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FTDI USB to serial converter problem ftdi_set_termios FAILED to set databits/stopbits/parity

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qiz
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FTDI USB to serial converter problem ftdi_set_termios FAILED to set databits/stopbits/parity

qiz
hi all:

I am trying to connect several usb to serial converters to my Gumstix overo over the USB OTG port by utilizing the Belkin USB hub.  I am using two PL2303 and one FTDI chip, the file for FTDI chip is ttyUSB0.

Here is the output of dmesg | grep ttyU

usb 1-1.1: pl2303 converter now attached to ttyUSB1
usb 1-1.3: FTDI USB Serial Device converter now attached to ttyUSB0
usb 1-1.2: pl2303 converter now attached to ttyUSB2

My problems is that when I try to open ttyUSB0 the second time after reboot, I get this kind of error:

ftdi_sio ttyUSB0: ftdi_set_termios FAILED to set databits/stopbits/parity
ftdi_sio ttyUSB0: ftdi_set_termios urb failed to set baudrate
ftdi_sio ttyUSB0: urb failed to clear flow control
But it can still work (receive and send data),  then after I open this file (ttyUSB0) and close it several times, this usb to serial port just stop working.

I did the same operation to  ttyUSB1 and ttyUSB2, which are using the pl2303 chip, and they don't have any error.

I tried to install the following package:
 opkg install kernel-module-ftdi-sio
Package kernel-module-ftdi-sio (3.0-r103.6) installed in root is up to date.

here is the out put of  lsusb

lsusb
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 002: ID 05e3:0608 Genesys Logic, Inc. USB-2.0 4-Port HUB
Bus 001 Device 003: ID 067b:2303 Prolific Technology, Inc. PL2303 Serial Port
Bus 001 Device 004: ID 067b:2303 Prolific Technology, Inc. PL2303 Serial Port
Bus 001 Device 005: ID 0403:6001 Future Technology Devices International, Ltd FT232 USB-Serial (UART) IC
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub


Does any one know how to fix this problem?   I cannot use a third PL2303 because I need a serial at TTL level, not RS232.

Thanks very much in advance!!!






qiz
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Re: FTDI USB to serial converter problem ftdi_set_termios FAILED to set databits/stopbits/parity

qiz
Hi
I have figured out my problem by switch the usb hub to a powered one.  All of a sudden everything works fine.
So the conclusion is that even if your devices are powered separately, the USB OTG port can still only drive one connection. If you want to connect more than two usb connection to the USB OTG port by a usb hub, you need to power the USB hub separetely.
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