[mythtv-users] overscan compensating display manager?

[John and Holly Klug]

I don't believe it is possible to correct my HDMI TV with modeline 
changes, so what I would like is a display manager or window manager 
that runs under X on Linux that can be configured to not use the whole 
screen.

Looking at the readme for Linux and Windows from nvidia, in Linux they 
are completely silent on the topic of DVI overscan.  In the windows 
readme they say to go to control panel and configure the size of the 
desktop.

I am trying to set up Linux and eventually mythtv with a new motherboard 
with built-in hdmi and new binary nvidia driver.

Changing the Modeline causes the TV to go from progressive to interlace 
(I have no 1080p).  It appears that any change to modeline in 720p 
results in the TV displaying in 1080i, and startx -- -logverbose 6
doesn't yield any errors. Here is an example that modified my modeline 
slightly and threw the TV into 1080i:

Modeline       "1296x724 at 60" 75.13 1296 1328 1608 1640 724 739 746 761 
+hsync +vsync

This is 720p from EDID:
ModeLine       "720p" 74.25 1280 1390 1430 1650 720 725 730 750 +hsync 
+vsync

Driver results:
(II) NVIDIA(0): Assigned Display Device: DFP-0
(II) NVIDIA(0): Validated modes:
(II) NVIDIA(0):     "1296x724 at 60"
(II) NVIDIA(0): Virtual screen size determined to be 1296 x 724
(**) NVIDIA(0): DPI set to (125, 125); computed from "DPI" X config option
  ...
(II) NVIDIA(0): Setting mode "1296x724 at 60"
(II) Loading extension NV-GLX

I don't see any indication that it is going into 1080i mode in the 
Xorg.0.log file, but the raster lines are shimmering, and the TV reports 
1080i.

If there is no such thing as a desktop in Linux that can center itself 
and scale itself appropriately, is there a way to get the main panel 
into the field of view in KDE?  It seems to always be towards the edge 
of the screen.