[i915] Backlight brighter since 3.9.0

[Joakim Plate]

Hi,

> 
> 2013/5/20 Daniel Vetter <daniel <at> ffwll.ch>
> Yeah, this is a feature. HDMI has (for oddball backwards compat with
> analog TV signals) a special mode which reduces the useable RGB value
> range by chopping off about 10% at the bottom and top end. This results in
> light colors getting brighter and dark colors getting darker.
> The above mentioned commit tries (to the best of our knowledge) to
> auto-set the option which most likely fits what the hdmi sink will do with
> the color data. You can either fix this up in the hdmi sink with the
> on-screen menu or by manually setting the "RBG Broadcast" property for the
> relevant hdmi connector to the setting you want.
> Cheers, Daniel--
> Daniel Vetter
> Software Engineer, Intel Corporation+41 (0) 79 365 57 48 - 
http://blog.ffwll.ch
> 

Does this mean the system is doing RGB full range to limited range
compression on the raw RGB data it receives from an application?

Ie a video player that want to be able to handle blacker than black
properly will need to force the GPU into fullrange output to avoid
the driver internal compression of the signal and handle that itself?

/Joakim