Re: [PATCH 1/1] PCI: acpi_pcihp, run _OSC on a root bridge

[Jesse Barnes]

[Cc'ing Alex & Kenji-san for their comments on this fix.]

On Monday, August 11, 2008 8:47 am Jiri Slaby wrote:
> _OSC should be ran on a root bridge instead of the device itself.
> Do this before touching OSHP since PCI fw specs states that _OSC
> should be preferred over OSHP (however if the device has OSHP but
> not _OSC -- not a root bridge -- it's not).
>
> Signed-off-by: Jiri Slaby <jirislaby@xxxxxxxxx>
> Cc: kristen.c.accardi@xxxxxxxxx
> Cc: Jesse Barnes <jbarnes@xxxxxxxxxxxxxxxx>
> ---
>  drivers/pci/hotplug/acpi_pcihp.c |   41
> ++++++++++++++++++++++++++----------- 1 files changed, 29 insertions(+), 12
> deletions(-)
>
> diff --git a/drivers/pci/hotplug/acpi_pcihp.c
> b/drivers/pci/hotplug/acpi_pcihp.c index 93e37f0..bd83197 100644
> --- a/drivers/pci/hotplug/acpi_pcihp.c
> +++ b/drivers/pci/hotplug/acpi_pcihp.c
> @@ -382,7 +382,7 @@ EXPORT_SYMBOL_GPL(acpi_get_hp_params_from_firmware);
>  int acpi_get_hp_hw_control_from_firmware(struct pci_dev *dev, u32 flags)
>  {
>  	acpi_status status;
> -	acpi_handle chandle, handle = DEVICE_ACPI_HANDLE(&(dev->dev));
> +	acpi_handle chandle, handle;
>  	struct pci_dev *pdev = dev;
>  	struct pci_bus *parent;
>  	struct acpi_buffer string = { ACPI_ALLOCATE_BUFFER, NULL };
> @@ -399,10 +399,28 @@ int acpi_get_hp_hw_control_from_firmware(struct
> pci_dev *dev, u32 flags) * Per PCI firmware specification, we should run
> the ACPI _OSC
>  	 * method to get control of hotplug hardware before using it. If
>  	 * an _OSC is missing, we look for an OSHP to do the same thing.
> -	 * To handle different BIOS behavior, we look for _OSC and OSHP
> -	 * within the scope of the hotplug controller and its parents,
> +	 * To handle different BIOS behavior, we look for _OSC on a root
> +	 * bridge preferentially (according to PCI fw spec). Later for
> +	 * OSHP within the scope of the hotplug controller and its parents,
>  	 * upto the host bridge under which this controller exists.
>  	 */
> +	while (pdev->bus->self)
> +		pdev = pdev->bus->self;
> +	handle = acpi_get_pci_rootbridge_handle(pci_domain_nr(pdev->bus),
> +			pdev->bus->number);
> +	if (handle) {
> +		acpi_get_name(handle, ACPI_FULL_PATHNAME, &string);
> +		dbg("Trying to get hotplug control for %s\n",
> +				(char *)string.pointer);
> +		status = pci_osc_control_set(handle, flags);
> +		if (ACPI_SUCCESS(status))
> +			goto got_one;
> +		kfree(string.pointer);
> +		string = (struct acpi_buffer){ ACPI_ALLOCATE_BUFFER, NULL };
> +	}
> +
> +	pdev = dev;
> +	handle = DEVICE_ACPI_HANDLE(&dev->dev);
>  	while (!handle) {
>  		/*
>  		 * This hotplug controller was not listed in the ACPI name
> @@ -427,15 +445,9 @@ int acpi_get_hp_hw_control_from_firmware(struct
> pci_dev *dev, u32 flags) acpi_get_name(handle, ACPI_FULL_PATHNAME,
> &string);
>  		dbg("Trying to get hotplug control for %s \n",
>  		    (char *)string.pointer);
> -		status = pci_osc_control_set(handle, flags);
> -		if (status == AE_NOT_FOUND)
> -			status = acpi_run_oshp(handle);
> -		if (ACPI_SUCCESS(status)) {
> -			dbg("Gained control for hotplug HW for pci %s (%s)\n",
> -			    pci_name(dev), (char *)string.pointer);
> -			kfree(string.pointer);
> -			return 0;
> -		}
> +		status = acpi_run_oshp(handle);
> +		if (ACPI_SUCCESS(status))
> +			goto got_one;
>  		if (acpi_root_bridge(handle))
>  			break;
>  		chandle = handle;
> @@ -449,6 +461,11 @@ int acpi_get_hp_hw_control_from_firmware(struct
> pci_dev *dev, u32 flags)
>
>  	kfree(string.pointer);
>  	return -ENODEV;
> +got_one:
> +	dbg("Gained control for hotplug HW for pci %s (%s)\n", pci_name(dev),
> +			(char *)string.pointer);
> +	kfree(string.pointer);
> +	return 0;
>  }
>  EXPORT_SYMBOL(acpi_get_hp_hw_control_from_firmware);



-- 
Jesse Barnes, Intel Open Source Technology Center
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