Re: [Linaro-acpi] [RFC part1 PATCH 1/7] ACPI: Make ACPI core running without PCI on ARM64

[Arnd Bergmann <arnd@arndb.de>]

On Tuesday 10 December 2013, Mark Brown wrote:
> On Tue, Dec 10, 2013 at 04:28:52AM +0100, Arnd Bergmann wrote:
> > On Monday 09 December 2013, Matthew Garrett wrote:
> 
> > > People are trying to deploy ACPI-based embedded x86, and most of the 
> > > ACPI/DT integration discussion seems to have been based on the idea that 
> > > this is a worthwhile thing to support. If we're not interested in doing 
> > > so then we should probably make that a whole kernel decision rather than 
> > > a per architecture one.
> 
> > Well, except it's not an architecture independent decision. An embedded
> > x86 SoC will still be very much like a PC, just with a few things added
> > in and some other bits left out, and you can already describe it mostly
> 
> It's not just the SoC, it's also the rest of the board.  The patches the
> Intel guys are submitting at the minute are mainly for the off-SoC
> devices at least as far as I noticed.  This'll impact anyone who ends up
> using ACPI, we need to at least pay attention to what's going on there.

Yes, but I'm not that worried about off-soc stuff, which tends to be
off the much simpler variety: a few MMIO or PIO registers, IRQs,
GPIOs or (with ACPI-5.0) devices on i2c and spi buses.

> > with plain ACPI-5.0. Also, there are only a couple of different non-PC style
> > devices that Intel is integrating into their SoCs, so we're talking
> > about a few dozen device drivers here.
> 
> It's going to be way more than that for the whole system, and you can't
> assume that all the system integrators are going to pay a blind bit of
> notice to the reference designs.  Some will just clone them but others
> will bin them and do their own thing.

They won't be able to change the on-chip components for obvious reasons.

	Arnd