Mailing List Archive: Two X displays without screen blanking? (Monitor and TVout)

Hello,

I was wondering if anyone knew how to stop X from blanking the screen
when switching displays. What I want to do is display one X screen on my
monitor an another display on my TV using the TV out on my GeForce3
card. I am able to do this by executing 'startx' on one console and then
'startx -- :1 -screen tvout' on another console. The second startx goes
to the TV out. Both X sessions launch no problem but I can view only one
at a time, The other screen goes blank. Is there anyway to keep both
screens visable? My main goal here is to have MythTV running on the
second display while still be able to use the computer on the first X
display.

Below are sections of my XFree config file that show the options used to
get TVout working:

Section "Monitor"
Identifier "TV"
HorizSync 30-50
VertRefresh 60
EndSection

Section "Screen"
Identifier "tvout"
#Device "geforce"
Device "NVIDIA GeForce3 (generic)"
Monitor "TV"
DefaultDepth 24

Option "TVStandard" "NTSC"
Option "ConnectedMonitor" "TV"
Option "NoLogo" "on"

Subsection "Display"
Depth 24
Modes "800x600"
ViewPort 0 0
EndSubsection
EndSection

Greg wrote
> What I want to do is display one X screen on my
> monitor an another display on my TV using the TV out on my GeForce3
> card. I am able to do this by executing 'startx' on one console and then
> 'startx -- :1 -screen tvout' on another console. The second startx goes
> to the TV out. Both X sessions launch no problem but I can view only one
> at a time, The other screen goes blank. Is there anyway to keep both
> screens visable? My main goal here is to have MythTV running on the
> second display while still be able to use the computer on the first X
> display.

Not going to be possible without serious changes/hacks to X.
It will only display one (VT) virtual terminal at a time. You
might find some info on this in the archive. I remember seeing
that someone linked a site where someone was writing their own
source code hacks to make something like this possible, but it
definitely isn't standard and will take some research on your
part to see if that is a path you want to explore.

An earlier thead discussing this can be found here:
http://gossamer-threads.com/archive/MythTV_C2/Dev_F10/Dual_%28simultaneous%29_use_of_MythTV_box_P55887/

Unfortunately, even if you get past that problem, the GeForce3
is not dual-headed, so it cannot display 2 seperate images on
the different outputs at the same time. I'm pretty sure it
cannot even display the *same* image on both the monitor and
TV outputs at the same time. Other models of nVidia-based
boards have varying capabilities in this regard. Cards based
on the GeForce2 MX chip are probably the most well supported
dual-headed GeForce cards.

-Chris