linux-kernel - Re: [PATCH 2/2] ACPI / video / i915: Remove ACPI backlight if firmware expects Windows 8

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Date:	Tue, 10 Sep 2013 14:21:26 +0000
From:	Matthew Garrett <matthew.garrett@...ula.com>
To:	Jani Nikula <jani.nikula@...ux.intel.com>
CC:	"Rafael J. Wysocki" <rjw@...k.pl>, Daniel Vetter <daniel@...ll.ch>,
	"Aaron Lu" <aaron.lu@...el.com>,
	ACPI Devel Mailing List <linux-acpi@...r.kernel.org>,
	Daniel Vetter <daniel.vetter@...ll.ch>,
	"intel-gfx@...ts.freedesktop.org" <intel-gfx@...ts.freedesktop.org>,
	Yves-Alexis Perez <corsac@...ian.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"dri-devel@...ts.freedesktop.org" <dri-devel@...ts.freedesktop.org>,
	Seth Forshee <seth.forshee@...onical.com>,
	"Lee, Chun-Yi" <joeyli.kernel@...il.com>,
	Igor Gnatenko <i.gnatenko.brain@...il.com>,
	Henrique de Moraes Holschuh <hmh@....eng.br>,
	Lee Chun-Yi <jlee@...ell.com>, Len Brown <lenb@...nel.org>
Subject: Re: [PATCH 2/2] ACPI / video / i915: Remove ACPI backlight if
 firmware expects Windows 8

On Tue, 2013-09-10 at 17:21 +0300, Jani Nikula wrote:
> On Tue, 10 Sep 2013, Matthew Garrett <matthew.garrett@...ula.com> wrote:
> > On Tue, 2013-09-10 at 16:53 +0300, Jani Nikula wrote:
> >
> >> I think the parameter "Does the ACPI backlight interface work or not"
> >> belongs to the ACPI video driver.
> >
> > That depends on how Windows 8 works. If Windows 8 policy is handled by
> > the GPU drivers then it belongs in i915. If it's handled by the ACPI
> > code then it belongs in the ACPI code.
> 
> I fail to see the logic. Windows 8 policy dictates whether we can use
> the AML code or not. IMHO, ACPI code is in the best position to figure
> this out and quirk as necessary. It's the part that knows about Windows
> 8, not i915.

So if nvidia hardware uses the ACPI interface and Intel doesn't, we
should still quirk it in the ACPI driver?

-- 
Matthew Garrett <matthew.garrett@...ula.com>