Maybe one more piece of information I can post here. Xdpyinfo does not talk xinerama (unlike xscreensaver). A typical output is the following:
name of display: :0.0
version number: 11.0
vendor string: The X.Org Foundation
vendor release number: 10400090
X.Org version: 1.4.0.90
maximum request size: 16777212 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 0x1e00022, revert to Parent
number of extensions: 33
BIG-REQUESTS
Composite
DAMAGE
DOUBLE-BUFFER
DPMS
Extended-Visual-Information
GLX
MIT-SCREEN-SAVER
MIT-SHM
MIT-SUNDRY-NONSTANDARD
RANDR
RECORD
RENDER
SECURITY
SGI-GLX
SHAPE
SYNC
TOG-CUP
X-Resource
XAccessControlExtension
XC-APPGROUP
XC-MISC
XFIXES
XFree86-Bigfont
XFree86-DGA
XFree86-DRI
XFree86-Misc
XFree86-VidModeExtension
XINERAMA
XInputExtension
XKEYBOARD
XTEST
XVideo
default screen number: 0
number of screens: 1
screen #0:
print screen: no
dimensions: 1440x900 pixels (287x180 millimeters)
resolution: 127x127 dots per inch
depths (7): 24, 1, 4, 8, 15, 16, 32
root window id: 0x57
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: 0xda7f3f
KeyPressMask KeyReleaseMask ButtonPressMask
ButtonReleaseMask EnterWindowMask LeaveWindowMask
Button1MotionMask Button2MotionMask Button3MotionMask
Button4MotionMask Button5MotionMask ButtonMotionMask
KeymapStateMask StructureNotifyMask SubstructureNotifyMask
SubstructureRedirectMask PropertyChangeMask ColormapChangeMask
number of visuals: 17
default visual id: 0x23
visual:
visual id: 0x23
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: 0x24
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: 0x25
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: 0x26
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: 0x27
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: 0x28
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: 0x29
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: 0x2a
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: 0x2b
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
visual:
visual id: 0x2c
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
visual:
visual id: 0x2d
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
visual:
visual id: 0x2e
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
visual:
visual id: 0x2f
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
visual:
visual id: 0x30
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
visual:
visual id: 0x31
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
visual:
visual id: 0x32
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
visual:
visual id: 0x55
class: TrueColor
depth: 32 planes
available colormap entries: 256 per subfield
red, green, blue masks: 0xff0000, 0xff00, 0xff
significant bits in color specification: 8 bits