usbdev files - Hardware

This is a discussion on usbdev files - Hardware ; When a usb device is attached, entries with names like usbdev4.1_ep00 appear in /dev/ There appears to be one for every endpoint on every device attached. Does anyone know what these nodes are used for? Peter...

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  1. usbdev files

    When a usb device is attached, entries with names like usbdev4.1_ep00
    appear in /dev/ There appears to be one for every endpoint on every
    device attached.

    Does anyone know what these nodes are used for?

    Peter

  2. Re: usbdev files

    Peter Hull wrote:

    > When a usb device is attached, entries with names like usbdev4.1_ep00
    > appear in /dev/ There appears to be one for every endpoint on every
    > device attached.


    What device exactly are you talking about? A USB hub perhaps? A USB
    storage device with multiple LUNs?

    > Does anyone know what these nodes are used for?


    They exist so that processes with the proper permissions can communicate
    with the devices.

    Perhaps if you were being more verbose? What exactly did you plug in? Are
    the device special files listed as character devices or as block devices?

    --
    *Aragorn*
    (registered GNU/Linux user #223157)

  3. Re: usbdev files

    On Jun 5, 12:40*pm, Aragorn wrote:
    > Peter Hull wrote:
    > What device exactly are you talking about? *A USB hub perhaps? *A USB
    > storage device with multiple LUNs?


    As far as I know, any device (including internal hubs) - see below.
    This is not a problem, I'm just curious and I imagine that someone
    would just know what they are straight away.

    >
    > > Does anyone know what these nodes are used for?

    >
    > They exist so that processes with the proper permissions can communicate
    > with the devices.


    My question really is: are these files any use for communicating with
    a device from user space? I've seen documentation on the ioctl
    interface for the nodes in /dev/bus/usb/BBB/DDD (which is what libusb
    uses) but I've never seen anything on these files. I found the part in
    the source code where they're created but my knowledge is not enough
    to understand what they're for.

    >
    > Perhaps if you were being more verbose? *What exactly did you plug in? *Are
    > the device special files listed as character devices or as block devices?


    Here's the output from ls /dev/usb* on my system (Ubuntu 8.04 i386)
    crw-rw---- 1 root root 254, 0 2008-06-05 13:11 /dev/usbdev1.1_ep00
    crw-rw---- 1 root root 254, 1 2008-06-05 13:11 /dev/usbdev1.1_ep81
    crw-rw---- 1 root root 254, 2 2008-06-05 13:11 /dev/usbdev2.1_ep00
    crw-rw---- 1 root root 254, 3 2008-06-05 13:11 /dev/usbdev2.1_ep81
    crw-rw---- 1 root root 254, 4 2008-06-05 13:11 /dev/usbdev3.1_ep00
    crw-rw---- 1 root root 254, 5 2008-06-05 13:11 /dev/usbdev3.1_ep81
    crw-rw---- 1 root root 254, 6 2008-06-05 13:11 /dev/usbdev4.1_ep00
    crw-rw---- 1 root root 254, 7 2008-06-05 13:11 /dev/usbdev4.1_ep81
    crw-rw---- 1 root root 254, 8 2008-06-05 13:11 /dev/usbdev5.1_ep00
    crw-rw---- 1 root root 254, 9 2008-06-05 13:11 /dev/usbdev5.1_ep81
    crw-rw---- 1 root root 254, 10 2008-06-05 13:15 /dev/usbdev5.2_ep00
    crw-rw---- 1 root root 254, 12 2008-06-05 13:15 /dev/usbdev5.2_ep01
    crw-rw---- 1 root root 254, 11 2008-06-05 13:15 /dev/usbdev5.2_ep81

    Most of these are hubs (ID 0000:0000) apart from this one (output from
    lsusb)
    Bus 005 Device 002: ID 0781:5151 SanDisk Corp. Cruzer Micro 256/512MB
    Flash Drive
    So you can see how they match up.

    Pete
    >
    > --
    > *Aragorn*
    > (registered GNU/Linux user #223157)



  4. Re: usbdev files

    Peter Hull wrote:
    > When a usb device is attached, entries with names like usbdev4.1_ep00
    > appear in /dev/ There appears to be one for every endpoint on every
    > device attached.
    >
    > Does anyone know what these nodes are used for?


    You can get a lot of info about this from the book
    Essential Linux Device Drivers

    It goes into great detail with regards to USB (and other things).

    I can't remember exactly how the device is used though... I'd
    have to look it up really fast in the book.

    Probably some kind of control device (??)

  5. Re: usbdev files

    Chris Cox wrote:
    > Peter Hull wrote:
    >> When a usb device is attached, entries with names like usbdev4.1_ep00
    >> appear in /dev/ There appears to be one for every endpoint on every
    >> device attached.
    >>
    >> Does anyone know what these nodes are used for?

    >
    > You can get a lot of info about this from the book
    > Essential Linux Device Drivers
    >
    > It goes into great detail with regards to USB (and other things).
    >
    > I can't remember exactly how the device is used though... I'd
    > have to look it up really fast in the book.
    >
    > Probably some kind of control device (??)


    Actually endpoint 0 on each device is the control device... the
    rest are for various types of transfer, in/out, interrupts...

  6. Re: usbdev files

    On Jun 6, 4:44*am, Chris Cox wrote:
    > Chris Cox wrote:
    > > Peter Hull wrote:
    > >> When a usb device is attached, entries with names like usbdev4.1_ep00
    > >> appear in /dev/ There appears to be one for every endpoint on every
    > >> device attached.

    >
    > >> Does anyone know what these nodes are used for?

    >

    Eventually I found the linux-usb mailing list and asked there. The
    answer is that those nodes are just placeholders for future
    development and, at the moment, can't be used for anything. Thanks to
    everyone for their help.

    Peter


  7. Re: usbdev files

    Thanks, Peter.

    I was in the same problem, how can I tell which usb device storage is
    and where is the usb hdd dev in the UBUNTU?

    Now I must try other linux, like knoppix to get usb hdd storage.

    or, any updating UBUNTU could solve the usb hdd device ? (I'll try..)


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