linux-kernel - Re: [PATCH v8 01/22] PCI, acpiphp: Add is_hotplug

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Date:	Tue, 15 Jan 2013 14:45:56 +0800
From:	Yijing Wang <wangyijing@...wei.com>
To:	Yinghai Lu <yinghai@...nel.org>
CC:	Bjorn Helgaas <bhelgaas@...gle.com>,
	"Rafael J. Wysocki" <rjw@...k.pl>, Len Brown <lenb@...nel.org>,
	Taku Izumi <izumi.taku@...fujitsu.com>,
	Jiang Liu <jiang.liu@...wei.com>, <linux-pci@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>, <linux-acpi@...r.kernel.org>
Subject: Re: [PATCH v8 01/22] PCI, acpiphp: Add is_hotplug_bridge detection

On 2013/1/12 6:40, Yinghai Lu wrote:
> When system support hotplug bridge with children hotplug slots, we need
> to make sure that parent bridge get preallocated resource so later when
> device is plugged into children slot, those children devices will get
> resource allocated.
> 
> We do not meet this problem, because for pcie hotplug card, when acpiphp
> is used, pci_scan_bridge will set that for us when detect hotplug bit in
> slot cap.
> 
> Reported-and-tested-by: Jason Baron <jbaron@...hat.com>
> Signed-off-by: Yinghai Lu <yinghai@...nel.org>
> Acked-by: Jason Baron <jbaron@...hat.com>
> ---
>  drivers/pci/hotplug/acpiphp_glue.c |   27 ++++++++++++++++++++++++++-
>  1 file changed, 26 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/pci/hotplug/acpiphp_glue.c b/drivers/pci/hotplug/acpiphp_glue.c
> index 91b5ad8..1e5c5df 100644
> --- a/drivers/pci/hotplug/acpiphp_glue.c
> +++ b/drivers/pci/hotplug/acpiphp_glue.c
> @@ -797,6 +797,29 @@ static void acpiphp_set_acpi_region(struct acpiphp_slot *slot)
>  	}
>  }
>  
> +static void check_hotplug_bridge(struct acpiphp_slot *slot, struct pci_dev *dev)
> +{
> +	struct acpiphp_func *func;
> +
> +	if (!dev->subordinate)
> +		return;
> +
> +	/* quirk, or pcie could set it already */
> +	if (dev->is_hotplug_bridge)
> +		return;
> +
> +	if (PCI_SLOT(dev->devfn) != slot->device)
> +		return;
> +
> +	list_for_each_entry(func, &slot->funcs, sibling) {
> +		if (PCI_FUNC(dev->devfn) == func->function) {
> +			/* check if this bridge has ejectable slots */
> +			if ((detect_ejectable_slots(func->handle) > 0))
> +				dev->is_hotplug_bridge = 1;
> +			break;

Hi Yinghai,
   Need to put the "break" in parentheses of "if"? If the first func which device number == dev->devfn has't ejectable slot,
don't check the rest funcs whether have ejectable slots?

> +		}
> +	}
> +}
>  /**
>   * enable_device - enable, configure a slot
>   * @slot: slot to be enabled
> @@ -831,8 +854,10 @@ static int __ref enable_device(struct acpiphp_slot *slot)
>  			if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE ||
>  			    dev->hdr_type == PCI_HEADER_TYPE_CARDBUS) {
>  				max = pci_scan_bridge(bus, dev, max, pass);
> -				if (pass && dev->subordinate)
> +				if (pass && dev->subordinate) {
> +					check_hotplug_bridge(slot, dev);
>  					pci_bus_size_bridges(dev->subordinate);
> +				}
>  			}
>  		}
>  	}
> 


-- 
Thanks!
Yijing

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