[mythtv-users] DVI Output to HDTV

Tom Greer trgreer at gmail.com
Sat Mar 3 01:06:55 UTC 2007

 On 3/2/07, Ed O'Brien <ed3120[at]yahoo.com> wrote:
> Is anyone out there using DVI output successfully to their HDTV?
> I had my 1080i modeline working perfectly on the VGA out, and now I'm
> trying to switch to DVI out. I added the following lines to my xorg.confand I can get a signal, but only a 480p signal, despite my
> xorg.conf being configured to put out a 1080i modeline. (which works by
> default on my VGA out)
> Option "ConnectedMonitor" "DFP"
> Option "UseDisplayDevice" "DFP-0"
> Any ideas?
> Thanks,
> Ed


The key to solving your mystery is in the /var/log/Xorg.0.log file.

You should find a section that records what happens when the Xserver
processes the xorg.conf file and sets the video mode.  Here are
snippets of the interesting sections from mine.

Here is the section where the card and the display device are detected
and the modelines are processed.

(II) NVIDIA(0): NVIDIA GPU GeForce FX 5200 at PCI:1:0:0 (GPU-0)
(--) NVIDIA(0): Memory: 131072 kBytes
(--) NVIDIA(0): VideoBIOS:
(II) NVIDIA(0): Detected AGP rate: 8X
(--) NVIDIA(0): Interlaced video modes are supported on this GPU
(--) NVIDIA(0): Connected display device(s) on GeForce FX 5200 at PCI:1:0:0:
(--) NVIDIA(0):     PANASONIC-TV (DFP-0)
(--) NVIDIA(0): PANASONIC-TV (DFP-0): 135.0 MHz maximum pixel clock
(--) NVIDIA(0): PANASONIC-TV (DFP-0): Internal Single Link TMDS
(II) NVIDIA(0): Option "UseDisplayDevice" "DFP" converted to "DFP-0".
(II) NVIDIA(0): Assigned Display Device: DFP-0
(II) NVIDIA(0): Validated modes:
(II) NVIDIA(0):     "856x480"
(II) NVIDIA(0): Virtual screen size determined to be 856 x 480
(**) NVIDIA(0): DPI set to (100, 100); computed from "DPI" X config option

A little ways down, the video mode is actually set.

(II) NVIDIA(0): Setting mode "856x480"

I've been down the road before where X rejected my custom modelines
were rejected.  This was because the modelines specified would result
in output to the display that was outside the ranges specified by the

If I recall correctly, you should see error messages that your custom
modeline(s) are not valid and that some default mode is being set.

My memory may be faulty, so if you don't find what I'm describing,
then post what you do see - and we will work from there.


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