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Last Post 23 Sep 2005 12:53 AM by  hatzfeld
rcu_dereference() return NULL pointer
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overet
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01 Sep 2005 05:44 AM
    Hi,
    i have a problem with the linux kernel non PCS 2.6.10 version. The Bridge module not works properly on the coldfire arch. I seen that it have a problem with rcu_dereference() function, that return a NULL pointer while it shouldn't.

    Do you have found the same problem in some situation?

    Best regards,
    Giuseppe Gottardi
    Anonymous
    Posts:


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    15 Sep 2005 02:24 PM
    Hello Guiseppe,

    This is a third party Linux BSP from Metrowerks and is not directly supported by Logic so there aren't any developers at Logic that have worked with the BSP. I would recommend contacting Metrowerks or Freescale for support on working with this BSP.

    However there is a Linux sample image that is now available on the downloads page to let customers evaluate the Logic Linux BSP that will be released and supported by Logic. You can download this image here depending on the platform you are using.

    5475:
    http://www.logicpd.com/do...nux_demo_1_m5475.zip

    5485:
    http://www.logicpd.com/do...nux_demo_1_m5485.zip

    And use with the "Zoom CDK Linux Evaluation Guide":

    http://www.logicpd.com/do...90/1003255_Rev_A.pdf

    Regards,
    hatzfeld
    New Member
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    16 Sep 2005 02:30 AM
    I use the 2.6 non PCS but I believe it's not a problem of this.
    If no pci card is fitted lspci shows the builtin devices (bridge usbhost display)
    if I plug in any kind of pci card no matter what kind and no matter what kind of power supply best thing that happens is the system is booting and a lspci shows only the topmost device which is the coldfire builtin bridge I guess.

    For testing I used a realtek 8139 ethernet card (ammong several other cards I had in my cabinet) which is natively supported by the kernel. Real arget is a rt2500 wi-fi card.

    Is there really a working pci card with running linux drivers no matter what type I can buy at a computer store from shelf to test my hardware?

    I start to believe there is a bug in the hardware (Zoom CDK Rev B shipped this summer) and / or in the coldfire pci drivers.

    Is there any known way to get one of the onboard pci devices running under linux?

    Funny thing: The new linux demo states to have no pci support and later in the same text tells you to make a lspci. Also fitting in any pci cards is not recommended. That exactly sounds like my problem...

    Falk
    sams@nospamlogicpd.com
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    New Member
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    16 Sep 2005 10:57 AM
    Falk,

    Have you seen the PCI errata off of Freescales website?

    Here's one for the MCF5485, I think it's pretty similiar across processors in Logic's Coldfire products:

    http://www.freescale.com/...errata/MCF5485DE.pdf

    We've been having PCI issues in our linux development too due to these. Let me know if you have any more questions. Thanks for pointing that out with our doc too.

    Sam Siciliano
    Logic Product Development
    hatzfeld
    New Member
    New Member
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    19 Sep 2005 02:47 AM
    Sam,
    thank you for this hint. Same issues seem to apply to the assembled 5475 Code L14S. I've no detailed knowledge about pci so it's hard for me to weigh the importance of these issues.
    Still my question is open and should be easy for you as the EVB manufacturer to reply. Is the PCI on the zoom board operational? Operational with Linux? What is a setup to test it?
    I'm sure you did some lab tests before going into production.

    Falk
    sams@nospamlogicpd.com
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    19 Sep 2005 05:54 PM
    Falk,

    To answer your questions:

    Quote:
    Is the PCI on the zoom board operational? Operational with Linux? What is a setup to test it?


    For the first question, yes. We've verified PCI peripherals using custom test software we've developed. The tests applications were not within a Linux OS however. You should be able to see the RTL712GE PCI video controllor work in our bootloader LoLo (available off our website) by using the "video-open" and "draw-test" commands.

    Just to check, are these PCI cards you're trying to use 3.3V or 5.0V cards?
    hatzfeld
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    23 Sep 2005 12:53 AM
    I finally got some cards recognized by lspci. Then I tried to use them by compiling / modprobing the needed drivers (rt2500, 8139too). Freezes linux. Seems to be a problem of the BSP. I will ask the folks at the metrowerks community about this. Too sad I dindn't manage to get a wifi card with the chipset mentioned in the documentation.

    Falk
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