Re: [PATCH v1 2/3] PCI / ACPI: Remove the need for 'struct hotplug_params'

Bjorn Helgaas
2019-04-19T22:02:20Z

On Fri, Apr 19, 2019 at 03:07:45PM -0500, Bjorn Helgaas wrote:
> On Fri, Feb 08, 2019 at 10:24:12AM -0600, Alexandru Gagniuc wrote:
> > We used to first parse all the _HPP and _HPX tables before using the
> > information to program registers of PCIe devices. Up until HPX type 2,
> > there was only one structure of each type, so we could cheat and store
> > it on the stack.
> >
> > With HPX type 3 we get an arbitrary number of entries, so the above
> > model doesn't scale that well. Instead of parsing all tables at once,
> > parse and program each entry separately. For _HPP and _HPX 0 thru 2,
> > this is functionally equivalent. The change enables the upcoming _HPX3
> > to integrate more easily.
>
> I think this is tremendous! It's going to simplify this code
> dramatically. Two comments below.

> > static void pci_configure_device(struct pci_dev *dev)
> > {
> > - struct hotplug_params hpp;
> > - int ret;
> > + static const struct hotplug_program_ops hp_ops = {
> > + .program_type0 = program_hpp_type0,
> > + .program_type1 = program_hpp_type1,
> > + .program_type2 = program_hpp_type2,
> > + };
>
> What if we just moved program_hpp_type0(), etc from probe.c to
> pci-acpi.c? The only reason I see to have it in probe.c is for
> pci_default_type0, and I think that is a pretty obtuse way of doing
> default configuration. I would have no problem at all just hardcoding
> those defaults in probe.c and then potentially having them overwritten
> by _HPP/_HPX.

Actually, never mind about this. This would be a perfect project for
mentoring a Linux newbie.

I'll merge this series as-is and any restructuring/cleanup can happen
later, since it's not related to this series anyway.

Bjorn