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Date: Mon, 7 Feb 2011 21:34:26 +0000
From: Matthew Garrett <mjg59@srcf.ucam.org>
To: Bjorn Helgaas <bjorn.helgaas@hp.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>, dri-devel@lists.freedesktop.org,
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        linux-kernel@vger.kernel.org, rpurdie@rpsys.net,
        Len Brown <lenb@kernel.org>
Subject: Re: [PATCH 5/5] ACPI: Tie ACPI backlight devices to PCI devices if
	possible
Message-ID: <20110207213426.GA23843@srcf.ucam.org>
References: <1295033065-13450-1-git-send-email-mjg@redhat.com> <20110206230558.GA23889@srcf.ucam.org> <201102070034.43691.rjw@sisk.pl> <201102071432.35656.bjorn.helgaas@hp.com>
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On Mon, Feb 07, 2011 at 02:32:35PM -0700, Bjorn Helgaas wrote:

> I'm not familiar with video devices, but I agree, this situation does
> feel broken.  Is it the case that there's a PCI device as well as an
> ACPI namespace Device for the same piece of hardware?  If so, I assume
> the reason for the ACPI Device is to have a "standard" interface to
> a platform knob like backlight control.
> 
> In that case, it seems like we should rely on PCI for enumeration and
> driver binding, have some sort of hook the PCI driver could use to
> twiddle that knob (using the ACPI methods), and make the ACPI Device
> ineligible for driver binding.  In other words, it sounds like part
> of the problem is that we have two drivers binding to what's really
> a single piece of hardware.

Part of the problem is that ACPI video devices aren't inherently PCI 
devices.

-- 
Matthew Garrett | mjg59@srcf.ucam.org
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