[mythtv-users] mythtv switching to strange modeline

[Marco Nelissen]

Using the latest beta nvidia driver (I was unable to get the latest non-beta
driver to do 1080i), I'm running into a problem: when X first starts it
switches to the 1080i modeline that I defined in xorg.conf, however when
mythtv launches, it switches to a modeline that I didn't define, and that
X didn't even validate as far as I can tell.
In my xorg.conf, I define the following modes:

    ModeLine       "ATSC-1080-59.94i" 74.2 1920 1960 2016 2200 1080 1082 1088 1125 interlace
    ModeLine       "ATSC-1080-60i" 74.2 1920 1960 2016 2200 1080 1082 1088 1125 interlace
    ModeLine       "ATSC-720-59.94p" 74.2 1280 1320 1376 1648 720 722 728 750
    ModeLine       "ATSC-720-60p" 74.2 1280 1320 1376 1648 720 722 728 750
    ModeLine       "ATSC-480-59.94i" 12.0 640 664 736 760 480 484 492 525 interlace
    ModeLine       "ATSC-480-60i" 12.0 640 664 736 760 480 484 492 525 interlace
    ModeLine       "ATSC-480-59.94p" 23.9 640 664 736 760 480 484 492 525
    ModeLine       "ATSC-480-60p" 23.9 640 664 736 760 480 484 492 525                       

In Xorg.0.log I see:

(II) NVIDIA(0): Assigned Display Device: DFP-0
(WW) NVIDIA(0): No valid modes for "NTSCspec-59.94i"; removing.
(WW) NVIDIA(0): No valid modes for "NTSCspec-59.94p"; removing.
(WW) NVIDIA(0): No valid modes for "1280x1024"; removing.
(II) NVIDIA(0): Validated modes:
(II) NVIDIA(0):     "ATSC-1080-59.94i"
(II) NVIDIA(0):     "ATSC-1080-60i"
(II) NVIDIA(0):     "ATSC-720-59.94p"
(II) NVIDIA(0):     "ATSC-720-60p"
(II) NVIDIA(0):     "ATSC-480-59.94i"
(II) NVIDIA(0):     "ATSC-480-59.94p"
(II) NVIDIA(0):     "ATSC-480-60i"
(II) NVIDIA(0):     "ATSC-480-60p"
(II) NVIDIA(0):     "1024x768"
(II) NVIDIA(0):     "800x600"
(II) NVIDIA(0):     "640x480"
(II) NVIDIA(0): Virtual screen size determined to be 1920 x 1080
(--) NVIDIA(0): DPI set to (59, 59); computed from "UseEdidDpi" X config
(--) NVIDIA(0):     option
(--) Depth 24 pixmap format is 32 bpp           
<snip>
(II) NVIDIA(0): Setting mode "ATSC-1080-59.94i"
<snip>
(II) NVIDIA(0): Setting mode "1920x1080_120i_0"

Questions: where do these other modes (640x480, 800x600, 1024x768 and 
1920x1080_120i_0) come from, and how come it switches to a mode that
wasn't even validated?