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

Bjorn Helgaas
2008-10-29T14:33:23Z

On Tuesday 28 October 2008 11:48:51 pm 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);

I think this should be folded into patch 5/8. Otherwise, bisection
won't work across this series because at patch 5, we always add
OSC_MSI_SUPPORT, regardless of "pci=nomsi".

If you introduce "flags" in patch 2/8, the rest of the patches will
be clearer (and it will facilitate a useful dev_warn() when
pci_acpi_osc_support() fails).

You don't need the "#ifdef CONFIG_PCI_MSI" here, do you?

Bjorn