From: Ben Skeggs <skeggsb-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
To: Aaron Sowry <aaron+nv-+1tCnOwpXBmzQB+pC5nmwQ@public.gmane.org>
Cc: nouveau-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org
Subject: Re: nouveau exposes backlight controls in presence of ACPI
Date: Wed, 03 Nov 2010 08:37:51 +1000 [thread overview]
Message-ID: <1288737471.6100.0.camel@nisroch> (raw)
In-Reply-To: <20101102145153.GA4075-+1tCnOwpXBmzQB+pC5nmwQ@public.gmane.org>
On Tue, 2010-11-02 at 15:51 +0100, Aaron Sowry wrote:
> > However. There's also the platform-specific modules (thinkpad etc) that
> > will provide their own backlight methods if the standard ACPI mechanism
> > isn't available. I didn't see any immediately obvious way of knowing
> > whether or not they were being provided.
> >
> > I'm not too certain the best way to deal with this, any ideas? :)
>
> See attached patch, which prevents nouveau registering a backlight control if ACPI already provides one. If there are no glaring errors in the code/implementation then I would like to submit it.
This is much like what I intended to commit. I guess it doesn't hurt to
do so, it doesn't help with all cases yet but if it fixes issues for
some people, why not.
Ben.
>
> Dealing with platform-specific modules is tricky because it looks like nouveau initialises itself quite early on in the boot process:
>
> [aaron@jules ~]$ dmesg | grep ACPI
> ...
> [ 3.359377] nouveau 0000:01:00.0: power state changed by ACPI to D0
> [ 3.359560] nouveau 0000:01:00.0: power state changed by ACPI to D0
> [ 4.860678] [drm] nouveau 0000:01:00.0: Detected ACPI backlight support, not registering control
> [ 14.206997] ACPI: WMI: Skipping duplicate GUID 05901221-D566-11D1-B2F0-00A0C9062910
> [ 14.207693] ACPI: WMI: Mapper loaded
> [ 17.686907] thinkpad_acpi: ThinkPad ACPI Extras v0.24
> [ 17.689517] thinkpad_acpi: This ThinkPad has standard ACPI backlight brightness control, supported by the ACPI video driver
> [ 17.756039] thinkpad_acpi: Standard ACPI backlight interface available, not loading native one.
>
> My suggestion would be that it is the responsibility of user-space to select an appropriate ACPI backlight control.
>
> /Aaron
next prev parent reply other threads:[~2010-11-02 22:37 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-10-29 15:49 nouveau exposes backlight controls in presence of ACPI Aaron Sowry
[not found] ` <20101029154934.GA2076-+1tCnOwpXBmzQB+pC5nmwQ@public.gmane.org>
2010-11-02 3:58 ` Ben Skeggs
2010-11-02 14:51 ` Aaron Sowry
[not found] ` <20101102145153.GA4075-+1tCnOwpXBmzQB+pC5nmwQ@public.gmane.org>
2010-11-02 22:37 ` Ben Skeggs [this message]
2010-11-02 16:37 ` Calvin Walton
2010-11-02 19:28 ` Aaron Sowry
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