Laptop Panel brightness control

Matthew Garrett mjg59 at
Wed Jan 6 09:05:12 PST 2010

On Mon, Jan 04, 2010 at 01:37:00PM -0500, Adam Jackson wrote:
> On Mon, 2009-12-28 at 15:59 +0100, Sylvain Defresne wrote:
> > Hello,
> > 
> > In 2006 a property laptop_panel.brightness_in_hardware was added to
> > HAL [1] to inform client of different handling of the bightness
> > control key by the BIOS (some BIOSes forward the event to the
> > userspace, some handle them directly, some both handle them and
> > forward them to userspace).

The kernel now sends appropriate information to userspace to allow it to 
respond appropriately.

> The brightness control should be internally routed in the kernel to be a
> DRM output property, which the X server then proxies through as a RANDR
> output property.  DeviceKit doesn't get involved here, just make the
> kernel do the right thing.

I'd disagree with this. It ought to be exposed as a backlight class 
device, for consistency with everything else. The server may want to 
then expose it as a RANDR property.

Matthew Garrett | mjg59 at

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