nouveau and multimonitor with mutter problems

[Gianluca Cecchi]

Hello,
I'm trying here as F15 has been just released. Perhaps same problem in
rawhide too..
During latest days I have tested my XPS M1330 Dell laptop with nvidia
proprietary drivers and now I'm evaluating switching to nouveau.
I have final F15 x86_64.
No xorg.conf file and no nvidia rpm bits.
I connect a 19" monitor to vga.
Starting in fallback mode all is ok and I can configure laptop
(1280x800) under monitor (1280x1024).
In gdm the login box is inside laptop and I can see background inside
the monitor too.
After login my top bar is positioned at top of laptop display.
I can drag windows from top to bottom display crossing the top bar and
vice versa.
The status bar is at bottom of laptop.

If I set the default gnome 3 with effects, I have the same behaviour
at gdm login, and the same positioning of top bar after login.
But Inside the external monitor I see the background image, without
being able to put windows in this monitor.
When dragging a window it stops right under the top bar, no way. And
all new windows are opened inside laptop display.
If I use the classic Alt+drag operation I can traverse top bar and
arrive with top part of this window about half height of the external
monitor....

My nvidia adapter is:
01:00.0 VGA compatible controller: nVidia Corporation G86 [GeForce
8400M GS] (rev a1)

In system settings --> graphics I see the driver detected as
Gallium 0.4 on NV86

in both fallback mode and standard mode xrandr gives:
Screen 0: minimum 320 x 200, current 1280 x 1824, maximum 8192 x 8192
LVDS-1 connected 1280x800+0+1024 (normal left inverted right x axis y
axis) 287mm x 180mm
   1280x800       60.0*+
   1024x768       59.9
   800x600        59.9
   640x480        59.4
   720x400        59.6
   640x400        60.0
   640x350        59.8
VGA-1 connected 1280x1024+0+0 (normal left inverted right x axis y
axis) 338mm x 270mm
   1280x1024      60.0*+   75.0
   1152x864       75.0
   1024x768       75.1     70.1     60.0
   832x624        74.6
   800x600        72.2     75.0     60.3     56.2
   640x480        72.8     75.0     66.7     60.0
   720x400        70.1
HDMI-1 disconnected (normal left inverted right x axis y axis)

$ cat /proc/cmdline
ro root=UUID=91e7d1a8-7208-491c-ba3e-47ec918f66d6 rd_NO_LUKS rd_NO_LVM
rd_NO_MD rd_NO_DM LANG=en_US.UTF-8 SYSFONT=latarcyrheb-sun16
KEYTABLE=us rhgb quiet elevator=deadline

$ lsmod|grep nouve
nouveau               525018  2
ttm                    55120  1 nouveau
drm_kms_helper         27515  1 nouveau
drm                   187984  4 nouveau,ttm,drm_kms_helper
i2c_algo_bit            5014  1 nouveau
i2c_core               25468  6
i2c_i801,videodev,nouveau,drm_kms_helper,drm,i2c_algo_bit
video                  12432  1 nouveau

$ lsmod|grep nvi
$

Any hint on using gnome 3 standard or otherwise to have fallback mode
to work as a full gnome 2.x?
Thanks in advance,
Gianluca