Re: [PATCH 7/8] PCI: check if MSI is enabled before adding _OSC support capability

[Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>]

Andrew Patterson wrote:
> PCI: check if MSI is enabled before adding _OSC support capability
> 
> Ensure that pci=nomsi is not set before adding the _OSC support capability
> OSC_MSI_SUPPORT to the root bridge.
> 
> Signed-off-by: Andrew Patterson <andrew.patterson@hp.com>
> ---
> 
>  drivers/acpi/pci_root.c |   20 +++++++++++---------
>  1 files changed, 11 insertions(+), 9 deletions(-)
> 
> 
> diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
> index 75a59ea..32afd02 100644
> --- a/drivers/acpi/pci_root.c
> +++ b/drivers/acpi/pci_root.c
> @@ -194,6 +194,7 @@ static int __devinit acpi_pci_root_add(struct acpi_device *device)
>  	unsigned long long value = 0;
>  	acpi_handle handle = NULL;
>  	struct acpi_device *child;
> +	u32 flags;
>  
>  
>  	if (!device)
> @@ -211,17 +212,18 @@ static int __devinit acpi_pci_root_add(struct acpi_device *device)
>  
>  	device->ops.bind = acpi_pci_bind;
>  
> -	pci_acpi_osc_support(device->handle,
> -			     OSC_EXT_PCI_CONFIG_SUPPORT |
> -			     OSC_PCI_SEGMENT_GROUPS_SUPPORT |
> -#ifdef CONFIG_PCI_MSI
> -			     OSC_MSI_SUPPORT |
> -#endif
> +	flags = (OSC_EXT_PCI_CONFIG_SUPPORT |
> +		 OSC_PCI_SEGMENT_GROUPS_SUPPORT |
>  #ifdef CONFIG_PCIEASPM
> -			     OSC_ACTIVE_STATE_PWR_SUPPORT |
> -			     OSC_CLOCK_PWR_CAPABILITY_SUPPORT |
> +		 OSC_ACTIVE_STATE_PWR_SUPPORT |
> +		 OSC_CLOCK_PWR_CAPABILITY_SUPPORT |
> +#endif
> +		 0);
> +#ifdef CONFIG_PCI_MSI
> +	if (pci_msi_enabled())
> +		flags |= OSC_MSI_SUPPORT;
>  #endif
> -			     0);
> +	pci_acpi_osc_support(device->handle, flags);
>  
>  	/* 
>  	 * Segment

I think the 'pci_msi_enable' variable can be changed after
acpi_pci_root_add() is called by quirk_disable_all_msi()
(in driver/pci/quirk.c).

Thanks,
Kenji Kaneshige