On Wed, Feb 27, 2019 at 05:52:19PM +0100, Lucas Stach wrote:
> Since 7c5925afbc58 (PCI: dwc: Move MSI IRQs allocation to IRQ domains
> hierarchical API) the MSI init claims one of the controller IRQs as a
> chained IRQ line for the MSI controller. On some designs, like the i.MX6,
> this line is shared with a PCIe legacy IRQ. When the line is claimed for
> the MSI domain, any device trying to use this legacy IRQs will fail to
> request this IRQ line.
>
> As MSI and legacy IRQs are already mutually exclusive on the DWC core,
> as the core won't forward any legacy IRQs once any MSI has been enabled,
> users wishing to use legacy IRQs already need to explictly disable MSI
> support (usually via the pci=nomsi kernel commandline option). To avoid
> any issues with MSI conflicting with legacy IRQs, just skip all of the
> DWC MSI initalization, including the IRQ line claim, when MSI is disabled.
>
> Fixes: c5925afbc58
> (PCI: dwc: Move MSI IRQs allocation to IRQ domains hierarchical API)
> Signed-off-by: Lucas Stach <l.stach@xxxxxxxxxxxxxx>
> Tested-by: Tim Harvey <tharvey@xxxxxxxxxxxxx>
> ---
> drivers/pci/controller/dwc/pcie-designware-host.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
I request Gustavo's ACK to proceed, thanks.
Lorenzo
> diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c
> index 29a05759a294..f4a8494f616b 100644
> --- a/drivers/pci/controller/dwc/pcie-designware-host.c
> +++ b/drivers/pci/controller/dwc/pcie-designware-host.c
> @@ -433,7 +433,7 @@ int dw_pcie_host_init(struct pcie_port *pp)
> if (ret)
> pci->num_viewport = 2;
>
> - if (IS_ENABLED(CONFIG_PCI_MSI)) {
> + if (IS_ENABLED(CONFIG_PCI_MSI) && pci_msi_enabled()) {
> /*
> * If a specific SoC driver needs to change the
> * default number of vectors, it needs to implement
> --
> 2.20.1
>
