I am using Beagleboard-xm with 3.12 Kernel and ubuntu rootfs from Robert Nelson's site. I use a Telit HE910 GPS+GSM modem along with my project .So as per the HW user guide i have to apply a logic high for 5s on the input of this modem for enabling it So when I does this by toggling the gpio pin for 5s using a script I'm getting some messages on the terminal I am sure this message comes from the driver in usb/class/cdc-acm.c but couldn't find the reason behind this? How can I solve this issue?? root@arm:~# ./modem_on.sh Turning on Telit modem ...... going to sleep and toggle [ 70.791381] cdc_acm 1-2:1.0: This device cannot do calls on its own. It is not a modem. [ 74.390258] cdc_acm 1-2:1.0: This device cannot do calls on its own. It is not a modem. [ 74.406890] cdc_acm 1-2:1.2: This device cannot do calls on its own. It is not a modem. [ 74.462188] cdc_acm 1-2:1.4: This device cannot do calls on its own. It is not a modem. [ 74.478363] cdc_acm 1-2:1.6: This device cannot do calls on its own. It is not a modem. [ 74.495269] cdc_acm 1-2:1.8: This device cannot do calls on its own. It is not a modem. [ 74.510040] cdc_acm 1-2:1.10: This device cannot do calls on its own. It is not a modem. [ 74.530090] cdc_acm 1-2:1.12: This device cannot do calls on its own. It is not a modem. [ 74.619720] cdc_acm 1-2:1.0: This device cannot do calls on its own. It is not a modem. [ 74.634429] cdc_acm 1-2:1.2: This device cannot do calls on its own. It is not a modem. [ 74.649475] cdc_acm 1-2:1.4: This device cannot do calls on its own. It is not a modem. [ 74.664459] cdc_acm 1-2:1.6: This device cannot do calls on its own. It is not a modem. [ 74.678741] cdc_acm 1-2:1.8: This device cannot do calls on its own. It is not a modem. [ 74.693389] cdc_acm 1-2:1.10: This device cannot do calls on its own. It is not a modem. [ 74.708099] cdc_acm 1-2:1.12: This device cannot do calls on its own. It is not a modem. Script complete .......... The realted necessary portion of dmesg is below [ 30.623107] init: plymouth-upstart-bridge main process ended, respawning [ 70.629943] usb 1-2: new high-speed USB device number 2 using ehci-omap [ 70.782501] usb 1-2: config 1 interface 0 altsetting 0 endpoint 0x81 has an invalid bInterval 255, changing to 11 [ 70.782592] usb 1-2: New USB device found, idVendor=058b, idProduct=0041 [ 70.782623] usb 1-2: New USB device strings: Mfr=0, Product=0, SerialNumber=0 [ 70.791381] cdc_acm 1-2:1.0: This device cannot do calls on its own. It is not a modem. [ 70.801483] cdc_acm 1-2:1.0: ttyACM0: USB ACM device [ 73.041625] usb 1-2: USB disconnect, device number 2 [ 74.209930] usb 1-2: new high-speed USB device number 3 using ehci-omap [ 74.369049] usb 1-2: New USB device found, idVendor=1bc7, idProduct=0021 [ 74.369110] usb 1-2: New USB device strings: Mfr=1, Product=2, SerialNumber=3 [ 74.369140] usb 1-2: Product: Telit Wireless Module [ 74.369171] usb 1-2: Manufacturer: Telit wireless solutions [ 74.369201] usb 1-2: SerialNumber: 357164042197668 [ 74.390258] cdc_acm 1-2:1.0: This device cannot do calls on its own. It is not a modem. [ 74.400207] cdc_acm 1-2:1.0: ttyACM0: USB ACM device [ 74.406890] cdc_acm 1-2:1.2: This device cannot do calls on its own. It is not a modem. [ 74.416900] cdc_acm 1-2:1.2: ttyACM1: USB ACM device [ 74.462188] cdc_acm 1-2:1.4: This device cannot do calls on its own. It is not a modem. [ 74.472259] cdc_acm 1-2:1.4: ttyACM2: USB ACM device [ 74.478363] cdc_acm 1-2:1.6: This device cannot do calls on its own. It is not a modem. [ 74.488372] cdc_acm 1-2:1.6: ttyACM3: USB ACM device [ 74.495269] cdc_acm 1-2:1.8: This device cannot do calls on its own. It is not a modem. [ 74.505279] cdc_acm 1-2:1.8: ttyACM4: USB ACM device [ 74.510040] cdc_acm 1-2:1.10: This device cannot do calls on its own. It is not a modem. [ 74.520141] cdc_acm 1-2:1.10: ttyACM5: USB ACM device [ 74.530090] cdc_acm 1-2:1.12: This device cannot do calls on its own. It is not a modem. [ 74.540283] cdc_acm 1-2:1.12: ttyACM6: USB ACM device [ 74.619720] cdc_acm 1-2:1.0: This device cannot do calls on its own. It is not a modem. [ 74.629455] cdc_acm 1-2:1.0: ttyACM0: USB ACM device [ 74.634429] cdc_acm 1-2:1.2: This device cannot do calls on its own. It is not a modem. [ 74.644042] cdc_acm 1-2:1.2: ttyACM1: USB ACM device [ 74.649475] cdc_acm 1-2:1.4: This device cannot do calls on its own. It is not a modem. [ 74.659027] cdc_acm 1-2:1.4: ttyACM2: USB ACM device [ 74.664459] cdc_acm 1-2:1.6: This device cannot do calls on its own. It is not a modem. [ 74.674133] cdc_acm 1-2:1.6: ttyACM3: USB ACM device [ 74.678741] cdc_acm 1-2:1.8: This device cannot do calls on its own. It is not a modem. [ 74.688415] cdc_acm 1-2:1.8: ttyACM4: USB ACM device [ 74.693389] cdc_acm 1-2:1.10: This device cannot do calls on its own. It is not a modem. [ 74.703186] cdc_acm 1-2:1.10: ttyACM5: USB ACM device [ 74.708099] cdc_acm 1-2:1.12: This device cannot do calls on its own. It is not a modem. [ 74.717895] cdc_acm 1-2:1.12: ttyACM6: USB ACM device `