[mythtv-users] Semi OT: xorg.conf and 46" Samsung LCD help.

Paul Gallaway pgallaway at gmail.com
Tue Dec 2 17:39:23 UTC 2008

On Tue, Dec 2, 2008 at 12:19 AM, Jonny B <jon.the.wise.gdrive at gmail.com> wrote:
> If ANYBODY can see something in my xorg that could be changed, I would
> love to know... otherwise I'll just let it be for now. Thanks.

I'm no expert but I've spent many frustrating hours editing xorg.conf
files for various monitors and NVidia/ATI drivers so I have a few
troubleshooting suggestions/approaches I'd probably do next if in your
position. Perhaps you've already tried these but here it goes!

A couple questions you should ask yourself before you blindly accept my changes.

Are you using two monitors? Like the VGA out and SVIDEO out? If yes,
get the 1920x1080 going first and then come back to TwinView
configuration. If not disable TwinView/TV output stuff you have
enabled since you're not using it. If you're using SVIDEO out to your
LCD TV then there's no hope. SVideo won't support the resolution .

Also, from the reading I've done (just now) I don't think you use the
'TVStandard' option unless you are using the TV-out on the card. Newer
cards support component (with an adaptor) but guessing from the age of
your card you're probably limited to Svideo? Anyway, sounds like you
are connected via VGA and not SVideo or Component (though you didn't
explicitly say what connections you had). I think you should disable
the TV options. If you are using TwinView to send SVIDEO to a CRT then
deal with this after you solve the resolution problems. From my
[limited] understanding the MetaModes option is used to set different
resolutions on different devices so you'd send 1920x1080 to the LCD
and something less than that over SVideo.

I'd recommend giving the Kernel AGP module a try. Setting the NvAgp
option as 3 will try the Kernel module first and fallback to the
NVidia option second. '3' is the current default for newer drivers and
I assume the Kernel AGP module has had some improvements/revisions
since this driver was released circa 2006.

Section "Device"
   Identifier     "GeForce4000MX"
   Driver         "nvidia"
   VendorName     "NVIDIA Corporation"
   BoardName      "GeForce4 MX 4000"
#   change from '1' to '3' (or '2') to use linux kernel AGP module
   Option         "NvAgp" "3"
#   Disable TwinView when only using VGA
#   Option         "TwinView"
   Option         "RenderAccel" "true"
   Option         "UseEvents" "true"
   Option         "XvmcUsesTextures" "false"
# Use this TVStandard if connecting SVIDEO to NTSC - note the '-M' after NTSC
# for all NTSC locations accept Japan uses NTSC-J
  Option         "TVStandard" "NTSC-M"
# Use this TVStandard when connected to 1080P LCD etc. - probably
requires component connection?
#   Option         "TVStandard" "HD1080P"
#  Option         "TVOutFormat" "SVIDEO"
   Option         "DPI" "100x100"
#   Option         "MetaModes" "1920x1080; 1600x1200; 1360x768;
1280x1024; 1024x768; 800x600;"

It's all in the README from the driver you specified:

I'd leave this alone and be happy if the above suggestions work.

Have you tried enabling the custom modelines? If the above changes
work then I'd stick with what you have. Your modelines are currently
disabled. I've set LCDs up with and without custom modelines so I'm
not sure it matters.

My experience with a modeline generator (grt?) was that I had to
adjust HSync and Vsync +/- using trial and error to get some modelines
working. Not sure what these settings do and there's probably some
risk to your equipment if you don't read up on it.

One other thought: I don't know where you got the horizontal and
vertical refresh values you set in xorg. The help section in the
manual, the PC Display Modes section of manual, and your xorg values
all have different ranges. If you set this wrong you can harm
something so do so at your own risk! This is where modelines are
better as you don't need to know exactly what the range is to enable
all display modes. If you decide to set modelines you can comment
these ranges out. I think the values you have may be the safe default
values for VESA compliant monitors. Not sure?

It's well documented in your TV's manual. It will allow you adjust the
screen position among other things. You should probably run it after
any changes you make to xorg to make sure the screen is centred etc.
on your TV. May want to play with manual settings as well.

        all good things. all in good time.

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