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Old 01-22-2008, 12:51 PM   #1
Registered: Apr 2004
Location: USA
Distribution: Mint 19 Cinnamon
Posts: 64

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xorg.conf and LCD tv / monitor

my new samsung LN-T2653H LCD tv sort of works with my nvidia fx5200 card. The TV is connected via the VGA cable. However, there are several problems I need help with:

1. the tv emits a high-pitched whistle (quiet but noticeable) when displayng output from the PC. It does not do this while playing "regular" TV. This caused me to want to make sure my refresh rates and other settings were correct, thus I uncovered the following additional problems:

2. logging out of X and back in does not work. ctrl-alt-backspace provides a login screen, but entering the password results n a brief flash of a white screen with a mouse pointer, then a black screen with the TV reporting "unsupported mode." This is making it extremely hard to troubleshoot as I have to reboot the whole machine to test out different settings.

3. in the xorg.0.log file, there is a message of "unable to read EDID settings from display CRT-0" Why does it think my flat panel is a CRT? Could this be part of my problems?

4. also in xorg.0.log, it indicates a pixel clock of 135, but none of the recommended settings in my tv's manual go higher than 85. No clue how, whether or why to change this.

5. I have no idea whether I'm supposed to be using custom modelines or not, and if so, where to find one for this model of display (google no help here). I already had to remove / comment out the higher-resolution modelines that were there earlier, in order to get somethng other than a black screen and "unsupported mode" (this is a fresh install of ubuntu)

Help and guidance of any kind is appreciated~ more details about my setup are below if needed.

nvidia driver version: 100.14.19
linux version: ubuntu 64-bit gutsy 7.10
tv specs: says it has a "PC resoluton" of 1360x768. the tv is 720P. The manual provdes a list of resolutions and frequencies for which it says the screen image has been "optimized," but I can't translate these into a modeline b/c my understanding is a modeline needs 4 hsync and 4 vsync values, whereas the chart in my manual only provides one pair of settings per resolution (along with a clock value and polarity setting).

my xorg.conf [after I fiddled with it to reduce the resolution to get any output at all]

# nvidia-xconfig: X configuration file generated by nvidia-xconfig
# nvidia-xconfig: version 1.0 (buildmeister@builder26) Wed Sep 12 14:29:17 PDT 2007

# xorg.conf (xorg X Window System server configuration file)
# This file was generated by dexconf, the Debian X Configuration tool, using
# values from the debconf database.
# Edit this file with caution, and see the xorg.conf manual page.
# (Type "man xorg.conf" at the shell prompt.)
# This file is automatically updated on xserver-xorg package upgrades *only*
# if it has not been modified since the last upgrade of the xserver-xorg
# package.
# If you have edited this file but would like it to be automatically updated
# again, run the following command:
# sudo dpkg-reconfigure -phigh xserver-xorg

Section "ServerLayout"

# Uncomment if you have a wacom tablet
# InputDevice "stylus" "SendCoreEvents"
# InputDevice "cursor" "SendCoreEvents"
# InputDevice "eraser" "SendCoreEvents"
Identifier "Default Layout"
screen 0 "Default Screen" 0 0
Inputdevice "Generic Keyboard"
Inputdevice "Configured Mouse"

Section "Files"

Section "Module"
Load "glx"
Load "v4l"

Section "InputDevice"
Identifier "Generic Keyboard"
Driver "kbd"
Option "CoreKeyboard"
Option "XkbRules" "xorg"
Option "XkbModel" "pc105"
Option "XkbLayout" "us"

Section "InputDevice"
Identifier "Configured Mouse"
Driver "mouse"
Option "CorePointer"
Option "Device" "/dev/input/mice"
Option "Protocol" "ImPS/2"
Option "ZAxisMapping" "4 5"
Option "Emulate3Buttons" "true"

Section "InputDevice"
Identifier "stylus"
Driver "wacom"
Option "Device" "/dev/input/wacom"
Option "Type" "stylus"
Option "ForceDevice" "ISDV4"# Tablet PC ONLY

Section "InputDevice"
Identifier "eraser"
Driver "wacom"
Option "Device" "/dev/input/wacom"
Option "Type" "eraser"
Option "ForceDevice" "ISDV4"# Tablet PC ONLY

Section "InputDevice"
Identifier "cursor"
Driver "wacom"
Option "Device" "/dev/input/wacom"
Option "Type" "cursor"
Option "ForceDevice" "ISDV4"# Tablet PC ONLY

Section "Monitor"
Identifier "Generic Monitor"
Vendorname "Generic LCD Display"
Modelname "LCD Panel 1360x768"
Horizsync 31.5-48.0
Vertrefresh 56.0 - 65.0
modeline "800x600@56" 36.0 800 824 896 1024 600 601 603 625 +hsync +vsync
modeline "800x600@60" 40.0 800 840 968 1056 600 601 605 628 +hsync +vsync
# modeline "1280x768@60" 80.14 1280 1344 1480 1680 768 769 772 795 -hsync +vsync
# modeline "1280x720@60" 74.48 1280 1336 1472 1664 720 721 724 746 -hsync +vsync
Gamma 1.0

Section "Monitor"
Identifier "monitor1"
Vendorname "Plug 'n' Play"
Modelname "Plug 'n' Play"
modeline "640x480@60" 25.2 640 656 752 800 480 490 492 525 -vsync -hsync
Gamma 1.0

Section "Device"
Identifier "nVidia Corporation NV34 [GeForce FX 5200]"
Boardname "nv"
Busid "PCI:1:0:0"
Driver "nvidia"
Screen 0

Section "Device"
Identifier "device1"
Boardname "nv"
Busid "PCI:1:0:0"
Driver "nvidia"
Screen 1

Section "Screen"
Identifier "Default Screen"
Device "nVidia Corporation NV34 [GeForce FX 5200]"
Monitor "Generic Monitor"
Defaultdepth 24
SubSection "Display"
Depth 24
Virtual 800 600
Modes "800x600@60" "800x600@56"

Section "Screen"
Identifier "screen1"
Device "device1"
Monitor "monitor1"
Defaultdepth 24
SubSection "Display"
Depth 24
Modes "640x480@60"

Section "ServerFlags"


My xorg.0.log (relevant-looking part):

(--) 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): CRT-0
(--) NVIDIA(0): CRT-0: 350.0 MHz maximum pixel clock
(II) NVIDIA(0): Assigned Display Device: CRT-0
(II) NVIDIA(0): Validated modes:
(II) NVIDIA(0): "800x600@60"
(II) NVIDIA(0): "800x600@56"
(**) NVIDIA(0): Virtual screen size configured to be 800 x 600
(WW) NVIDIA(0): Unable to get display device CRT-0's EDID; cannot compute DPI
(WW) NVIDIA(0): from CRT-0's EDID.
(==) NVIDIA(0): DPI set to (75, 75); computed from built-in default
(==) NVIDIA(0): Enabling 32-bit ARGB GLX visuals.
(--) Depth 24 pixmap format is 32 bpp
Old 01-23-2008, 02:03 PM   #2
Senior Member
Registered: Jan 2006
Posts: 4,363

Rep: Reputation: 172Reputation: 172
Why are you trying to run the screen at such low resolutions? On lcds the screen actually always runs at the native resolution and the monitor hardware just resizes the incoming data to fit. As for the other modes that the monitor supports, you should not need any modlines. You should be able to just add the standard description (say "1360x768") and it will just pick it up.


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