disable usb device in Debian Linux on Dell Latitude E7440

There is an infinite error message for

Bus 001 Device 114: ID 04f3:0111 Elan Microelectronics Corp.

Jan  7 01:04:10 e7440 kernel: [ 9561.564950] usb 1-1.8: Manufacturer: ELAN
Jan  7 01:04:12 e7440 kernel: [ 9563.570637] usb 1-1.8: USB disconnect, device number 32
Jan  7 01:04:12 e7440 kernel: [ 9563.768250] usb 1-1.8: new full-speed USB device number 33 using ehci_hcd
Jan  7 01:04:12 e7440 kernel: [ 9563.865866] usb 1-1.8: New USB device found, idVendor=04f3, idProduct=0111
Jan  7 01:04:12 e7440 kernel: [ 9563.865869] usb 1-1.8: New USB device strings: Mfr=4, Product=14, SerialNumber=0
Jan  7 01:04:12 e7440 kernel: [ 9563.865872] usb 1-1.8: Product: Touchscreen
Jan  7 01:04:12 e7440 kernel: [ 9563.865873] usb 1-1.8: Manufacturer: ELAN
Jan  7 01:04:15 e7440 kernel: [ 9565.871561] usb 1-1.8: USB disconnect, device number 33
Jan  7 01:04:15 e7440 kernel: [ 9566.069174] usb 1-1.8: new full-speed USB device number 34 using ehci_hcd
Jan  7 01:04:15 e7440 kernel: [ 9566.162795] usb 1-1.8: New USB device found, idVendor=04f3, idProduct=0111
Jan  7 01:04:15 e7440 kernel: [ 9566.162798] usb 1-1.8: New USB device strings: Mfr=4, Product=14, SerialNumber=0
Jan  7 01:04:15 e7440 kernel: [ 9566.162801] usb 1-1.8: Product: Touchscreen
Jan  7 01:04:15 e7440 kernel: [ 9566.162802] usb 1-1.8: Manufacturer: ELAN
Jan  7 01:04:17 e7440 kernel: [ 9568.172485] usb 1-1.8: USB disconnect, device number 34
Jan  7 01:04:17 e7440 kernel: [ 9568.370099] usb 1-1.8: new full-speed USB device number 35 using ehci_hcd
Jan  7 01:04:17 e7440 kernel: [ 9568.463719] usb 1-1.8: New USB device found, idVendor=04f3, idProduct=0111
Jan  7 01:04:17 e7440 kernel: [ 9568.463722] usb 1-1.8: New USB device strings: Mfr=4, Product=14, SerialNumber=0
Jan  7 01:04:17 e7440 kernel: [ 9568.463724] usb 1-1.8: Product: Touchscreen
Jan  7 01:04:17 e7440 kernel: [ 9568.463726] usb 1-1.8: Manufacturer: ELAN
Jan  7 01:04:19 e7440 kernel: [ 9570.473408] usb 1-1.8: USB disconnect, device number 35
Jan  7 01:04:19 e7440 kernel: [ 9570.671022] usb 1-1.8: new full-speed USB device number 36 using ehci_hcd
Jan  7 01:04:19 e7440 kernel: [ 9570.764643] usb 1-1.8: New USB device found, idVendor=04f3, idProduct=0111
Jan  7 01:04:19 e7440 kernel: [ 9570.764646] usb 1-1.8: New USB device strings: Mfr=4, Product=14, SerialNumber=0
Jan  7 01:04:19 e7440 kernel: [ 9570.764648] usb 1-1.8: Product: Touchscreen
Jan  7 01:04:19 e7440 kernel: [ 9570.764650] usb 1-1.8: Manufacturer: ELAN
Jan  7 01:04:21 e7440 kernel: [ 9572.774332] usb 1-1.8: USB disconnect, device number 36

So it eats up the computer resource and is writing its log into several files, e.g. kern.log and messages. It can be off by using the
following command

echo "0" > "/sys/bus/usb/devices/1-1.8/power/autosuspend_delay_ms" && echo "auto" > "/sys/bus/usb/devices/1-1.8/power/control" 

Check the following references :

http://forums.debian.net/viewtopic.php?f=7&t=104919

http://unix.stackexchange.com/questions/91027/how-to-disable-usb-autosuspend-on-kernel-3-7-10-or-above