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Date: Mon, 22 Nov 2010 12:30:50 +0000
From: Matthew Garrett <mjg59@srcf.ucam.org>
To: Richard Purdie <rpurdie@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>, linux-kernel@vger.kernel.org,
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Subject: Re: [PATCH 1/5] Backlight: Add backlight type
Message-ID: <20101122123050.GA5385@srcf.ucam.org>
References: <1290182036-30484-1-git-send-email-mjg@redhat.com> <20101119120523.15bc341c.akpm@linux-foundation.org> <20101119202558.GA10898@srcf.ucam.org> <1290421020.1272.16707.camel@rex>
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On Mon, Nov 22, 2010 at 10:17:00AM +0000, Richard Purdie wrote:

> I also want to make sure you think this patch is going to scale with
> multiple GPU output machines? Thats the main reason I've held off any
> patch like this as it doesn't help solve that problem as far as I can
> tell. Yes, we have the device parent information and I see later in the
> patch series you ensure the backlight is registered against the
> connector which is good. If you have an ACPI "firmware" control that you
> say should always be preferred, how do we know which connector device
> that corresponds to in the multiple output case? From that point of view
> this model falls apart?

The ACPI device will point at the correct PCI device. Associating it 
with the appropriate connector is theoretically possible in the case of 
open drivers, but I hadn't seen it as a high priority since (in 
practice) there's no situations where an ACPI interface will be able to 
control more than one backlight.

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