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List:       kde-devel
Subject:    Re: Dual-monitor support
From:       "Lucas Murray" <lmurray () undefinedfire ! com>
Date:       2009-01-03 13:25:05
Message-ID: f09827650901030525h66710a95o4037c02654a39cc9 () mail ! gmail ! com
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To sum up the discussion on IRC as it would be useful in this thread:

There are three types of multi-monitor support on X: Multihead,
Xinerama and XRandR.

Multihead came first and works by running a separate X server on every
screen. This is the most limited mode as it doesn't allow moving
windows between screen but it is guaranteed to work. Almost nobody
uses this anymore as both of the other modes will work in most cases
(Not all though) and have nicer advantages. Although this works fine
in KDE 3 no developer has worked on it for KDE 4 so we currently have
a major regression in that regard.

Next is Xinerama and it's implementations. On nVidia this is called
TwinView, on ATI it's Big Desktop, on Intel it's MergedFB. This is
what most people have been using for around ten years now. It is well
supported by KDE (I use it in KDE 3) and almost every other desktop
environment. Apparently this is becoming deprecated sometime in the
future as XRandR has gained all the required features.

Now we have XRandR, more specifically version 1.2 of the protocol.
This is the one that you will have problems on as it is still under
development and is quite complex. This is the only mode that allows
you to add, remove or resize monitors while the X server is running
and is the one that will make KDE act all weird and unstable. I've
never used this mode myself so I'm a little rusty on how it works but
I think nVidia also calls this TwinView in it's configuration settings
so that's why some people are saying that their "TwinView is broken".
The KDE Kephal project is aimed to make it easier for applications and
the workspace environment to support this mode.

If you want multi-monitor to work on KDE 4 with any degree of
stability you will need to be using a Xinerama implementation (Things
will get a little confusing as you don't want the official "Xinerama"
but the one that your driver implements--which is the TwinView, Big
Desktop and MergedFB). There are plenty of tutorials out there that
will explain exactly what you will need to change in your xorg.conf to
get it working. I have also attached my nVidia development xorg.conf
just in case you get a little stuck, just be warned that it's slightly
more complex and larger than it needs to be and is very nVidia
specific. By default it will run in TwinView mode using the settings
that I use for my production machine.

Good luck,
    Lucas

On Wed, Dec 31, 2008 at 5:47 AM, Fale <fabiolocati@gmail.com> wrote:
> On marted=EC 30 dicembre 2008 17:23:01 Anne Wilson wrote:
>> I thought I had read in a blog this week that dual-monitor support is no=
w
>> ready. Either I was dreaming, or I'm searching in the wrong place. Could
>> someone please put me right about this? I need the info to answer a user=
.
>> Thanks
>>
>> Anne
> I had a very bad experience with a dual monitor in KDE4.2b2, and after I
> spoke with a very nice guy in #kwin (his name started with Z, iirc) that
> explaned me that if you start KDE and after you plug-in the monitor and y=
ou
> configure it from the System Setting you are using XRenderR that is under
> development but is not complete, while there is a way through Xorg to
> configure correctly the dual monitor (I don't had enough time to test thi=
s
> way)
> --
> Fabio A Locati
>
> Home: Segrate, Milan, Italy (GMT +1)
> Phone: +39-328-3799681
> MSN/Jabber/E-Mail: fabiolocati@gmail.com
>
> PGP Key: 9EF6 3C79 F6DF 76CD 770A 43A1 DCCB 415C 9656 3334
>
> Envolved in: KDE, OpenStreetMap, Ubuntu, Wikimedia
>
>>> Visit http://mail.kde.org/mailman/listinfo/kde-devel#unsub to unsubscri=
be
>>> <<
>
>

["xorg.conf" (application/octet-stream)]

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