On Thursday, May 10, 2018 8:28:36 PM CEST Mika Westerberg wrote:
> Currently pciehp_is_native() returns true for any PCI device in a
> hierarchy where _OSC says we can use pciehp. This is not correct because
> there may be bridges without PCI_EXP_SLTCAP_HPC capability and those
> should be managed by acpiphp instead.
>
> Improve pciehp_is_native() to return true only if the given bridge is
> actually expected to be handled by pciehp. In any other case return
> false instead to let acpiphp handle those.
>
> Suggested-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
> Signed-off-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
> ---
> drivers/pci/pci-acpi.c | 28 ++++++++++++++++------------
> drivers/pci/pcie/portdrv.h | 2 --
> include/linux/pci.h | 2 ++
> include/linux/pci_hotplug.h | 4 ++--
> 4 files changed, 20 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/pci/pci-acpi.c b/drivers/pci/pci-acpi.c
> index 1abdbf267c19..d3114f3a7ab8 100644
> --- a/drivers/pci/pci-acpi.c
> +++ b/drivers/pci/pci-acpi.c
> @@ -370,26 +370,30 @@ EXPORT_SYMBOL_GPL(pci_get_hp_params);
>
> /**
> * pciehp_is_native - Check whether a hotplug port is handled by the OS
> - * @pdev: Hotplug port to check
> + * @bridge: Hotplug port to check
> *
> - * Walk up from @pdev to the host bridge, obtain its cached _OSC Control Field
> - * and return the value of the "PCI Express Native Hot Plug control" bit.
> - * On failure to obtain the _OSC Control Field return %false.
> + * Returns true if the given @bridge is handled by the native PCIe hotplug
> + * driver.
> */
> -bool pciehp_is_native(struct pci_dev *pdev)
> +bool pciehp_is_native(struct pci_dev *bridge)
> {
> - struct acpi_pci_root *root;
> - acpi_handle handle;
> + const struct pci_host_bridge *host;
> + u32 slot_cap;
>
> - handle = acpi_find_root_bridge_handle(pdev);
> - if (!handle)
> + if (!pciehp_available())
> + return false;
> + if (!bridge)
> return false;
You could write this as
if (!pciehp_available() || !bridge)
return false;
Would be equivalent, but more concise IMO.
But anyway
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
