Ok here's a description of my setup, just for clarity's sake. I have two LCD monitors (Dell 1702FP and Planar 181) plugged into one AGP graphics card (Radeon 9700 Pro). Whenever I'm working on the command line, both monitors show the exact same thing. They both have a signal. I configured XF86Config and started X.

As soon as X starts up, the primary monitor (Dell 1702FP) loses its signal and the LED on the front turns orange. X runs solely on the secondary monitor (Planar 181). As soon as the X session ends, the Dell regains its signal.

At first I attributed this to how I configured X, even though both monitors are similar enough that they have pretty much the same horizontal sync and vertical refresh ranges. However, I just tested if this was true by unplugging the Planar and running Linux with only one monitor, the Dell. When I started X, it still lost its signal. If I didn't have a second monitor, X wouldn't work for me at all.

I know the factory specs and have configured X within its horizontal sync and vertical refresh ranges, but the problem still persists. Any ideas?

While on the flat-screen, run
xdpyinfo
just to make sure it actually is on
the settings you think it's using ...


Cheers,
Tink

Okay, I hooked up both monitors and started X. Once again only the secondary monitor, the Planar, had a signal during the X session. I ran xdpyinfo and this is the output:

name of display: :0.0
version number: 11.0
vendor string: The XFree86 Project, Inc
vendor release number: 40300000
XFree86 version: 4.3.0
maximum request size: 4194300 bytes
motion buffer size: 256
bitmap unit, bit order, padding: 32, LSBFirst, 32
image byte order: LSBFirst
number of supported pixmap formats: 7
supported pixmap formats:
depth 1, bits_per_pixel 1, scanline_pad 32
depth 4, bits_per_pixel 8, scanline_pad 32
depth 8, bits_per_pixel 8, scanline_pad 32
depth 15, bits_per_pixel 16, scanline_pad 32
depth 16, bits_per_pixel 16, scanline_pad 32
depth 24, bits_per_pixel 32, scanline_pad 32
depth 32, bits_per_pixel 32, scanline_pad 32
keycode range: minimum 8, maximum 255
focus: window 0x1c00005, revert to PointerRoot
number of extensions: 25
BIG-REQUESTS
DOUBLE-BUFFER
DPMS
Extended-Visual-Information
FontCache
LBX
MIT-SCREEN-SAVER
MIT-SHM
MIT-SUNDRY-NONSTANDARD
RANDR
RENDER
SECURITY
SHAPE
SYNC
TOG-CUP
X-Resource
XC-APPGROUP
XC-MISC
XFree86-Bigfont
XFree86-Misc
XFree86-VidModeExtension
XInputExtension
XKEYBOARD
XTEST
XVideo
default screen number: 0
number of screens: 1

screen #0:
dimensions: 1280x1024 pixels (342x271 millimeters)
resolution: 95x96 dots per inch
depths (7): 24, 1, 4, 8, 15, 16, 32
root window id: 0x38
depth of root window: 24 planes
number of colormaps: minimum 1, maximum 1
default colormap: 0x20
default number of colormap cells: 256
preallocated pixels: black 0, white 16777215
options: backing-store NO, save-unders NO
largest cursor: 64x64
current input event mask: 0xd84031
KeyPressMask EnterWindowMask LeaveWindowMask
KeymapStateMask SubstructureNotifyMask SubstructureRedirectMask
PropertyChangeMask ColormapChangeMask
number of visuals: 2
default visual id: 0x21
visual:
visual id: 0x21
class: TrueColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 8 bits
visual:
visual id: 0x22
class: DirectColor
depth: 24 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 8 bits

I don't see anything out of the ordinary here, granted I don't know what half of it means. Any ideas? Is there an extension I'm missing or something?

I'm guessing there would be no reason for a monitor not to work in Linux. Here is some more info on it.

Monitor
Windows description......... Plug and Play Monitor
Manufacturer description.... DELL 1702FP
Manufacturer................ Dell
————————————————————————————
Plug and Play ID............ DEL3006
Serial number............... 9G0772B6D1UC
————————————————————————————
Manufacture date............ 2002, ISO week 45
EDID revision............... 1.3
Display type and signal..... Digital
Sync input support.......... (n/a)
Screen size................. 340 x 270 mm (~18")
Power management............ Standby, Suspend, Active off/sleep

Color characteristics
Display gamma............... 2.40
Red chromaticity............ Rx 0.634 - Ry 0.354
Green chromaticity.......... Gx 0.304 - Gy 0.581
Blue chromaticity........... Bx 0.143 - By 0.102
White point (default)....... Wx 0.318 - Wy 0.339

Timing characteristics
VESA GTF support............ Not supported
Horizontal scan range....... 30-80kHz
Vertical scan range......... 56-76Hz
Video bandwidth............. 140MHz
Timing recommendation....... 1280x1024 at 60Hz
Modeline................ "1280x1024" 108.000 1280 1328 1440 1688 1024 1025 1028 1066 +hsync +vsync

Standard timings supported
640 x 480 at 60Hz - IBM VGA
640 x 480 at 75Hz - VESA
720 x 400 at 70Hz - IBM VGA
800 x 600 at 60Hz - VESA
800 x 600 at 75Hz - VESA
1024 x 768 at 60Hz - VESA
1024 x 768 at 75Hz - VESA
1152 x 864 at 75Hz - VESA
1280 x 1024 at 60Hz - Dell
1280 x 1024 at 60Hz - VESA
1280 x 1024 at 75Hz - VESA

Raw EDID (1)
00: 00 FF FF FF FF FF FF 00 10 AC 06 30 43 55 31 44
10: 2D 0C 01 03 E0 22 1B 8C EA 6F 8B A2 5A 4D 94 24
20: 1A 51 56 A5 4B 00 81 80 71 4F 01 01 01 01 01 01
30: 01 01 01 01 01 01 30 2A 00 98 51 00 2A 40 30 70
40: 13 00 52 0E 11 00 00 1E 00 00 00 FF 00 39 47 30
50: 37 37 32 42 36 44 31 55 43 0A 00 00 00 FC 00 44
60: 45 4C 4C 20 31 37 30 32 46 50 0A 20 00 00 00 FD
70: 00 38 4C 1E 50 0E 00 0A 20 20 20 20 20 20 00 63

Display adapter
Adapter description......... RADEON 9700 PRO
Adapter device ID........... 0x4E441002
Display settings............ 1280x1024, 32bpp

User/computer information
Registered user name........ Gregory Himes
Registered organization..... Statoil
Network user name........... Carlton
Network computer name....... DIMENSION
Windows version ............ Windows XP
Windows build .............. 5.01.2600
Installation date .......... 2/23/2104 10:00:28 AM