ubuntu-x-swat team mailing list archive

[Rudolf Cardinal <316514@xxxxxxxxxxxxxxxxxx>]

I hope this is the right bug to add to; apologies if not.

My problem is: Xorg 1.9 can't do a single seamless desktop with two
video cards without Xinerama.

I'm running Ubuntu 10.10 (Maverick) on a Asus P5N32-SLI motherboard with
two NVidia GeForce 7600GS video cards (these are NV40-class cards as
seen by Nouveau) through PCI. Each card is connected to a (rotatable)
monitor, as it happens via DVI. My sequence of problems has been:

1. Current binary NVidia drivers for Ubuntu 10.04 allowed (with
Xinerama) the left monitor to run in landscape mode and the right
monitor in portrait mode (using ' Option "Rotate" "CCW" ' in the Device
section of xorg.conf). However, they caused intermittent machine lockups
(variably but including nothing-working crashes, including keyboard LEDs
and kernel SysRq magic keys). Machine effectively unusable. So, out with
NVidia drivers (except that their removal left the machine unbootable,
so on to Ubuntu 10.10 and nouveau).

2. The Nouveau drivers reject Option "Rotate" ("(WW) NOUVEAU(1): Option
"Rotate" is not used" in /var/log/Xorg.0.log).

3. Xinerama allows a seamless desktop, though without the ability to
rotate one monitor. However, it crashes a bunch of apps at present; see
bug https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/650539 . So
Xinerama is (currently) out of the question, and, as I understand it, is
deprecated in any case.

4. Creating two {Device, Monitor, Screen} sets of descriptions in
xorg.conf, and stitching them together in the ServerLayout section
[Screen 0 "Screen0" 0 0 / Screen 1 "Screen1" RightOf "Screen0"], allows
two video cards with two monitors to be used. Great! And running "xrandr
--screen 1 --output DVI-I-2 --rotate left" from a new file
/etc/X11/Xsession.d/45custom-xrandr-settings allows the right-hand
(second) monitor to go into portrait mode automatically following first
login to X.

5. However, in this configuration there are two X screens, each with its
own taskbar, and windows can't be dragged between screens, although the
mouse pointer can wander between them. Presumably this reflects the
problem of "one pool of memory per graphics card" described above, as
other web sources suggest that a seamless desktop is easy to create on
"dualhead" or similar (>1 output from a single video card) systems.

6. So, upshot: Xinerama is deprecated and now makes things crash, but
X.org 1.9 with XRandR 1.3 doesn't seem able to create a seamless desktop
across two video cards.

-- 
MASTER:  Xinerama/Multihead with several video cards is not supported
https://bugs.launchpad.net/bugs/316514
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