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    SubjectRe: How can PCI resource allocation fail?
    Christian P. Schmidt wrote:
    > Hi all,
    >
    > I'm toying with the alsa-driver for the Creative Labs X-Fi. I'm working on the PCI Express version of this card, though, which is
    > the same as the PCI version plus a PCIe to PCI bridge but has a different ID:
    >
    > +-1c.2-[0000:03-04]----00.0-[0000:04]----00.0 1102:0009
    >
    > 03:00.0 PCI bridge: Creative Labs Device 7006
    > 04:00.0 Audio device: Creative Labs [SB X-Fi Xtreme Audio] CA0110-IBG
    >
    > Now, after adding the ID, the driver fails:
    >
    > [46833.487579] CA0106 0000:04:00.0: PCI INT A -> GSI 18 (level, low) -> IRQ 18
    > [46833.487586] CA0106 0000:04:00.0: PCI INT A disabled
    > [46833.487588] cannot allocate the port
    > [46833.487594] CA0106: probe of 0000:04:00.0 failed with error -16
    >
    > The actual error is occurring in
    >
    > chip->port = pci_resource_start(pci, 0);
    > chip->res_port = request_region(chip->port, pci_resource_len(pci,0), "snd_ca0106");
    > if (!chip->res_port) {
    > snd_ca0106_free(chip);
    > printk(KERN_ERR "cannot allocate the port\n");
    > return -EBUSY;
    > }
    >
    > This from /proc/iomem:
    >
    > f9f00000-f9ffffff : PCI Bus 0000:03
    > f9f00000-f9ffffff : PCI Bus 0000:04
    > f9ffc000-f9ffffff : 0000:04:00.0
    >
    > Some additional debug output tells me that the code is actually trying to allocate 16k starting from f9ffc000. What could be
    > potential reasons for the failure? Do I have to do something with the bridge before I can try to request the region?

    request_region is requesting IO ports. The PCI BAR on the card is MMIO
    memory, not IO ports, so request_mem_region has to be used. It's
    possible that this driver isn't set up to handle MMIO space.


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