Re: [patch 1/5] ACPI: move FADT resource reservations from motherboard driver to osl

[Bjorn Helgaas <bjorn.helgaas@hp.com>]

On Sunday 21 January 2007 18:27, Shaohua Li wrote:
> On Fri, 2007-01-19 at 12:46 -0700, Bjorn Helgaas wrote:
> > On Thursday 18 January 2007 18:12, Shaohua Li wrote:
> > > > +device_initcall(acpi_reserve_resources);
> > > Will this be called before PCI assigned resources to PCI devices? We use
> > > fs_initcall in motherboard to avoid PCI devices use motherboard's
> > > resources before.
> > 
> > I think we're OK.  Here's the current order:
> > 
> >   pnp_system_init            fs_initcall       drivers/pnp/system.c
> >   pcibios_assign_resources   fs_initcall       arch/i386/pci/i386.c
> >   acpi_reserve_resources     device_initcall   drivers/acpi/osl.c
> > 
> > So pnp_system_init() will reserve all the motherboard resources before
> > the PCI resources are assigned.  What do you think?
>
> In this way, we could just remove acpi_reserve_resources as pci already
> assigns resources to pci devices. The concern is motherboard might not
> list all acpi resources in its _CRS, but I don't know if there are such
> BIOS. Microsoft seems to reserve motherboard resources in the same way.
> Maybe we could just remove acpi_reserve_resources and give it a spin in
> -mm to see if anybody complains.

I agree that in theory we should be able to remove acpi_reserve_resources()
and just depend on pnp_system_init() reserving all the motherboard
resources.  But your concern is very valid: it looks like both HP DL360
(x86) and rx2600 (ia64) firmware list things in the FADT that aren't
included in _CRS for motherboard devices.  I think these are BIOS bugs,
but for now, it seems safest to keep acpi_reserve_resources() to work
around the bugs.

Bjorn