Multiple monitors found on a workstation component

  • 3755776
  • 15-Nov-2006
  • 27-Apr-2012

Environment

Novell ZENworks Asset Management 3.3 - ZAM3.3
Novell ZENworks 7 Asset Management - ZAM7
Novell ZENworks TS.Census 3.2

Situation

When a scan is performed the collector is detecting multiple monitor components on a workstation.

Resolution

Each workstation reporting more than one monitor apparently has an issue within its registry; under XP the Collector gets an EDID block from the registry for each monitor - this EDID block is supposed to have been read directly from the monitor by Windows itself at bootup time, and should ONLY exist for a given monitor if the monitor is actually "live".
This supposes that there isn't any software installed on the machine that for some reason emulates additional monitors.
A diagnostic WIF (with collector trace dump) from one of the affected machines would help point out exactly what's going on, but probably won't help very much in coming up with a solution for it - the problem isn't in the collector, it's in the Windows registry on each of these machines. You will need to learn why the Windows registry (or more particularly Windows itself) thinks it has multiple monitors installed and correct the problem.
To demonstrate the situation, open Regedit (or Regedt32) and browse to the following registry key:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Enum\DISPLAY

Under that key there should be exactly one subkey for each monitor type (manufacter / model) installed at runtime. Under that subkey there will be one more subkey with a GUID name, and under the GUID key will be one "Control" key per physical monitor connected to the workstation at runtime. From here, without the diagnostic WIF and trace dump, it looks very much like each of the affected workstations has more than one of these subkeys somewhere... subkeys that really don't belong there. Example registry hive:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum\DISPLAY\SNY1890\5&241c7fd2&0&10000082&01&00\Control
If any of the subkeys beyond DISPLAY was duplicated, the machine would appear (to the collector) to have two identical monitors.

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