FTDI FT232R problem: failed to get modem status: -32

Hi,

I am using a USB->RS232 cable with an FTDI chip inside on a Arduino Yun processor. I installed the kmod-usb-serial-ftdi package and the driver sets up /dev/ttyUSB0 correctly:

Mar 24 12:08:02 Arduino kern.info kernel: [ 556.580000] usb 1-1.1: new full-speed USB device number 6 using ehci-platform
Mar 24 12:08:02 Arduino kern.info kernel: [ 556.710000] usb 1-1.1: New USB device found, idVendor=0403, idProduct=6001
Mar 24 12:08:02 Arduino kern.info kernel: [ 556.710000] usb 1-1.1: New USB device strings: Mfr=1, Product=2, SerialNumber=0
Mar 24 12:08:02 Arduino kern.info kernel: [ 556.710000] usb 1-1.1: Product: USB <-> Serial
Mar 24 12:08:02 Arduino kern.info kernel: [ 556.710000] usb 1-1.1: Manufacturer: FTDI
Mar 24 12:08:02 Arduino kern.info kernel: [ 556.720000] ftdi_sio 1-1.1:1.0: FTDI USB Serial Device converter detected
Mar 24 12:08:02 Arduino kern.info kernel: [ 556.720000] usb 1-1.1: Detected FT232BM
Mar 24 12:08:02 Arduino kern.info kernel: [ 556.720000] usb 1-1.1: Number of endpoints 2
Mar 24 12:08:02 Arduino kern.info kernel: [ 556.730000] usb 1-1.1: Endpoint 1 MaxPacketSize 16384
Mar 24 12:08:02 Arduino kern.info kernel: [ 556.730000] usb 1-1.1: Endpoint 2 MaxPacketSize 16384
Mar 24 12:08:02 Arduino kern.info kernel: [ 556.730000] usb 1-1.1: Setting MaxPacketSize 64
Mar 24 12:08:02 Arduino kern.info kernel: [ 556.740000] usb 1-1.1: FTDI USB Serial Device converter now attached to ttyUSB0

I set the port as follows:

speed 9600 baud; rows 0; columns 0; line = 0;
intr = ^C; quit = ^; erase = ^?; kill = ^U; eof = ^D; eol = ; eol2 = ; swtch = ; start = ^Q; stop = ^S; susp = ^Z;
rprnt = ^R; werase = ^W; lnext = ^V; flush = ^O; min = 0; time = 0;
-parenb -parodd cs8 hupcl -cstopb cread clocal -crtscts
-ignbrk -brkint -ignpar -parmrk -inpck -istrip -inlcr -igncr -icrnl -ixon -ixoff -iuclc -ixany -imaxbel -iutf8
-opost -olcuc -ocrnl -onlcr -onocr -onlret -ofill -ofdel nl0 cr0 tab0 bs0 vt0 ff0
-isig -icanon -iexten -echo -echoe -echok -echonl noflsh -xcase -tostop -echoprt -echoctl -echoke

However I get the following error after about a minute of usage:

Mar 24 12:10:53 Arduino kern.err kernel: [ 728.220000] ftdi_sio ttyUSB0: failed to get modem status: -32

I would be very grateful if anyone could help. This is a show stopper for my project!

Thanks,
Graham

USB port of Yun only outputs 4.48 volt.

IC FT232R working DC voltage is 5.5V~4.5V, Please use powered USB hub between FT232R and Yun.