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From: Aaron Lu <aaron.lu@intel.com>
To: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: linux-acpi@vger.kernel.org, intel-gfx@lists.freedesktop.org,
	dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org,
	"Daniel Vetter" <daniel@ffwll.ch>,
	"Matthew Garrett" <matthew.garrett@nebula.com>,
	"Seth Forshee" <seth.forshee@canonical.com>,
	"Lee Chun-Yi" <joeyli.kernel@gmail.com>,
	"Richard Purdie" <rpurdie@rpsys.net>,
	"Igor Gnatenko" <i.gnatenko.brain@gmail.com>,
	"Yves-Alexis Perez" <corsac@debian.org>,
	"Felipe Contreras" <felipe.contreras@gmail.com>,
	"Henrique de Moraes Holschuh" <ibm-acpi@hmh.eng.br>,
	"Jani Nikula" <jani.nikula@linux.intel.com>,
	"Ben Jencks" <ben@bjencks.net>,
	"Steven Newbury" <steve@snewbury.org.uk>,
	"James Hogan" <james@albanarts.com>,
	"Kamal Mostafa" <kamal@canonical.com>,
	"Joerg Platte" <jplatte@naasa.net>,
	"Kalle Valo" <kvalo@adurom.com>,
	"Martin Steigerwald" <Martin@lichtvoll.de>,
	"Jörg Otte" <jrg.otte@gmail.com>,
	"Mike Galbraith" <bitbucket@onlin>
Subject: Re: [PATCH v3 3/4] ACPI / video: Do not register backlight if win8 and native interface exists
Date: Thu, 26 Sep 2013 13:15:53 +0800	[thread overview]
Message-ID: <20130926051552.GB14158@aaronlu.linux.com> (raw)
In-Reply-To: <2597446.Ay4U1OH2zV@vostro.rjw.lan>

On Wed, Sep 25, 2013 at 07:53:13PM +0200, Rafael J. Wysocki wrote:
> On Tuesday, September 24, 2013 05:47:31 PM 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.
> 
> I think the idea is to use the aggressive default for now and we can switch the
> default back to the current behavior before the merge window in case there are
> too many problems with it?

Yes I think so.

Thanks,
Aaron

WARNING: multiple messages have this Message-ID (diff)
From: Aaron Lu <aaron.lu@intel.com>
To: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: linux-acpi@vger.kernel.org, intel-gfx@lists.freedesktop.org,
	dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org,
	"Daniel Vetter" <daniel@ffwll.ch>,
	"Matthew Garrett" <matthew.garrett@nebula.com>,
	"Seth Forshee" <seth.forshee@canonical.com>,
	"Lee Chun-Yi" <joeyli.kernel@gmail.com>,
	"Richard Purdie" <rpurdie@rpsys.net>,
	"Igor Gnatenko" <i.gnatenko.brain@gmail.com>,
	"Yves-Alexis Perez" <corsac@debian.org>,
	"Felipe Contreras" <felipe.contreras@gmail.com>,
	"Henrique de Moraes Holschuh" <ibm-acpi@hmh.eng.br>,
	"Jani Nikula" <jani.nikula@linux.intel.com>,
	"Ben Jencks" <ben@bjencks.net>,
	"Steven Newbury" <steve@snewbury.org.uk>,
	"James Hogan" <james@albanarts.com>,
	"Kamal Mostafa" <kamal@canonical.com>,
	"Joerg Platte" <jplatte@naasa.net>,
	"Kalle Valo" <kvalo@adurom.com>,
	"Martin Steigerwald" <Martin@lichtvoll.de>,
	"Jörg Otte" <jrg.otte@gmail.com>,
	"Mike Galbraith" <bitbucket@online.de>
Subject: Re: [PATCH v3 3/4] ACPI / video: Do not register backlight if win8 and native interface exists
Date: Thu, 26 Sep 2013 13:15:53 +0800	[thread overview]
Message-ID: <20130926051552.GB14158@aaronlu.linux.com> (raw)
In-Reply-To: <2597446.Ay4U1OH2zV@vostro.rjw.lan>

On Wed, Sep 25, 2013 at 07:53:13PM +0200, Rafael J. Wysocki wrote:
> On Tuesday, September 24, 2013 05:47:31 PM 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.
> 
> I think the idea is to use the aggressive default for now and we can switch the
> default back to the current behavior before the merge window in case there are
> too many problems with it?

Yes I think so.

Thanks,
Aaron

  reply	other threads:[~2013-09-26  5:15 UTC|newest]

Thread overview: 46+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-09-24  9:47 [PATCH v3 0/4] Fix Win8 backlight issue Aaron Lu
2013-09-24  9:47 ` [PATCH v3 1/4] backlight: introduce backlight_device_registered Aaron Lu
2013-09-24  9:47 ` [PATCH v3 2/4] ACPI / video: seperate backlight control and event interface Aaron Lu
2013-09-24  9:54   ` Aaron Lu
2013-09-24  9:54     ` Aaron Lu
2013-10-07 12:09     ` Rafael J. Wysocki
2013-10-07 12:09       ` Rafael J. Wysocki
2013-09-24  9:47 ` [PATCH v3 3/4] ACPI / video: Do not register backlight if win8 and native interface exists Aaron Lu
2013-09-25 17:53   ` Rafael J. Wysocki
2013-09-25 17:53     ` Rafael J. Wysocki
2013-09-26  5:15     ` Aaron Lu [this message]
2013-09-26  5:15       ` Aaron Lu
2013-09-24  9:47 ` [PATCH v3 4/4] thinkpad-acpi: fix handle locate for video and query of _BCL Aaron Lu
2013-09-25 19:58   ` Henrique de Moraes Holschuh
2013-09-25 19:58     ` Henrique de Moraes Holschuh
2013-09-26  1:44     ` Aaron Lu
2013-09-26  1:44       ` Aaron Lu
2013-09-27 15:16       ` Henrique de Moraes Holschuh
2013-09-27 15:16         ` Henrique de Moraes Holschuh
2013-09-27 15:20   ` Henrique de Moraes Holschuh
2013-09-27 15:20     ` Henrique de Moraes Holschuh
2013-09-27 15:33     ` Yves-Alexis Perez
2013-09-27 15:33       ` Yves-Alexis Perez
2013-09-27 18:05       ` Henrique de Moraes Holschuh
2013-09-27 18:05         ` Henrique de Moraes Holschuh
2013-09-28 12:28         ` Yves-Alexis Perez
2013-09-28 12:28           ` Yves-Alexis Perez
2013-09-24 12:42 ` [PATCH v3 0/4] Fix Win8 backlight issue Igor Gnatenko
2013-09-25  8:29   ` Jörg Otte
2013-09-25  9:17     ` Aaron Lu
2013-09-25  9:17       ` Aaron Lu
2013-09-25 10:41       ` Jani Nikula
2013-09-25 10:41         ` Jani Nikula
2013-09-25 15:51         ` Jörg Otte
2013-09-25 15:51           ` Jörg Otte
2013-09-25 16:17           ` Jani Nikula
2013-09-25 16:17             ` Jani Nikula
2013-09-26  7:49             ` Jörg Otte
2013-09-26  7:49               ` Jörg Otte
2013-09-27  0:26               ` Rafael J. Wysocki
2013-09-27  0:26                 ` Rafael J. Wysocki
2013-09-28 16:34                 ` Jörg Otte
2013-09-28 16:34                   ` Jörg Otte
2013-09-25  9:09 ` Jörg Otte
2013-09-27 11:02 ` Mika Westerberg
2013-09-27 11:02   ` Mika Westerberg

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