Re: [PATCH 2/4] PCI: designware: get rid of pci_scan_root_bus

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On Wed, Jul 23, 2014 at 11:22 PM, Lucas Stach <l.stach@xxxxxxxxxxxxxx> wrote:
> Use pci_create_root_bus() similar to other pci
> host controller drivers.
>
> The main problem with pci_scan_root_bus() is that
> not only it will create the root bus, but also try
> to activate all devices on the bus. This triggers
> PCI device drivers probe, which try to use the device
> but fail as resource allocation isn't done at that
> point in time.
>
> To work around this we made sure that the host
> controller driver is probed early and finishes resource
> allocation before any other device drivers are registered.
> Switching to pci_create_root_bus() allows us to get rid
> of this special handling.
>
> Signed-off-by: Lucas Stach <l.stach@xxxxxxxxxxxxxx>
> ---
>  drivers/pci/host/pcie-designware.c | 15 +++++++--------
>  1 file changed, 7 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/pci/host/pcie-designware.c b/drivers/pci/host/pcie-designware.c
> index b13a830c8b0f..b869e202367c 100644
> --- a/drivers/pci/host/pcie-designware.c
> +++ b/drivers/pci/host/pcie-designware.c
> @@ -801,14 +801,13 @@ static struct pci_bus *dw_pcie_scan_bus(int nr, struct pci_sys_data *sys)
>         struct pci_bus *bus;
>         struct pcie_port *pp = sys_to_pcie(sys);
>
> -       if (pp) {
> -               pp->root_bus_nr = sys->busnr;
> -               bus = pci_scan_root_bus(pp->dev, sys->busnr, &dw_pcie_ops,
> -                                       sys, &sys->resources);
> -       } else {
> -               bus = NULL;
> -               BUG();
> -       }
> +       pp->root_bus_nr = sys->busnr;
> +       bus = pci_create_root_bus(pp->dev, sys->busnr,
> +                                 &dw_pcie_ops, sys, &sys->resources);
> +       if (!bus)
> +               return NULL;
> +
> +       pci_scan_child_bus(bus);
>
>         return bus;
>  }
> --

Looks fine to me.
Reviewed-by: Pratyush Anand <pratyush.anand@xxxxxx>

> 2.0.1
>
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