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Subject: Re: [RFC PATCH] ACPI/PCI: Fix bus range comparation in
 pci_mcfg_lookup
To: "Rafael J. Wysocki" <rjw@rjwysocki.net>, Len Brown <lenb@kernel.org>,
        Tomasz Nowicki <tn@semihalf.com>,
        Jayachandran C <jchandra@broadcom.com>,
        Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
        jorn Helgaas <bhelgaas@google.com>
References: <1482397663-98715-1-git-send-email-wangzhou1@hisilicon.com>
CC: <liudongdong3@huawei.com>, <gabriele.paoloni@huawei.com>,
        <linux-acpi@vger.kernel.org>, <linux-pci@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>
From: Zhou Wang <wangzhou1@hisilicon.com>
Message-ID: <586AFE53.6000602@hisilicon.com>
Date: Tue, 3 Jan 2017 09:28:51 +0800
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On 2016/12/22 17:07, Zhou Wang wrote:
> Multiple PCIe host bridges may exists in one PCIe segment. So bus range for each
> host bridge should be in the coverage of bus range of related PCIe segment.
> 
> This patch will support this kind of scenario:
> 
> MCFG:
> 	bus range: 0x00~0xff.
> 	segment: 0.
> DSDT:
> 	host bridge 1:
> 		bus range: 0x00~0x1f.
> 		segment: 0.
> 	host bridge 2:
> 		bus range: 0x20~0x4f.
> 		segment: 0.
> 
> Signed-off-by: Zhou Wang <wangzhou1@hisilicon.com>
> ---
>  drivers/acpi/pci_mcfg.c | 5 ++---
>  1 file changed, 2 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/acpi/pci_mcfg.c b/drivers/acpi/pci_mcfg.c
> index b5b376e..46a3e32 100644
> --- a/drivers/acpi/pci_mcfg.c
> +++ b/drivers/acpi/pci_mcfg.c
> @@ -40,11 +40,10 @@ phys_addr_t pci_mcfg_lookup(u16 seg, struct resource *bus_res)
>  	struct mcfg_entry *e;
>  
>  	/*
> -	 * We expect exact match, unless MCFG entry end bus covers more than
> -	 * specified by caller.
> +	 * We expect the range in bus_res in the coverage of MCFG bus range.
>  	 */
>  	list_for_each_entry(e, &pci_mcfg_list, list) {
> -		if (e->segment == seg && e->bus_start == bus_res->start &&
> +		if (e->segment == seg && e->bus_start <= bus_res->start &&
>  		    e->bus_end >= bus_res->end)
>  			return e->addr;
>  	}
> 

Any idea about this RFC patch?

Thanks,
Zhou

.