creates a `/dev/ttyUSB0` device, but no `/dev/ttyUSB1` device is created. Upon unplugging the device and plugging it back in, Linux will correctly create both the `/dev/ttyUSB0` and `/dev/ttyUSB1` devices. I am wondering if this might be a driver issue. Can you give me any pointers? Here is a snippet of `/var/log/syslog`: May 6 15:59:31 dev kernel: [95779.749718] usb 1-2: new full-speed USB device number 4 using ohci_hcd May 6 15:59:32 dev kernel: [95780.222386] usb 1-2: New USB device found, idVendor=10c4, idProduct=ea70 May 6 15:59:32 dev kernel: [95780.222404] usb 1-2: New USB device strings: Mfr=1, Product=2, SerialNumber=5 May 6 15:59:32 dev kernel: [95780.222418] usb 1-2: Product: CP2105 Dual USB to UART Bridge Controller May 6 15:59:32 dev kernel: [95780.222432] usb 1-2: Manufacturer: Silicon Labs May 6 15:59:32 dev kernel: [95780.222588] usb 1-2: SerialNumber: 002D0751 May 6 15:59:32 dev kernel: [95780.267978] usbcore: registered new interface driver usbserial May 6 15:59:32 dev kernel: [95780.268002] USB Serial support registered for generic May 6 15:59:32 dev kernel: [95780.268008] usbcore: registered new interface driver usbserial_generic May 6 15:59:32 dev kernel: [95780.268552] usbserial: USB Serial Driver core May 6 15:59:32 dev kernel: [95780.270777] USB Serial support registered for cp210x May 6 15:59:32 dev kernel: [95780.270806] cp210x 1-2:1.0: cp210x converter detected May 6 15:59:32 dev kernel: [95780.669352] usb 1-2: reset full-speed USB device number 4 using ohci_hcd May 6 15:59:33 dev kernel: [95781.268311] usb 1-2: cp210x converter now attached to ttyUSB0 May 6 15:59:33 dev kernel: [95781.268354] cp210x 1-2:1.1: cp210x converter detected May 6 15:59:33 dev kernel: [95781.268536] cp210x ttyUSB0: cp210x converter now disconnected from ttyUSB0 May 6 15:59:33 dev kernel: [95781.268573] cp210x 1-2:1.0: device disconnected May 6 15:59:33 dev kernel: [95781.664834] usb 1-2: reset full-speed USB device number 4 using ohci_hcd May 6 15:59:34 dev kernel: [95782.192643] usb 1-2: cp210x converter now attached to ttyUSB0 May 6 15:59:34 dev kernel: [95782.193768] usbcore: registered new interface driver cp210x May 6 15:59:34 dev kernel: [95782.193783] cp210x: v0.09:Silicon Labs CP210x RS232 serial adaptor driver Then, I unplug the device and plug it back in.... May 6 16:00:05 dev kernel: [95813.481356] usb 1-2: USB disconnect, device number 4 May 6 16:00:05 dev kernel: [95813.481875] cp210x ttyUSB0: cp210x converter now disconnected from ttyUSB0 May 6 16:00:05 dev kernel: [95813.481914] cp210x 1-2:1.1: device disconnected May 6 16:00:12 dev kernel: [95820.484792] usb 1-2: new full-speed USB device number 5 using ohci_hcd May 6 16:00:12 dev kernel: [95820.959247] usb 1-2: New USB device found, idVendor=10c4, idProduct=ea70 May 6 16:00:12 dev kernel: [95820.959265] usb 1-2: New USB device strings: Mfr=1, Product=2, SerialNumber=5 May 6 16:00:12 dev kernel: [95820.959279] usb 1-2: Product: CP2105 Dual USB to UART Bridge Controller May 6 16:00:12 dev kernel: [95820.959292] usb 1-2: Manufacturer: Silicon Labs May 6 16:00:12 dev kernel: [95820.959305] usb 1-2: SerialNumber: 002D0751 May 6 16:00:12 dev kernel: [95820.965198] cp210x 1-2:1.0: cp210x converter detected May 6 16:00:13 dev kernel: [95821.369406] usb 1-2: reset full-speed USB device number 5 using ohci_hcd May 6 16:00:13 dev kernel: [95821.925765] usb 1-2: cp210x converter now attached to ttyUSB0 May 6 16:00:13 dev kernel: [95821.927820] cp210x 1-2:1.1: cp210x converter detected May 6 16:00:13 dev kernel: [95821.928959] cp210x ttyUSB0: cp210x converter now disconnected from ttyUSB0 May 6 16:00:13 dev kernel: [95821.929002] cp210x 1-2:1.0: device disconnected May 6 16:00:14 dev kernel: [95822.324582] usb 1-2: reset full-speed USB device number 5 using ohci_hcd May 6 16:00:14 dev kernel: [95822.903592] cp210x 1-2:1.0: cp210x converter detected May 6 16:00:15 dev kernel: [95823.301631] usb 1-2: reset full-speed USB device number 5 using ohci_hcd May 6 16:00:15 dev kernel: [95823.889378] usb 1-2: cp210x converter now attached to ttyUSB0 May 6 16:00:15 dev kernel: [95823.892031] usb 1-2: cp210x converter now attached to ttyUSB1 I am running Debian Linux 7 (with Linux kernel 3.2.0-4-amd64). I have tried the built-in Debian kernel driver and SiLabs's driver (http://www.silabs.com/Support%20Documents/Software/Linux_3.x.x_VCP_Driver_Source.zip). Both behave the same way. Also, I found out that running `modprobe cp210x` before plugging in the device will properly register both interfaces (`ttyUSB0` and `ttyUSB1`). It would appear that the driver must be completely loaded before the device can be properly detected. Any thoughts on this? Thanks, Blake -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
