I'm trying to get MythTV going and I'm having a problem configuring X to correctly set the resolution on the TV. (I am getting output on the TV but it's in 4:3 not 16:9 ratio.)

I cannot see what I am doing wrong! Can someone please give me a hint?

Distro if Fedora Rawhide (pre-10 "bleeding edge"). X version info (some of):

==== start ====
$ grep xorg-x11-server /var/log/rpmpkgs
xorg-x11-server-common-1.5.1-10.fc10.x86_64.rpm
xorg-x11-server-utils-7.4-3.fc10.x86_64.rpm
xorg-x11-server-Xorg-1.5.1-10.fc10.x86_64.rpm
==== end ====

My xorg.conf is:
==== start ====
Section "ServerLayout"
Identifier "Multi-Head"
Screen 0 "Desktop" 0 0
Screen 1 "MythTV" RightOf "Desktop"
InputDevice "Keyboard" "CoreKeyboard"
InputDevice "Mouse" "CorePointer"
EndSection

Section "Files"
ModulePath "/usr/lib64/xorg/modules/extensions"
ModulePath "/usr/lib64/xorg/modules"
FontPath "/usr/share/fonts/default/Type1"
EndSection

Section "Module"
Load "dbe"
Load "extmod"
Load "fbdevhw"
Load "freetype"
Load "glx"
EndSection

Section "ServerFlags"
Option "Xinerama" "0"
EndSection

Section "InputDevice"
Identifier "Mouse"
Driver "mouse"
Option "Protocol" "auto"
Option "Device" "/dev/input/mice"
Option "Emulate3Buttons" "no"
Option "ZAxisMapping" "4 5"
EndSection

Section "InputDevice"
Identifier "Keyboard"
Driver "kbd"
Option "XkbLayout" "us"
Option "XkbModel" "pc105"
EndSection

Section "Device"
Identifier "GF9600_GSO_Samsung"
Driver "nvidia"
VendorName "NVIDIA Corporation"
BusID "PCI:1:0:0"
Option "UseEvents" "True"
Screen 0
EndSection

Section "Device"
Identifier "GF9600_GSO_TV"
Driver "nvidia"
VendorName "NVIDIA Corporation"
BusID "PCI:1:0:0"
Option "UseEvents" "True"
Screen 1
EndSection

Section "Monitor"
Identifier "Samsung"
VendorName "Samsung"
ModelName "SyncMaster 940BW"
HorizSync 30.0 - 81.0
VertRefresh 56.0 - 75.0
Option "DPMS"
EndSection

Section "Monitor"
Identifier "LG_TV"
VendorName "LG"
ModelName "LG42LB2DE"
Modeline "1920x1080" 176.92 1920 2008 2224 2632 1080 1080 1083 1120
Modeline "1080" 182.01 1920 1952 2640 2672 1080 1102 1113 1135
Modeline "1080i" 148.50 1920 2008 2052 2200 1080 1084 1089 1125 +hsync -vsync
EndSection

Section "Screen"
Identifier "Desktop"
Device "GF9600_GSO_Samsung"
Monitor "Samsung"
DefaultDepth 24
SubSection "Display"
Depth 24
EndSubSection
EndSection

Section "Screen"
Identifier "MythTV"
Device "GF9600_GSO_TV"
Monitor "LG_TV"
==== end ====

The Xorg.0.log file is, in part:
==== start ====
(WW) NVIDIA(GPU-0): Unable to read EDID for display device CRT-1
(II) NVIDIA(0): NVIDIA GPU GeForce 9600 GSO (G92) at PCI:1:0:0 (GPU-0)
(--) NVIDIA(0): Memory: 393216 kBytes
(--) NVIDIA(0): VideoBIOS: 62.92.23.00.10
(II) NVIDIA(0): Detected PCI Express Link width: 16X
(--) NVIDIA(0): Interlaced video modes are supported on this GPU
(--) NVIDIA(0): Connected display device(s) on GeForce 9600 GSO at PCI:1:0:0:
(--) NVIDIA(0): Samsung SyncMaster (CRT-0)
(--) NVIDIA(0): CRT-1
(--) NVIDIA(0): Samsung SyncMaster (CRT-0): 400.0 MHz maximum pixel clock
(--) NVIDIA(0): CRT-1: 400.0 MHz maximum pixel clock
(II) NVIDIA(0): Assigned Display Device: CRT-0
(==) NVIDIA(0):
(==) NVIDIA(0): No modes were requested; the default mode "nvidia-auto-select"
(==) NVIDIA(0): will be used as the requested mode.
(==) NVIDIA(0):
(II) NVIDIA(0): Validated modes:
(II) NVIDIA(0): "nvidia-auto-select"
(II) NVIDIA(0): Virtual screen size determined to be 1440 x 900
(--) NVIDIA(0): DPI set to (89, 87); computed from "UseEdidDpi" X config
(--) NVIDIA(0): option
(==) NVIDIA(0): Enabling 32-bit ARGB GLX visuals.
(**) NVIDIA(1): Depth 24, (--) framebuffer bpp 32
(==) NVIDIA(1): RGB weight 888
(==) NVIDIA(1): Default visual is TrueColor
(==) NVIDIA(1): Using gamma correction (1.0, 1.0, 1.0)
(**) NVIDIA(1): Option "UseEvents" "True"
(**) NVIDIA(1): Enabling RENDER acceleration
(II) NVIDIA(1): NVIDIA GPU GeForce 9600 GSO (G92) at PCI:1:0:0 (GPU-0)
(--) NVIDIA(1): Memory: 393216 kBytes
(--) NVIDIA(1): VideoBIOS: 62.92.23.00.10
(II) NVIDIA(1): Detected PCI Express Link width: 16X
(--) NVIDIA(1): Interlaced video modes are supported on this GPU
(--) NVIDIA(1): Connected display device(s) on GeForce 9600 GSO at PCI:1:0:0:
(--) NVIDIA(1): Samsung SyncMaster (CRT-0)
(--) NVIDIA(1): CRT-1
(--) NVIDIA(1): Samsung SyncMaster (CRT-0): 400.0 MHz maximum pixel clock
(--) NVIDIA(1): CRT-1: 400.0 MHz maximum pixel clock
(II) NVIDIA(1): Assigned Display Device: CRT-1
(WW) NVIDIA(1): No valid modes for "1080"; removing.
(WW) NVIDIA(1): No valid modes for "1080i"; removing.
(WW) NVIDIA(1): No valid modes for "1920x1080"; removing.
(WW) NVIDIA(1):
(WW) NVIDIA(1): Unable to validate any modes; falling back to the default mode
(WW) NVIDIA(1): "nvidia-auto-select".
(WW) NVIDIA(1):
(II) NVIDIA(1): Validated modes:
(II) NVIDIA(1): "nvidia-auto-select"
(II) NVIDIA(1): Virtual screen size determined to be 640 x 480
(WW) NVIDIA(1): Unable to get display device CRT-1's EDID; cannot compute DPI
(WW) NVIDIA(1): from CRT-1's EDID.
(==) NVIDIA(1): DPI set to (75, 75); computed from built-in default
(==) NVIDIA(1): Enabling 32-bit ARGB GLX visuals.
(--) Depth 24 pixmap format is 32 bpp
==== end ====

Well, as you can see...
...you're getting a 640x480 because...
...your graphics card refuses to use the modes you declared.

In my case I am running as well a PC (barebone Asus) connected to a LCD-TV using a nVidia GPU, but I am using http://mymediasystem.org as I am only interested in watching movies which are stored locally - I gave up with MythTV as it didn't fit my needs.
In order to get a 1080p resolution (but my TV is actually able to display only 720p) I use the following xorg.conf:
Afterwards in Xorg.0.log all I see about the resolution is:
So, as you see in the "Monitor"-section I don't have any modeline set but just specify the range of frequencies that can be set - the nVidia-GPU sets the frequencies on its own after reading the EDID of the TV - works great with all the nVidia-GPUs I have (notebook, desktop-pc).
One more thing is that I explicitly set the desired resolution in the "Screen"-section.
Give it a try.

I have heard that NVidia settings in your xorg.conf cant be standard "1920x1080" i think that you can append _xx where xx is your resolution or even some arbitrary number to the end of "1920x1080" so it would read "1920x1080_60". I think i was reading it on debian's forum earlier tonight so it is worth a try if you're still having problems.

hi gone_bush FIRST Fedora 10 IS NOT DONE yet and ONLY some things are working
do not use a unfinished PRE release to build a mythtv system