Re: [PATCH 00/36] AArch64 Linux kernel port

From: Matthew Garrett
Date: Mon Jul 09 2012 - 10:02:18 EST


On Mon, Jul 09, 2012 at 02:56:26PM +0100, Mark Brown wrote:
> On Mon, Jul 09, 2012 at 02:06:29PM +0100, Matthew Garrett wrote:
>
> > There's ongoing discussion about unifying ACPI and ftd representation,
> > and once that's done this isn't a problem, but right now there's no
>
> Where is this discussion?

My part of it has pretty much been in-person discussion with Grant
Likely, but there was some on ksummit-discuss last month.

> > terribly straightforward way to do this without a lot of basically
> > boilerplate code. The biggest issue is that ACPI has a very different
> > idea about event delivery and we'd need some way to abstract that.
>
> Right, but there's lots of bolierplate code with this stuff anyway and
> it's not fundamentally hard. Last time I looked at ACPI it had a rather
> different model for how all this stuff would work than DT did which
> isn't terribly helpful here.

ACPI 5 lets devices expose their GPIO resources directly, so in some
cases a driver will just be able to request that and handle things as it
would in ftd. But the more traditional ACPI method is to use ACPI
notifications, and those happen in process context. It seems unlikely
that everyone's going to get it right unless there's existing in-kernel
infrastructure for handling this.

--
Matthew Garrett | mjg59@xxxxxxxxxxxxx
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