linux-kernel - Re: [PATCH v2 3/3] ACPI / video: Do not register backlight if win8 and native interface exists

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <1379423079.2218.2.camel@ThinkPad-X230.localdomain>
Date:	Tue, 17 Sep 2013 17:04:39 +0400
From:	Igor Gnatenko <i.gnatenko.brain@...il.com>
To:	Aaron Lu <aaron.lu@...el.com>
Cc:	linux-acpi@...r.kernel.org, intel-gfx@...ts.freedesktop.org,
	dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
	Daniel Vetter <daniel@...ll.ch>,
	"Rafael J. Wysocki" <rjw@...k.pl>,
	Matthew Garrett <matthew.garrett@...ula.com>,
	Seth Forshee <seth.forshee@...onical.com>,
	Lee Chun-Yi <joeyli.kernel@...il.com>,
	Richard Purdie <rpurdie@...ys.net>,
	Yves-Alexis Perez <corsac@...ian.org>,
	Felipe Contreras <felipe.contreras@...il.com>,
	Henrique de Moraes Holschuh <ibm-acpi@....eng.br>,
	Jani Nikula <jani.nikula@...ux.intel.com>
Subject: Re: [PATCH v2 3/3] ACPI / video: Do not register backlight if win8
 and native interface exists

On Tue, 2013-09-17 at 17:23 +0800, Aaron Lu wrote:
> According to Matthew Garrett, "Windows 8 leaves backlight control up
> to individual graphics drivers rather than making ACPI calls itself.
> There's plenty of evidence to suggest that the Intel driver for
> Windows 8 doesn't use the ACPI interface, including the fact that
> it's broken on a bunch of machines when the OS claims to support
> Windows 8.  The simplest thing to do appears to be to disable the
> ACPI backlight interface on these systems".
> 
> So for Win8 systems, if there is native backlight control interface
> registered by GPU driver, ACPI video will not register its own. For
> users who prefer to keep ACPI video's backlight interface, the existing
> kernel cmdline option acpi_backlight=video can be used.
> 
> This patch is an evolution from previous work done by Matthew Garrett,
> Chun-Yi Lee, Seth Forshee and Rafael J. Wysocki.
> 
> Signed-off-by: Aaron Lu <aaron.lu@...el.com>
Tested-by: Igor Gnatenko <i.gnatenko.brain@...il.com>
> ---
>  drivers/acpi/internal.h     |  5 ++---
>  drivers/acpi/video.c        | 27 +++++----------------------
>  drivers/acpi/video_detect.c | 14 ++++++++++++--
>  3 files changed, 19 insertions(+), 27 deletions(-)

-- 
Igor Gnatenko
Fedora release 20 (Heisenbug)
Linux 3.12.0-0.rc1.git0.1.fc20.x86_64

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/