Xinerama and Clone

Alex Deucher alexdeucher at
Mon Apr 10 06:13:35 PDT 2006

On 4/10/06, Lukas Hejtmanek <xhejtman at> wrote:
> Hello,
> what is the status of Xinerama? I noticed a request to change Xinerama so that
> mergefb and others would not be needed any more and people can use Xinerama
> instead.

An improved xinerama extension wouldn't replace mergedfb, it would
just simplify the code a bit and reduce the amount of duplication. 
This change would only apply to xinerama hints and whether the "real"
xinerama handles them or not.  Basically, it'd be nice to have
xinerama support more than just X screens on the backend so that we
could use the "real" xinerama extension to handle size, orientation,
hints in all cases instead of re-implementing xinerama in mergedfb

> So will it be possible to change Xinerama and single head on the fly?

you can already with xrandr and mergedfb to a certain extent.  You
just need to specify a mix of dualhead and clone metamodes. however,
you are limited to the largest mode defined.

> And related thing---what about a generic extension which allows to set and uset
> Clone mode in runtime---as many modern videocards support dual head
> configurations.

What do you mean?  switch between dualhead and clone? or change the
timings on the second crtc?  Unforunately, dynamic framebuffer and
output configuration still requires a fair amount of work.  We need a
good framebuffer memory manager to handle vram allocations for front
and other buffers, and we need an attribute system to handle the
reconfiguration requests.


> --
> Lukáš Hejtmánek

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