Apparently a recent upgrade broke the dual-head display again.  I have two monitors (different sizes/resolutions), and at least for a while it seemed to be doing the right thing (two independent screens), but since playing a game full screen which 'turned off' the independence, I can't get the displays to be independent via the Settings|Display applet.  I can get the displays to seperate by using --left-of in xrandr, but on reboot, that settings is lost and the display are again mirrored.

Just did what you did at first? Because Xfce doesn't really do anything
to configure your displays, so all the configuration has to be done in
xorg (or using xrandr).

And I have to admit I'm puzzled by what you mean by “independance”,
would you mind explaining it a bit more?

Regards,

On Tue, 21 Jun 2011 20:31:33 +0200 Yves-Alexis Perez <corsac@debian.org> wrote:

Actually since 4.6 (or 4.4) the 'Display' settings applet has taken over
doing the xrandr stuff.  However at that point there
was /etc/.config/xfce/monitor.xml which and a <clone> tag which could
be <clone>no</clone> (or off, can't remember), which would result in
the two monitors being separate (without that the smallest monitor is
mirrored on the larger monitor, so you effectively have one monitor,
just displayed twice).  Unfortunately in the 4.8 the clone option was
removed and I don't know how to tell xfce to not mirror the displays
(mirroring is the default, unless you use xrandr to tell it not to
mirror).  Also, the Display applet settings are now applied after the
/etc/.config/autostart stuff, so it doesn't work to do what I used to
do, which is have and xrandr script in autostart.

Basically 4.6 was doing the right thing, and it's broken now because
there is no way to not mirror automatically (though once initialization
is complete I can manually do xrandr and separate the outputs so they
are different displays (independent) rather than mirrored (the default).

Regards,

Daniel

Oh, you have xfce4-display-settings --minimal, which is aliased by
default to XF86Display and Super-P

Regards,

On Sun, 03 Jul 2011 18:53:19 +0200 Yves-Alexis Perez <corsac@debian.org> wrote:

Oh, that appears to be for setting manually.  I can already do that
with xrandr --output DVI-0 --left-of DisplayPort-0

I'm looking for a) at least being able to set this on boot (as I
mentioned this is no longer possible, because the display settings get
modified by xfce-display-settings or somesuch after the startup stuff
in ~/.config/autostart
b) eventually to have xfce4-display-settings correctly handle two
non-mirrored monitors at the same time.  --minimal only lets you turn
on or off one display at a time, or clone, not to have two different
displays at the same time (the X kind with xrandr where dual head is
the same desktop just two different viewports/outputs).  Same problem
with the non-minimal version.

Regards,

Daniel

Then you want to drop something in /etc/X11/xorg.conf.d/ or just cook an
xrandr script.

Yeah, maybe something like that will be in 4.10, but for now you want
xrandr (or any frontend) or xorg.conf.d.

Regards,

This has been fixed upstream, if it's not in 4.10 (testing, unstable)
it should be fixed in 4.11 (experimental). Could you try one of them?