From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-acpi-owner@vger.kernel.org>
Message-ID: <0af2f9224de068c2ffe4f4d64c8285cd7dab9e91.camel@linux.intel.com>
Subject: Re: [PATCH v7 11/12] PCI: Improve "partially hidden behind bridge"
 log message
From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: Mika Westerberg <mika.westerberg@linux.intel.com>,
        Bjorn Helgaas <bhelgaas@google.com>,
        "Rafael J . Wysocki" <rjw@rjwysocki.net>
Cc: Len Brown <lenb@kernel.org>, Mario.Limonciello@dell.com,
        Michael Jamet <michael.jamet@intel.com>,
        Yehezkel Bernat <YehezkelShB@gmail.com>,
        Lukas Wunner <lukas@wunner.de>, linux-pci@vger.kernel.org,
        linux-acpi@vger.kernel.org
Date: Thu, 17 May 2018 14:44:19 +0300
In-Reply-To: <20180517092903.43701-12-mika.westerberg@linux.intel.com>
References: <20180517092903.43701-1-mika.westerberg@linux.intel.com>
         <20180517092903.43701-12-mika.westerberg@linux.intel.com>
Content-Type: text/plain; charset="UTF-8"
Mime-Version: 1.0
Sender: linux-acpi-owner@vger.kernel.org
List-ID: <linux-pci.vger.kernel.org>

On Thu, 2018-05-17 at 12:29 +0300, Mika Westerberg wrote:
> There is a sanity checker in the end of pci_scan_child_bus_extend()
> that
> tries to detect badly configured bridges. For example given the below
> topology:
> 
>   +-1b.0-[01-39]----00.0-[02-3a]--+-00.0-[03]----00.0
>                                   +-01.0-[04-39]--
>                                   \-02.0-[3a]----00.0
> 
> The sanity checker notices this and logs following messages:
> 
>   pci_bus 0000:3a: [bus 3a] partially hidden behind bridge 0000:02
> [bus 02-39]
>   pci_bus 0000:3a: [bus 3a] partially hidden behind bridge 0000:01
> [bus 01-39]
> 
> This is not really helpful to users and the information above is not
> even correct (0000:02 is a bus not bridge). Make this a bit more
> understandable by changing the sanity checker to log following message
> in place of the above two messages:
> 
>   pci 0000:02:02.0: devices behind bridge are unusable, because [bus
> 3a] cannot be assigned for them
> 
> While there update the comment on top of the sanity checker block to
> make it clear that it is not only restricted to CardBus.
> 

Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

> Suggested-by: Bjorn Helgaas <bhelgaas@google.com>
> Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
> Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> ---
>  drivers/pci/probe.c | 14 +++++---------
>  1 file changed, 5 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
> index a0c48aa1c42f..10084990fbc3 100644
> --- a/drivers/pci/probe.c
> +++ b/drivers/pci/probe.c
> @@ -1191,20 +1191,16 @@ static int pci_scan_bridge_extend(struct
> pci_bus *bus, struct pci_dev *dev,
>  		(is_cardbus ? "PCI CardBus %04x:%02x" : "PCI Bus
> %04x:%02x"),
>  		pci_domain_nr(bus), child->number);
>  
> -	/* Has only triggered on CardBus, fixup is in yenta_socket */
> +	/* Check that all devices are accessible */
>  	while (bus->parent) {
>  		if ((child->busn_res.end > bus->busn_res.end) ||
>  		    (child->number > bus->busn_res.end) ||
>  		    (child->number < bus->number) ||
>  		    (child->busn_res.end < bus->number)) {
> -			dev_info(&child->dev, "%pR %s hidden behind%s
> bridge %s %pR\n",
> -				&child->busn_res,
> -				(bus->number > child->busn_res.end &&
> -				 bus->busn_res.end < child->number) ?
> -					"wholly" : "partially",
> -				bus->self->transparent ? "
> transparent" : "",
> -				dev_name(&bus->dev),
> -				&bus->busn_res);
> +			dev_info(&dev->dev,
> +				 "devices behind bridge are unusable,
> because %pR cannot be assigned for them\n",
> +				 &child->busn_res);
> +			break;
>  		}
>  		bus = bus->parent;
>  	}

-- 
Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Intel Finland Oy