Xorg7 + i810 driver + 915resolution = still can't go above 1600x1200.

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I'm trying to get a new Conroe workstation up using a 945G motherboard
and a Dell 2405fpw (1920x1200 LCD) monitor. Unfortunately, I'm at wit's
end on how to get the LCD's native 1920x1200 res going with the i810
driver. Here's the rundown of what I've done so far:

1. The FC5 default driver (xorg-x11-drv-i810-1.4.1.3) couldn't do any
better than 1280x1024 no matter what I tried. A brief search on google
lead to pulling the 1.6 version from the development repo. (this brought
along Xorg-1.1.1-47.fc6). I could now do resolutions higher than 1600x1200.

2. Deployed 915resolution-0.5.2 and set up rc.local to substitute
1920x1200, resulting in:

$ sudo /usr/sbin/915resolution -l
Intel 800/900 Series VBIOS Hack : version 0.5.2

Chipset: 945G
BIOS: TYPE 1
Mode Table Offset: $C0000 + $269
Mode Table Entries: 27

Mode 30 : 640x480, 8 bits/pixel
Mode 32 : 800x600, 8 bits/pixel
Mode 34 : 1024x768, 8 bits/pixel
Mode 38 : 1280x1024, 8 bits/pixel
Mode 3a : 1600x1200, 8 bits/pixel
Mode 3c : 1920x1200, 8 bits/pixel
Mode 41 : 640x480, 16 bits/pixel
Mode 43 : 800x600, 16 bits/pixel
Mode 45 : 1024x768, 16 bits/pixel
Mode 49 : 1280x1024, 16 bits/pixel
Mode 4b : 1600x1200, 16 bits/pixel
Mode 4d : 1920x1200, 16 bits/pixel
Mode 50 : 640x480, 32 bits/pixel
Mode 52 : 800x600, 32 bits/pixel
Mode 54 : 1024x768, 32 bits/pixel
Mode 58 : 1280x1024, 32 bits/pixel
Mode 5a : 1600x1200, 32 bits/pixel
Mode 5c : 1920x1200, 32 bits/pixel

*Note* the successful injection of the 1920x1200 mode.

3. Relevant section of my xorg.conf:

Section "Monitor"

        Identifier   "Monitor0"
        VendorName   "Dell"
        ModelName    "Dell 2405FPW (Analog)"
        DisplaySize  519        324
        HorizSync    30.0 - 81.0
        VertRefresh  56.0 - 76.0
        ModeLine     "1920x1200" 154.0 1920 1968 2000 2080 1200 1203
1209 1235 -hsync +vsync
        Option      "dpms"
EndSection

Section "Device"
        Identifier  "Videocard0"
        Driver      "i810"
        VendorName  "Intel"
        BoardName   "Intel Corporation 945G Integrated Graphics Controller"
EndSection

Section "Screen"
        Identifier "Screen0"
        Device     "Videocard0"
        Monitor    "Monitor0"
        DefaultDepth     24
        SubSection "Display"
                Viewport   0 0
                Depth     24
                Modes    "1920x1200"
        EndSubSection
EndSection

*Note:* I created the ModeLine using /var/log/Xorg.0.log, and also
double checked other relevant entries against the log.

4. startx -> Xserver starts successfully, but in 1600x1200!

5. Now here is something potentially incriminating

>From /var/log/Xorg.0.log:

(II) I810(0): Printing DDC gathered Modelines:
...
(II) I810(0): Modeline "1920x1200"  154.00  1920 1968 2000 2080  1200
1203 1209 1235 -hsync +vsync
...
(II) I810(0): Not using mode "1920x1200" (no mode of this name)
...
(--) I810(0): Virtual size is 1600x1200 (pitch 2048)
(**) I810(0): *Built-in mode "1600x1200"
(**) I810(0):  Built-in mode "1280x1024"
(**) I810(0):  Built-in mode "1024x768"
(**) I810(0):  Built-in mode "800x600"
...

It looks like the monitor IS reporting 1920x1200, but it isn't being
used because the 'Built-in' modes (which I'm guessing are being pulled
from the video BIOS) aren't showing a corresponding mode. However, the
915resolution listing (see above) clearly shows the 1920x1200
mode as being present in the BIOS.

This is further confirmed by xrandr:

$ xrandr -q
 SZ:    Pixels          Physical       Refresh
*0   1600 x 1200   ( 521mm x 331mm )  *60
 1   1280 x 1024   ( 521mm x 331mm )   75
 2   1024 x 768    ( 521mm x 331mm )   75
 3    800 x 600    ( 521mm x 331mm )   75
Current rotation - normal
Current reflection - none
Rotations possible - normal left inverted right
Reflections possible - none

Apparently, Xorg isn't seeing the 1920x1200 mode despite the 1920x1200
mode being reported by the BIOS.

Where do I go from here?