single logical screen EDID proposal

Kai-Uwe Behrmann ku.b at
Wed Apr 19 06:44:23 PDT 2006

The proposal is attached to bug #3910


Am 19.04.06, 09:29 +0200 schrieb Kai-Uwe Behrmann:

> EDID information describing inbuild display capabilities is stored 
> into one property in the root window of a X server.
> Single logical screen configurations with a unified root window across 
> all screens have just one root window to store such information for all 
> physical screens. Currently no EDID is stored in that root window at all 
> (tested with Xorg-6.8 and twinview style nvidia configuration).
> To let client side application access these valuable data, my proposal 
> suggests to use following behaviour
> 1. XFree86_DDC_EDID1_RAWDATA root property is created for the 0 (first)
>    screen. This is as is today.
> 2. XFree86_DDC_EDID1_RAWDATA_[1-9] properties follow up for each 
>    additional screen inside a single logical screen configuration. 
> The numbering in point 2 should follow the screen numbering.
> The advantage is the current behaviour remains for single physical 
> screen configurations and multi screen configurations with one root 
> window per physical screen.
> For single logical screen configurations the same information set would 
> then become available through the proposed additional properties.
> I followed the nomenclatura found in a older user manual.
> Even though termes used are a bit confusing like "screen" <-> "xinerama 
> screen" or physical versus logical. But this is possibly due to the 
> current transition to a Xinerama alike behaviour.
> regards
> Kai-Uwe Behrmann
>                                 + development for color management 
>                                 + imaging / panoramas
>                                 + email: ku.b at
>                                 +

More information about the xorg mailing list