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Date: Wed, 31 Jul 2013 15:00:10 +0100
From: Matthew Garrett <mjg59@srcf.ucam.org>
To: Felipe Contreras <felipe.contreras@gmail.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>, Aaron Lu <aaron.lwe@gmail.com>,
        linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org,
        Len Brown <lenb@kernel.org>,
        Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [REGRESSION/PATCH] acpi: blacklist win8 OSI for ASUS Zenbok
 Prime UX31A
Message-ID: <20130731140010.GA24560@srcf.ucam.org>
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On Wed, Jul 31, 2013 at 06:32:47AM -0500, Felipe Contreras wrote:
> On Wed, Jul 31, 2013 at 12:14 AM, Matthew Garrett <mjg59@srcf.ucam.org> wrote:
> > There's no mechanism for an OS to know whether or not a firmware
> > implementation will actually turn the backlight off at 0, so there's no
> > way the OS can define the lowest backlight state as anything other than
> > "May or may not turn the screen off".
> 
> Yes there is; quirks.

We aren't going to maintain a quirk list in order to support a guarantee 
that was never made. "0" as a backlight level has potentially meant 
"screen off" since the interface was first introduced.

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