Enabling Xinerama causes Unity Panel/Dash to become all black

[Chris J Arges]

Description:

When running 2 Nvidia video cards Xinerama is needed to seamlessly span all screens. When Xinerama is enabled this causes the panel to turn black and the 'dash' start flickering. Several screen shots are included

Steps to reproduce:
    1) Install nvidia drivers (nvidia-current or nvidia-current-updates or drivers from Nvidia site)
    2) Run nvidia-settings and enable all monitors on video cards
    3) Enable xinerama using nvidia-settings
    4) Log out or reboot. Log in, click on dash and symptoms will start.

Note:
This couldn't be tested using the nouveu drivers due to it not properly handling full resolution on a single monitor.

Hardware:
Nvidia NVS 510

Version affected:
Precise

ii libxinerama1 2:1.1.1-3build1 X11 Xinerama extension library
ii unity 5.18.0-0ubuntu1 Interface designed for efficiency of space and interaction.
ii linux-image-generic 3.2.0.34.37 Generic Linux kernel image
ii nvidia-common 1:0.2.44.2 Find obsolete NVIDIA drivers
ii nvidia-current 295.40-0ubuntu1.1 NVIDIA binary Xorg driver, kernel module and VDPAU library
ii nvidia-settings 295.33-0ubuntu1 Tool of configuring the NVIDIA graphics driver

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Kevin Metz (pertinent)]

xdpyinfo:
name of display: :0
version number: 11.0
vendor string: The X.Org Foundation
vendor release number: 11103000
X.Org version: 1.11.3
maximum request size: 16777212 bytes
motion buffer size: 256
bitmap unit, bit order, padding: 32, LSBFirst, 32
image byte order: LSBFirst
number of supported pixmap formats: 7
supported pixmap formats:
    depth 1, bits_per_pixel 1, scanline_pad 32
    depth 4, bits_per_pixel 8, scanline_pad 32
    depth 8, bits_per_pixel 8, scanline_pad 32
    depth 15, bits_per_pixel 16, scanline_pad 32
    depth 16, bits_per_pixel 16, scanline_pad 32
    depth 24, bits_per_pixel 32, scanline_pad 32
    depth 32, bits_per_pixel 32, scanline_pad 32
keycode range: minimum 8, maximum 255
focus: window 0x3600005, revert to Parent
number of extensions: 25
    BIG-REQUESTS
    DAMAGE
    DPMS
    DRI2
    GLX
    Generic Event Extension
    MIT-SCREEN-SAVER
    MIT-SHM
    NV-CONTROL
    NV-GLX
    RECORD
    RENDER
    SECURITY
    SHAPE
    SYNC
    X-Resource
    XC-MISC
    XFIXES
    XFree86-DGA
    XFree86-VidModeExtension
    XINERAMA
    XInputExtension
    XKEYBOARD
    XTEST
    XVideo
default screen number: 0
number of screens: 1

screen #0:
  dimensions: 7680x1600 pixels (2294x473 millimeters)
  resolution: 85x86 dots per inch
  depths (7): 24, 1, 4, 8, 15, 16, 32
  root window id: 0x225
  depth of root window: 24 planes
  number of colormaps: minimum 1, maximum 1
  default colormap: 0x20
  default number of colormap cells: 256
  preallocated pixels: black 0, white 16777215
  options: backing-store NO, save-unders NO
  largest cursor: 256x256
  current input event mask: 0xfac033
    KeyPressMask KeyReleaseMask EnterWindowMask
    LeaveWindowMask KeymapStateMask ExposureMask
    StructureNotifyMask SubstructureNotifyMask SubstructureRedirectMask
    FocusChangeMask PropertyChangeMask ColormapChangeMask
  number of visuals: 56
  default visual id: 0x21
  visual:
    visual id: 0x21
    class: TrueColor
    depth: 24 planes
    available colormap entries: 256 per subfield
    red, green, blue masks: 0xff0000, 0xff00, 0xff
    significant bits in color specification: 8 bits
  visual:
    visual id: 0x22
    class: DirectColor
    depth: 24 planes
    available colormap entries: 256 per subfield
    red, green, blue masks: 0xff0000, 0xff00, 0xff
    significant bits in color specification: 8 bits
  visual:
    visual id: 0x23
    class: TrueColor
    depth: 24 planes
    available colormap entries: 256 per subfield
    red, green, blue masks: 0xff0000, 0xff00, 0xff
    significant bits in color specification: 8 bits
  visual:
    visual id: 0x24
    class: TrueColor
    depth: 24 planes
    available colormap entries: 256 per subfield
    red, green, blue masks: 0xff0000, 0xff00, 0xff
    significant bits in color specification: 8 bits
  visual:
    visual id: 0x25
    class: TrueColor
    depth: 24 planes
    available colormap entries: 256 per subfield
    red, green,...

[Sebastien Bacher (seb128)]

Thank you for your bug report, could you give details about the "Launcher.qml" patch you used?