USB attached memory card reader weirdness - Linux

This is a discussion on USB attached memory card reader weirdness - Linux ; When I boot the Ubuntu 6.06 LTS disc, which requires that I add the option "noapic" to succeed (else the kernel panics), it does successfully see both my CF and my SD cards which are plugged into a memory card ...

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Thread: USB attached memory card reader weirdness

  1. USB attached memory card reader weirdness

    When I boot the Ubuntu 6.06 LTS disc, which requires that I add the option
    "noapic" to succeed (else the kernel panics), it does successfully see both
    my CF and my SD cards which are plugged into a memory card reader that uses
    oen USB connection. I have a SATA drive which comes up as sda. The CF is
    seen as sdb and the SD is seen as sde. I assume sdc and sdd would be for
    the other card slots I don't use.

    When I boot my own compiled kernel, it sees the CF card OK at sdb. But the
    SD card does not show up at all.

    Both situations were tested with both a regular SD card (2GB) and an SDHC
    card (4GB). Both SD and SDHC work when either work, and both fail when
    either fail.

    The CF card is 2GB.

    So why would there be a difference between one slot and another with respect
    to the kernel (which might be a version issue or a configuration issue)?
    I would think the card reader is merely emulating a USB storage device on
    the USB bus. Why would one of the cards show up and not the other in one
    case (my compiled kernel) and both show up in the other case (Ubuntu)?
    I suppose I should dig in and see if I can find the .config for Ubuntu.
    But even if there is a difference, that just doesn't make sense why there
    would be one for this kind of thing.

    Is this kind of thing (various storage devices connected via USB) truly
    doing a storage abstraction, or is there a lot of detail about the device
    that the kernel has to handle (and therefore be configured to handle)?

    --
    |---------------------------------------/----------------------------------|
    | Phil Howard KA9WGN (ka9wgn.ham.org) / Do not send to the address below |
    | first name lower case at ipal.net / spamtrap-2008-01-02-1833@ipal.net |
    |------------------------------------/-------------------------------------|

  2. Re: USB attached memory card reader weirdness

    phil-news-nospam@ipal.net wrote:

    > When I boot my own compiled kernel, it sees the CF card OK at
    > sdb. But the SD card does not show up at all.


    Configure the SCSI subsystem to support scanning for multiple
    LUNs. The card reader appears as a single SCSI device, and the
    slots as LUNs of that device.

    Wolfgang Draxinger
    --
    E-Mail address works, Jabber: hexarith@jabber.org, ICQ: 134682867


  3. Re: USB attached memory card reader weirdness

    On Thu, 03 Jan 2008 10:38:31 +0100 Wolfgang Draxinger wrote:

    | phil-news-nospam@ipal.net wrote:
    |
    |> When I boot my own compiled kernel, it sees the CF card OK at
    |> sdb. But the SD card does not show up at all.
    |
    | Configure the SCSI subsystem to support scanning for multiple
    | LUNs. The card reader appears as a single SCSI device, and the
    | slots as LUNs of that device.

    Interesting. That doesn't happen on some other machines. I guess the way
    it gets done depends on whose card reader implementation it is. I do have
    one that creates distinct USB storage devices for each card slot. Another
    creates one device, limits to only one card at a time, and make whatever
    card slot is in use be that device. I guess no two engineers are alike :-)

    Thanks.

    --
    -----------------------------------------------------------------------------
    | Phil Howard KA9WGN | http://linuxhomepage.com/ http://ham.org/ |
    | (first name) at ipal.net | http://phil.ipal.org/ http://ka9wgn.ham.org/ |
    -----------------------------------------------------------------------------

  4. Re: USB attached memory card reader weirdness

    On 6 Jan 2008 08:27:30 GMT phil-news-nospam@ipal.net wrote:

    | On Thu, 03 Jan 2008 10:38:31 +0100 Wolfgang Draxinger wrote:
    |
    | | phil-news-nospam@ipal.net wrote:
    | |
    | |> When I boot my own compiled kernel, it sees the CF card OK at
    | |> sdb. But the SD card does not show up at all.
    | |
    | | Configure the SCSI subsystem to support scanning for multiple
    | | LUNs. The card reader appears as a single SCSI device, and the
    | | slots as LUNs of that device.
    |
    | Interesting. That doesn't happen on some other machines. I guess the way
    | it gets done depends on whose card reader implementation it is. I do have
    | one that creates distinct USB storage devices for each card slot. Another
    | creates one device, limits to only one card at a time, and make whatever
    | card slot is in use be that device. I guess no two engineers are alike :-)
    |
    | Thanks.

    And a confirmation: Yes, this does solve the problem. Thanks, again.

    --
    -----------------------------------------------------------------------------
    | Phil Howard KA9WGN | http://linuxhomepage.com/ http://ham.org/ |
    | (first name) at ipal.net | http://phil.ipal.org/ http://ka9wgn.ham.org/ |
    -----------------------------------------------------------------------------

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