[PATCH 01/13] PCI: dwc/imx6: Drop setting PCI_MSI_FLAGS_ENABLE

[Rob Herring]

On Wed, Oct 28, 2020 at 7:21 PM Michael Ellerman <mpe at ellerman.id.au> wrote:
>
> Rob Herring <robh at kernel.org> writes:
> > No other host driver sets the PCI_MSI_FLAGS_ENABLE bit, so it must not
> > be necessary. If it is, a comment is needed.
>
> Yeah, but git blame directly points to:
>
>   75cb8d20c112 ("PCI: imx: Enable MSI from downstream components")

I think I did read this at some point and then forgot about it when I
made the change later...

> Which has a pretty long explanation. The relevant bit probably being:
>
>   ... on i.MX6, the MSI Enable bit controls delivery of MSI interrupts
>   from components below the Root Port.

The thing is that all seems not i.MX6 specific but DWC specific given
MSI handling is contained within the DWC block. So I don't see how
this could be an integration difference.

So maybe everyone else is still just setting CONFIG_PCIEPORTBUS
typically and haven't noticed? Is it correct for the host driver to
set MSI enable?

Rob