The SMS Mirror Driver

The SMS Mirror driver is the root cause of the problem, with help from a dated video driver, the SMS Remote Control application (Wuser32.exe), and an unsupported operating system (Windows 2000).

So what does the SMS Mirror Driver do?:

Video acceleration significantly speeds up your Remote Control sessions clients.  For video acceleration on clients running Windows 2000 or later, SMS uses a Mirror driver.  The Mirror driver can simultaneously display the same output to several video devices and has no dependencies on the client’s video driver.
– Microsoft Systems Management Server 2003 Operations Guide.

We received a fault report:

My desktop icons are grey colored.

It took some investigation, as the customer left out some details.  Here they are:

  • the problem was occurring on a system they were remote controlling with the SMS Remote Control application.
  • it was an intermittent problem.
  • it was in a development environment.

The cause?
As we’re not able to call Microsoft about the issue (unsupported operating system), this is what I think was happening:

Starts Remote Controlling    Finishes Remote Controlling
.-------------------.        .--------------------.
|    User starts     |       | Customer finishes  |
| Remote Controlling |       | Remote Controlling |
|       of PC        |       |      of PC         |
`--------------------'       `--------------------'
          |                            |
          |                            |
.--------------------.       .--------------------.
|  SMS Mirror Driver  |      | SMS Mirror Driver  |
|(sets 256 color mode)|      |(trys to reset to   |
|                     |      |  65535 colors)     |
`---------------------'      `--------------------'
          |                            |
          |                            |
.--------------------.       .--------------------.
|                     |      |Display Driver fails|
|    Display Driver   |      | to reset to 65535  |
|                     |      |      colours       |
`---------------------'      `--------------------'

Solutions?

Answer 1:
Nothing we can do, as the operating system and the particular video driver is out of support.
As the issue is only occurring in a development environment, we’ve unable to investigate further.

Answer 2:
It may be possible disable the video acceleration feature of the SMS driver by either:
i. disabling the SMS Mirror driver by disabling the SMS Mirror service.
ii. disabling it globally via the SMS Administrator console.

Answer 2(b):
No, we do not recommend it, as it will cause adverse network issues.

What about other display mirror drivers?
The CA Unicentre Remote Control product prior to version 6.0 did not support multiple monitors.  At version 6, they implemented a mirror driver.
The Microsoft Netmeeting product also uses a mirror driver.
You can read more about mirror drivers here and here.

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