Duplicate indicators bar and desktops with overlapped screens

[Sebastien Bacher]

Using 4.22 in Oneiric with a dell laptop docked lid closed and with the internal screen enabled and placed "under" the external one in the xrandr capplet (dunno how that happened but it's the config I got on lid close and I can reproduce it manually by dnding the monitor and then enabling it), the indicators are duplicated

[Test Case - xrandr]
1. With a laptop and external monitor of dissimilar maximum resolutions
2. Set to extended (left/right or above/below) and each display at maximum resolution
3. xrandr --output LVDS1 --off
4. xrandr --output LVDS1 --auto
Is: Both displays show the same workspace as if mirrored, except the external display shows an extra main bar and background, at the laptop's resolution.
Should be: Both displays shown extended as configured in step #2.

[Test Case - gnome-display-properties]
1. With a laptop and external monitor of dissimilar maximum resolutions
2. Launch gnome-display-properties (from Unity apps scope search for "screens")
3. Set to extended (left/right or above/below) and each display at maximum resolution
4. Disable the laptop screen; Apply
5. Drag the disabled laptop screen to overlay the enabled external screen in the config tool
6. Enable the laptop screen
Is: Both displays show the same workspace as if mirrored, except the external display shows an extra main bar and background, at the laptop's resolution.
Should be: Both displays shown extended as configured in step #3.

[Sebastien Bacher (seb128)]

xrandr log:

$ xrandr

Screen 0: minimum 320 x 200, current 1920 x 1080, maximum 8192 x 8192
eDP1 connected 1440x900+93+0 (normal left inverted right x axis y axis) 304mm x 190mm
   1440x900 60.0*+ 40.0
VGA1 disconnected (normal left inverted right x axis y axis)
HDMI1 connected 1920x1080+0+0 (normal left inverted right x axis y axis) 521mm x 293mm
   1920x1080 60.0*+
   1600x1200 60.0
   1680x1050 60.0
   1280x1024 75.0 60.0
   1440x900 75.0 59.9
   1152x864 75.0
   1280x720 60.0
   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
DP1 disconnected (normal left inverted right x axis y axis)
HDMI2 disconnected (normal left inverted right x axis y axis)
DP2 disconnected (normal left inverted right x axis y axis)
  1440x900 (0xc6) 86.5MHz
        h: width 1440 start 1488 end 1520 total 1568 skew 0 clock 55.2KHz
        v: height 900 start 903 end 909 total 920 clock 60.0Hz

[Sebastien Bacher (seb128)]

Sync() call from d-feet

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[Sebastien Bacher (seb128)]

the screenshot of the bug

[Marco Trevisan (Treviño) (3v1n0)]

I guess that this is not only related to unity but this seems to affect other parts too..

However, is it just me (I'm testing this on VirtualBox, so maybe this is not so accurate) or also nautilus desktop is duplicated?
See the attached screenshot.

The indicators seems to be there just because they "think" to be on the other screen. And what is shown in your smaller screen?

[Sebastien Bacher (seb128)]

it could be a buggy xrandr setup and not a bug yes, in my case that happened when closing the lid of my docked laptop so there is a bug in g-s-d or xorg that it landed in that config, I can't say what is on the small screen since the lid is closed ;-)

[Sebastien Bacher (seb128)]

doing an "also affect xorg-server", not sure the monitors should be allow to overlap this way, for the record the first time it happened the configuration came on a lid close not from a manual change, it could be a g-s-d bug as well

[Bryce Harrington (bryce)]

I've reproduced this on my hardware as well, in certain dual-head configurations, running the command:
xrandr --output VGA1 --auto --output LVDS1 --auto

I strongly suspect it is a window manager bug but will leave the X task open until that's more certain.

[Bryce Harrington (bryce)]

Was able to reproduce on Precise with a laptop and ext display with docking station, using seb128's steps.

[Bryce Harrington (bryce)]

Allowing two displays to overlap and show different sized viewports of the same desktop is totally permissible by X11 with RANDR. I can't think of any particular use case where you'd *want* it set up that way, but technically it is a permissible configuration as far as X is concerned. It is more of a question of policy.

While I think I can reproduce it under some circumstances with xrandr, I'm not sure that means we should implement the policy at the X level, or if it just means we have two config tools that need the same fix.

[Bryce Harrington (bryce)]

Photo showing what this configuration problem looks like.

[Marco Trevisan (Treviño) (3v1n0)]

FYI I've not worked on this until now since the problem is not only on the panel, but also on nautilus.
So we should define how to solve this, as this is just a special "mirror" case.

[Bryce Harrington (bryce)]

Right, nautilus appears to have gotten confused here.

I *think* there's nothing we need to alter on the X side, so will close out the X task.

[Bryce Harrington (bryce)]

Still able to reproduce this with current unity 5.2 (although I still think it's a nautilus bug, really.)

[Marco Trevisan (Treviño) (3v1n0)]

Mh, actually the problem is related to both.... Unity should better handle the case in which we have overlapping monitors showing only a panel.
However imho the system should avoid that this situation would happen.

[Sebastien Bacher (seb128)]

The desktop view has been deprecated from nautilus, closing