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From: Arnd Bergmann <arnd@arndb.de>
To: linux-arm-kernel@lists.infradead.org
Subject: Re: [RFC PATCH 01/16] PCI: Enhance pci_scan_root_bus() to support
 default IO/MEM resources
Date: Mon, 17 Nov 2014 11:08:34 +0100
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Cc: Liviu Dudau <liviu@dudau.co.uk>, Tony Luck <tony.luck@intel.com>,
 Russell King <linux@arm.linux.org.uk>, linux-pci@vger.kernel.org,
 x86@kernel.org, linux-kernel@vger.kernel.org, Xinwei Hu <huxinwei@huawei.com>,
 Bjorn Helgaas <bhelgaas@google.com>, Thierry Reding <thierry.reding@gmail.com>,
 Suravee.Suthikulpanit@amd.com, Yijing Wang <wangyijing@huawei.com>,
 linux-ia64@vger.kernel.org, Thomas Gleixner <tglx@linutronix.de>,
 Wuyun <wuyun.wu@huawei.com>, linuxppc-dev@lists.ozlabs.org,
 Yijing Wang <wangyijing0307@gmail.com>
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On Monday 17 November 2014 18:21:35 Yijing Wang wrote:
> -       list_for_each_entry(window, resources, list)
> -               if (window->res->flags & IORESOURCE_BUS) {
> -                       found = true;
> -                       break;
> -               }
> +       if (!resources) {
> +               pci_add_resource(&default_res, &ioport_resource);
> +               pci_add_resource(&default_res, &iomem_resource);
> +               pci_add_resource(&default_res, &busn_resource);
> +       } else {
> 

Isn't it almost always wrong to do this? You are adding all of the
I/O ports and memory to the host bridge, which will prevent you from
adding another host bridge, and the iomem_resource normally
includes a lot of addresses that are not accessible by the PCI host.

	Arnd