Can't get 1920x1200 with FC5+945G

[metagroboliser]

Folks,

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"
        ## modeline explained http://www.tldp.org/HOWTO/XFree86-Video-Timings-HOWTO/synth.ht$        
        ## also see http://gentoo-wiki.com/HOWTO_Widescreen_Resolutions_(WSXGA)
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. Strangely enough, if I perform these steps with 1680x1050 instead of 1920x1200, everything works as expected ... i.e, Gnome boots up nicely in 1680x1050. (Keep in mind that 1680x1050 is another non-standard, widescreen resolution, just like 1920x1200).

So, for some obscure reason, the 915resolution hack, the xorg.conf, the modelines etc seem to be working fine ... except for 1920x1200! I am at a total loss.

Any ideas?

[Juan Pablo]

Try setting the depth to 16 instead of 24

[metagroboliser]

Thanks for the suggestion. Yes, I did try with 16-bit ... no joy unfortunately. Does anything else come to mind?

[metagroboliser]

[UPDATE]:

Here is something potentially incriminating from the Xorg 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 first post above) clearly shows the 1920x1200 mode as being present in the BIOS.

What could be going on here? Would it be the driver (xorg-x11-drv-i810.1.6.0) or the server (
xorg-x11-server-Xorg.1.1.1-47) that isn't being able to pick up the high resolution mode from the BIOS?

[UPDATE #2]

Ok, the findings above are now confirmed:

$ 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

So here's our problem statement then: for i810/Xorg 7.1, 915resolution and xrandr do not agree on video BIOS modes.

Where to go from here?