X11 server Virtual Desktop Support

[Adam Jackson]

On Sat, 2008-08-30 at 20:14 +0100, Keith Roberts wrote:

> ... I seem to have got the idea from somewhere that the 
> virtual keyword is not supported in xorg.conf anymore. I 
> think it was from a post on another mailing list where I 
> found this link:
> 
> https://bugs.freedesktop.org/show_bug.cgi?id=11418

So, there's two things here.

One is the Virtual keyword in xorg.conf.  At a base level, all that does
is define how much video memory to reserve for the logical screen.  It's
just a size.

The second thing is what the driver does with that space.  There are two
kinds of drivers, for purposes of this discussion we'll call them legacy
and randrful.  Legacy drivers can, at their option, enable a panning
mode, in which the Virtual size defines the size of the root window, and
the current cursor position is used to pan a viewport onto that root
window.  In randrful drivers, that functionality simply is not present.

(This is made slightly more confusing in the nv driver because it
manages to be either legacy or randrful, depending which kind of chip
it's driving.  G80 and newer chips - GeForce 8xxx and newer - are
randrful, and earlier are legacy.)

> BTW - is this the same X11 server code that Fedora uses? 
> There seems to be more than 1 version of the X11 server code 
> available for downloading.

Yes, it is.

> I have tried changing the above F9 Section "Screen" to:
> 
> Section "Screen"
>          Identifier "Screen0"
>          Device     "Videocard0"
>          DefaultDepth     24
>          SubSection "Display"
>                  Viewport   0 0
>                  Depth     24
>                  Virtual 800 1800
>                  Modes    "800x1800" "800x600" "640x480"
>          EndSubSection
> EndSection

That "800x1800" line in the Modes line isn't going to do what you want.
A Mode in the config file is a description of the region to display and
the timings of the synchronization regions at the edges.  You don't
_want_ to display 800x1800.

> But the font sizes are *way* to large. This is why I'm still 
> using F8.

Which sounds like we're just computing the dpi from the Virtual size
instead of the default mode size.  Merely a bug, but again, need to see
the log from the broken configuration to know for sure.

> The Xorg.0.log file (using startx -- -logverbose) tells me:
> 
> '''
> (WW) No monitor specified for screen "Screen0".
>          Using a default monitor configuration.
> '''
> 
> I think I need a Monitor section in the F9 xorg.conf to set 
> the font size with the DisplaySize keyword. I'm not sure how 
> to go about adding the Monitor section to the F9 xorg.conf 
> to implement this. Any suggestions would be greatly appreciated.

Section "Monitor"
    Identifier "Monitor0"
    # any settings you want...
EndSection

Section "Screen"
    Identifier "Screen0"
    Monitor "Monitor0"
    # the rest of your Screen section as above...
EndSection

- ajax