Desculpa repetir o e-mail, mas da última vez eu me enrolei com as respostas e acabei "esquecendo" do tópico (eu respondi, mas não para a lista).
O problema é o seguinte:
Quando o GDM starta, ele abre em uma resolução diferente da configurada
(1152x768 ao invés de 1024x768). (e como meu monitor não a aguenta, ele
fica estranhamente reduzido no meio da tela)
Daí eu logo normalmente e a tela volta à resolução normal. (ou fica
na mesma resolução, e eu tenho que alterar pelo Sistema ->
Preferências -> Resolução de tela e escolher o 1024x768).
O conteúdo do xorg.conf é esse:
# /etc/X11/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 /etc/X11/xorg.conf manual page.
# (Type "man /etc/X11/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 "Files"
FontPath "/usr/share/fonts/X11/misc"
FontPath "/usr/X11R6/lib/X11/fonts/misc"
FontPath "/usr/share/fonts/X11/cyrillic"
FontPath "/usr/X11R6/lib/X11/fonts/cyrillic"
FontPath "/usr/share/fonts/X11/100dpi/:unscaled"
FontPath "/usr/X11R6/lib/X11/fonts/100dpi/:unscaled"
FontPath "/usr/share/fonts/X11/75dpi/:unscaled"
FontPath "/usr/X11R6/lib/X11/fonts/75dpi/:unscaled"
FontPath "/usr/share/fonts/X11/Type1"
FontPath "/usr/X11R6/lib/X11/fonts/Type1"
FontPath "/usr/share/fonts/X11/100dpi"
FontPath "/usr/X11R6/lib/X11/fonts/100dpi"
FontPath "/usr/share/fonts/X11/75dpi"
FontPath "/usr/X11R6/lib/X11/fonts/75dpi"
# path to defoma fonts
FontPath "/var/lib/defoma/x-ttcidfont-conf.d/dirs/TrueType"
EndSection
Section "Module"
Load "i2c"
Load "bitmap"
Load "ddc"
Load "dri"
Load "extmod"
Load "freetype"
Load "glx"
Load "int10"
Load "vbe"
EndSection
Section "InputDevice"
Identifier "Generic Keyboard"
Driver "kbd"
Option "CoreKeyboard"
Option "XkbRules" "xorg"
Option "XkbModel" "abnt2"
Option "XkbLayout" "br"
Option "XkbVariant" "abnt2"
EndSection
Section "InputDevice"
Identifier "Configured Mouse"
Driver "mouse"
Option "CorePointer"
Option "Device" "/dev/input/mice"
Option "Protocol" "ImPS/2"
Option "Emulate3Buttons" "true"
EndSection
Section "Device"
Identifier "Intel Corporation 82945G/GZ Integrated Graphics Controller"
Driver "i810"
# Driver "intel"
BusID "PCI:0:2:0"
Option "IgnoreEDID" "true"
EndSection
Section "Monitor"
Identifier "Monitor Genérico"
Option "DPMS"
HorizSync 28-102
VertRefresh 43-60
EndSection
Section "Screen"
Identifier "Default Screen"
Device "Intel Corporation 82945G/GZ Integrated Graphics Controller"
Monitor "Monitor Genérico"
DefaultDepth 24
SubSection "Display"
Depth 16
Modes "1024x768"
EndSubSection
SubSection "Display"
Depth 24
Modes "1024x768"
EndSubSection
EndSection
Section "ServerLayout"
Identifier "Default Layout"
Screen "Default Screen"
InputDevice "Generic Keyboard"
InputDevice "Configured Mouse"
EndSection
Section "DRI"
Mode 0666
EndSection
Obrigado, Rafael.