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  1. #1

    USB Host Configuration in kernel


    Hi All,

    I have configured Linux 2.6.30 for USB Host, and my /dev directory have /dev/sda /dev/sda1 and /dev/sda2 as part of my filesystem.

    When I connect pendrive for the first time, kernel says its there on sda:sda1. I can mount it on XYZ directory.

    Now if i remove pendrive without applying un mounting it next time kernel says me usb is mounted on sdb:sdb1
    but there is no /dev node created like /dev/sdb /dev/sdb1 etc.

    My question is, It it responsibility of kernel to make this nodes?

    Or I have left some option while configuring kernel ??

  2. #2
    hi,

    it is usually the job of the udev daemon to detect hotplug events and create kernel devices for you. It could be that things work with sda b/c that block device was already created and you have no udev process controlling it, and no sdb device has ever been created.

    At least it is udev on the (RedHat/Fedora/CentOS) systems that I normally use. What is your distro and version?
    Last edited by atreyu; 08-06-2013 at 02:55 AM. Reason: typo

  3. #3
    Hi!! Thanx!!

    I am actually working on at91sam9g45 based Evaluation Board.
    In which my platform will serve as USB host and not for USB device.

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  5. #4
    Quote Originally Posted by elementm View Post
    I am actually working on at91sam9g45 based Evaluation Board.
    In which my platform will serve as USB host and not for USB device.
    i see, so your eval board can be plugged into a PC or something, and that PC should see the eval board as USB storage, or something like that? in that case, you don't need sda/sdb, etc. you only need those when you are booting into the eval board as a stand-alone Linux system, right? In that case, do you have udev installed on that system?

  6. #5
    No No .. My Eval board has usb port which I needed to configure as usb host.
    When I plug usb on my eval board, there is no /dev/sd* entry but in dmesg kernel says your device is there on sda:sda1 etc.

    Than You for your help and suggestions.

    I have cross compiled udev-144 and ran on my eval board and now its making /dev/sd* entries..
    I have simply copied 50rules file to /etc/udev/rules.d/ and ran ran udevd and problem resolved.

    Thank You.

  7. #6
    great, glad its sorted. i'll mark this as Solved for you. Note that you can do this yourself using the Thread Tools link at the top of the page.

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