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  1. #1

    PCIe IOMEM Resource Allocation


    Hi
    I am trying to write a PCIe linux device driver to handle PCIe switches and endpoints that show up after the Redhat 6.4 linux is already up and running.

    If I try to allocate the resources of the PCIe switches & endpoints between 0xF4000000 and 0xF47FFFFF everything works fine .. But this range is quite full with other devices, so I tried to extend this range to start from 0xF0000000, or from 0xD0000000 the allocation works fine, but I am unable to access devices in the extended range

    Anybody has idea why I am unable to use the complete 3G - 4G address range ?
    Is it related to some ACPI boot configuration that need to be changed, I can see in my dmesg

    pci_root PNP0A08:00: host bridge window [mem 0xf4000000-0xf7ffffff]
    pci_root PNP0A08:00: host bridge window [io 0x1000-0x7fff]
    pci_root PNP0A08:00: host bridge window [io 0x0000-0x03af]
    pci_root PNP0A08:00: host bridge window [io 0x03e0-0x0cf7]
    pci_root PNP0A08:00: host bridge window [io 0x0d00-0x0fff]
    pci_root PNP0A08:00: host bridge window [mem 0xfed00000-0xfed03fff]
    pci_root PNP0A08:00: host bridge window [mem 0xfed40000-0xfed44fff]
    pci_root PNP0A08:00: host bridge window [io 0x03b0-0x03bb]
    pci_root PNP0A08:00: host bridge window [io 0x03c0-0x03df]
    pci_root PNP0A08:00: host bridge window [mem 0x000a0000-0x000bffff]
    pci_root PNP0A08:01: host bridge window [mem 0xf8000000-0xfbffffff]
    pci_root PNP0A08:01: host bridge window [io 0x8000-0xffff]

    Is there a reason for this limited range ? Is it processor dependant ?

    Thanks

  2. #2
    Linux Guru Rubberman's Avatar
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    I would suggest going to the forums at www.kernel.org and asking there. This is very specialized knowledge, and I don't know how many of us can answer the question. I can't and I have been working with Linux systems for 15 years, including device driver development...
    Sometimes, real fast is almost as good as real time.
    Just remember, Semper Gumbi - always be flexible!

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