Bug 13969

What's the difference between this bug and bug#12656?
Please don't stick to the old xorg.conf, which won't work with the new intel driver. Instead, please looked at the guide at http://intellinuxgraphics.org/dualhead.html.
If you believe you've been using the right xorg.conf, please attach it.

the differnce is: I don't use xinerama:
And I've studied intensely all available info docus (incl. your link!) but nowhere infos how to realize this 'twin' configuration (x11-drivers/xf86-video-i810-1.7.4).
With i810 version >= 2 (up to 2.2.0) I'm *not* able to reproduce the old 'twin' configuration with two *independent* desktops!
(current versions: xorg-server 1.4.0.90; kernel 2.6.23)
Isn't it intended to implement the functionality of previous versions of the driver within the actual version too?
Unfortunately I'm not able to show you the *new* xorg version because I found *no* possibility to set up a static twin config. I only could setup the clone config and switch between the two minitors via xrandr.
(indeed the new driver crashes with the unmodified old xorg.conf)
------------ key points of *old* config ---------
Section "Device"
    Identifier    "Intel 0"
    Driver        "i810"
    Screen 0
    BusID        "PCI:0:2:0"
    VideoRam	  131072
    Option         "MonitorLayout" "CRT,LFP"
EndSection
Section "Device"
    Identifier    "Intel 1"
    Driver        "i810"
    Screen 1
    BusID        "PCI:0:2:0"
    VideoRam	  131072
    Option         "MonitorLayout" "CRT,LFP"
EndSection
Section "ServerLayout"
    Identifier     "Dual head Layout"
    Screen    0    "Internal Screen" 0 0
    Screen    1    "External Screen" RightOf "Internal Screen"
EndSection

I think, your 'twin' just means 'extended desktop' mentioned at http://intellinuxgraphics.org/dualhead.html.

You can firstly try sth. like:
xrandr --output VGA --left-of LVDS

Created attachment 13617 [details]
Xorg configuration V1.7.4/V2.2.0

Created attachment 13618 [details]
X log file driver version 1.7.4 ('twin' fnctional)

Created attachment 13619 [details]
X log file driver version 2.2.0 ('Clone' display)

sorry - but it's *not* the 'extended desktop' !
What I need are two *independent* desktops: different size, different resolution, different dpi values!
I've just tested some hours the configs (1.7.4 vs 2.2.0) again:
Coming from scratch (concerning V2.2) I was able to generate a desktop spanning over the two monitors *but* only vertical (horizontal is 2*1280 >2048 maximum allowed) and *not* separated: separation means *two* logical X-displays [:0.0 and :0.1];
than I adapted the xorg.conf reversely for V1.7.4 and as you can se in the attached file that only *minor* differences exist:
- V2.2 doesn't know 'MonitorLayout' (in my mind the crucial point)
- V2.2 has a different behaviour concerning the option 'Below':
-- in the Monitor section it results in 'spanning' (aka 'extended desktop')
-- in the server Layout section it results in 'cloning' (same content on both)
For your info I've attached 3 Xorg.log files

Created attachment 13620 [details]
X log file driver version 2.2.0 (vertical 'Extended' display)

We're not going to support multiple screens (multiple separated desktops). we've got reasonable standards in place for dealing with multiple monitors in a
single screen. 

Resolving the 2048 limits for DRI on pre-i965 hw is on our TODO list.