strange usb behavior

[Jaap de Jong <jaap.dejong@nedap.com>]

Hi All!

I'm observing some strange usb behavior.
I have a board with an onboard ftdi usb chip acting as 2 rs232 ports.
And I have on the same board an external usb device with again a ftdi 
chip on board, this time acting as a single rs485 port.

    Build Configuration:
    BB_VERSION        = "1.8.18"
    METADATA_BRANCH   = "release-2010.12"
    METADATA_REVISION = "dec3967"
    TARGET_ARCH       = "arm"
    TARGET_OS         = "linux-gnueabi"
    MACHINE           = "at91sam9263ek-special"
    DISTRO            = "angstrom"
    DISTRO_VERSION    = "2010.7-test-20101210"
    TARGET_FPU        = "soft"

So when I boot with the external device in the connector the internal 
and external devices are detected as expected.

     [    1.280000] usb 1-1: new full speed USB device using at91_ohci 
and address 2
     [    1.460000] usb 1-1: configuration #1 chosen from 1 choice
     [    1.470000] ftdi_sio 1-1:1.0: FTDI USB Serial Device converter 
detected
     [    1.470000] usb 1-1: Detected FT2232C
     [    1.480000] usb 1-1: Number of endpoints 2
     [    1.480000] usb 1-1: Endpoint 1 MaxPacketSize 64
     [    1.490000] usb 1-1: Endpoint 2 MaxPacketSize 64
     [    1.490000] usb 1-1: Setting MaxPacketSize 64
     [    1.500000] usb 1-1: FTDI USB Serial Device converter now 
attached to ttyUSB0
     [    1.510000] ftdi_sio 1-1:1.1: FTDI USB Serial Device converter 
detected
     [    1.510000] usb 1-1: Detected FT2232C
     [    1.520000] usb 1-1: Number of endpoints 2
     [    1.520000] usb 1-1: Endpoint 1 MaxPacketSize 64
     [    1.530000] usb 1-1: Endpoint 2 MaxPacketSize 64
     [    1.530000] usb 1-1: Setting MaxPacketSize 64
     [    1.540000] usb 1-1: FTDI USB Serial Device converter now 
attached to ttyUSB1
     [    1.680000] usb 1-2: new full speed USB device using at91_ohci 
and address 3
     [    1.860000] usb 1-2: configuration #1 chosen from 1 choice
     [    1.870000] ftdi_sio 1-2:1.0: FTDI USB Serial Device converter 
detected
     [    1.880000] usb 1-2: Detected FT232RL
     [    1.880000] usb 1-2: Number of endpoints 2
     [    1.890000] usb 1-2: Endpoint 1 MaxPacketSize 64
     [    1.890000] usb 1-2: Endpoint 2 MaxPacketSize 64
     [    1.900000] usb 1-2: Setting MaxPacketSize 64
     [    1.900000] usb 1-2: FTDI USB Serial Device converter now 
attached to ttyUSB2


But if I look at the /dev directory ttyUSB2 is missing!

     # ls -l /dev/ttyU*
         crw-rw----    1 root     dialout  188,   0 Jan  1  1970 
/dev/ttyUSB0
         crw-rw----    1 root     dialout  188,   1 Jan  1  1970 
/dev/ttyUSB1

     # lsusb
         Bus 001 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
         Bus 001 Device 002: ID 0403:6010 Future Technology Devices 
International, Ltd FT2232C Dual USB-UART/FIFO IC
         Bus 001 Device 003: ID 0403:6001 Future Technology Devices 
International, Ltd FT232 USB-Serial (UART) IC

So, why is ttyUSB2 gone and are ttyUSB[01] still available??

If I then remove (mark the second line!)

     [  103.600000] usb 1-2: USB disconnect, address 3
     [  103.610000] ftdi_sio ttyUSB2: FTDI USB Serial Device converter 
now disconnected from ttyUSB2
     [  103.630000] ftdi_sio 1-2:1.0: device disconnected

and re-enter the external device life is OK!

     [  140.020000] usb 1-2: new full speed USB device using at91_ohci 
and address 4
     [  140.200000] usb 1-2: configuration #1 chosen from 1 choice
     [  140.230000] ftdi_sio 1-2:1.0: FTDI USB Serial Device converter 
detected
     [  140.250000] usb 1-2: Detected FT232RL
     [  140.250000] usb 1-2: Number of endpoints 2
     [  140.250000] usb 1-2: Endpoint 1 MaxPacketSize 64
     [  140.260000] usb 1-2: Endpoint 2 MaxPacketSize 64
     [  140.260000] usb 1-2: Setting MaxPacketSize 64
     [  140.270000] usb 1-2: FTDI USB Serial Device converter now 
attached to ttyUSB2

     # ls -l /dev/ttyU*
         crw-rw----    1 root     dialout  188,   0 Jan  1  1970 
/dev/ttyUSB0
         crw-rw----    1 root     dialout  188,   1 Jan  1  1970 
/dev/ttyUSB1
         crw-rw----    1 root     dialout  188,   2 Dec 10 02:18 
/dev/ttyUSB2

     # lsusb
         Bus 001 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
         Bus 001 Device 002: ID 0403:6010 Future Technology Devices 
International, Ltd FT2232C Dual USB-UART/FIFO IC
         Bus 001 Device 004: ID 0403:6001 Future Technology Devices 
International, Ltd FT232 USB-Serial (UART) IC

Any ideas??

Thanks!
Jaap