[mythtv-users] mythtv SVN, and xorg w/ dual DISPLAYs (not twinview) questions

[Jonathan Rogers]

Gary Dezern wrote:
> Second - I read somewhere (on this list, I think) about a person running 
> X with two displays on their 5200 card, but rather than configuring them 
> with twinview, they did something so that each monitor was a seperate X 
> "display."  In other words, they have a DVI display attached to the 
> nv5200 as well as a CRT monitor.  When mythfrontend starts, it gets the 
> DVI (DFP) monitor (:1), and then a separate X is started on the CRT 
> (:0).  Anyway, I'm thinking about trying that out, but I can't seem to 
> find the original information on it.  An xorg sample would be great.  
> Are there any limitations as far as XvMC with that type of configuration?

Typically, one instance of the X server manages a display, which is
composed of one or more screens, a pointing device, and a keyboard
device. In a typical, single server configuration, that display will be
called ":0", which has an empty hostname part to the left of the colon,
indicating that the server is running locally, and a "0" indicating it's
display number zero. If there's only one screen in that display, it will
be named ":0.0". A second screen, typically a monitor connected to a
second output of the same video device or another video device under
control of the same server would be called ":0.1".

If, on the other hand, you have two instances of X running, each will
manage a display, one of which will be called ":0" and the other ":1".
This is often the case when one has multiple GUI logins and switches
between them with Ctrl-Alt-F?. In that case, the different X instances
are sharing the same physical devices.

It's not usually possible for multiple instances of X to share a video
device simultaneously, even to use different ports, so you want to
configure two screens as part of the same display. This is pretty
straightforward once you understand the concepts and X11 has been
designed to do this from the beginning, unlike more popular windowing
systems.

<URL:http://gentoo-wiki.com/HOWTO_Dual_Monitors>

That Howto is in the Gentoo Wiki, but contains very little
Gentoo-specific information. You probably don't need or want Xinerama,
so read the section about multiple screens.

Jonathan Rogers