[RFC] drm/kms: control display brightness through drm_connector properties

Ville Syrjälä ville.syrjala at linux.intel.com
Wed May 18 14:40:58 UTC 2022

On Wed, May 18, 2022 at 02:59:58PM +0200, Hans de Goede wrote:
> Hi,
> On 4/14/22 15:10, Jani Nikula wrote:
> > There are some cases where we can actually get a rough PWM/luminance
> > curve from i915 opregion. I think maybe 16 data points. We've never
> > exposed that. My idea was that you'd have a property where you could add
> > data points for the curve, it could get pre-populated by the kernel if
> > the kernel knows how to do it, defaulting to linear, but it could also
> > be set or adjusted by userspace. The point would be that the userspace
> > adjusts brightness linearly, and the kernel would use the curve data
> > points to adjust it non-linearly. The userspace could have completely
> > separated brightness adjustment and curve adjustment, and the brightness
> > adjustment would be dead simple.
> Interesting, I guess this could be a future feature addition on top
> of my work.

Here's an outdated branch:

Wrote that some years ago after getting fed up with the useless
non-linear respose of the brightness up/down buttons on my laptop.
Been running it ever since.

Ville Syrjälä

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