[mythtv-users] Start MythTV on Display I want (and if not there, next one I want)

John Finlay finlay at moeraki.com
Wed Jan 14 08:32:23 UTC 2009

Allen Edwards wrote:
>> I don't have a good understanding of how your system is set up. Do you
>> restart X each time you want to use the system? I have that impression. Is
>> the LCD always on i.e. available in both cases? Can you send your whole
>> xorg.conf file? What mods to the xorg.conf file have you tried?
>> John
> First to answer Nick's question:
> Video card is ASUS EN6200LE TC1G/TD/512M GeForce 6200LE 512MB 64-bit
> GDDR2 PCI Express x16 Video Card
> Deiver is 173.14.12
> Now to John's:
> Here is how I use the system.  Normally, myth is on the TV and the LCD
> is running Firefox and the projector is off and the DVI cable is
> switched to a DVD player (not myth).
> When I want to use the projector, I switch it to myth and restart X.
> That works great.  The LCD can still run firefox or be turned off,
> whatever.
> When done with the projector I switch it to the DVD player and I
> restart X.  Then I exit myth on the LCD and start myth on the TV.  I
> start it by using the mouse on the TV desktop and clicking on
> mythfrontend, which I can't read so have to remember where it is.  We
> are then back to the normal condition.  This is a pain and not
> something I can expect my wife to do.
> The only thing I have tried that is not represented by the xorg.conf
> file is Option "ConnectedMonitor".  I tried "TV-0", "DFP" in the
> display sections to near disastrous results.  I saw some Google posts
> that this option doesn't work so I quit experimenting with it.  I have
> past experience with the nvidia readme and know it is out of date so
> decided to quit guessing at solutions and ask.
> The problem is that my configuration isn't static.  The projector
> comes and goes and when it is there I want it to get myth, which it
> does.  When it is missing, I want the TV to get myth and instead the
> LCD gets it.  I can't instruct the system to put myth anywhere
> specific because what I want changes.  My goal with the xorg.conf file
> below was to change the priority that the Nvidia card uses to decide
> where to put the system by placing the various displays in the correct
> numerical order.  Doesn't work that way.
> My xorg.conf file is below.

I'm thinking that when you start X with the projector that all the 
screens are assigned as you spec'd, but when the projector is off, X 
can't find the DFP for "Screen 0" which is used for screen 0 and so it 
goes thru the default list to find a display device to use with screen 
0. Since the default list starts with CRT it finds the CRT and uses it 
for screen 0 leaving the TV-0 for screen 1. Looking in the Xorg.0.log 
file after you restart X without the DFP should show how X determined 
the mapping of display devices to the screens. Assuming this is correct 
you could try to specify a different list using UseDisplayDevice in the 
"Screen 0" Screen section:

Option		"UseDisplayDevice"	"DFP,TV"

This should use the projector (DFP) if available or use the TV (TV) if not. My read of the Nvidia docs suggests that UseDisplayDevice is a Screen option not a Device option (the overloading of names seems confusing).


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