Monitor Experiences Intermittent Blanking when Connected to Dell Docking Stations

A monitor may experience intermittently going black (blanking) when connected to a Dell docking station using HDMI, USB Type-C, or DisplayPort (DP) output. This is not limited to Dell branded monitors. This issue may also be reported on third-party monitors.

There are several possible causes and solutions that you can try:

1. Check your cables. Confirm that your cables are properly connected and securely plugged in. Loose connections can cause intermittent blanking.
2. Outdated drivers can cause compatibility issues and intermittent blanking. Ensure you are on the latest graphics driver for the attached device and dock model.
3. Check the Drivers & Downloads page from the Support Site for the monitor model for any recent firmware updates.
4. If the external monitor continues to intermittently blank out for 3 to 4 seconds, this may be a result of Display Stream Compression (DSC) being enabled.

Updating the Dell Dock WD19 or Dell Thunderbolt Dock WD22TB4 to firmware version 01.00.36, 01.00.20 or later resolves the issue.

To download and install the firmware, go to:

• Support for Dell Dock WD19 Drivers & Downloads
• Support for Dell Thunderbolt Dock - WD22TB4 Drivers & Downloads

Once the firmware update is installed on the docking station, you can Manually Enable DSC Using the Registry Key. Alternatively, Dell will roll back the DSC change in a future update to the video driver, enabling DSC by default.

A video driver workaround was previously implemented. For more information about the limitations and changes from the driver workaround, reference Resolution Changes. Users may observe different resolution support after applying this workaround when connecting to certain docks. For more information about Display Stream Compression (DSC), reference What is Display Stream Compression?

Manually Enable DSC Using the Registry Key

Caution: If done incorrectly, modifying the Windows Registry can lead to data loss or operating system corruption. Dell Technologies recommends that you back up data before proceeding with any Windows Registry edit. It is also recommended that a full backup of the Windows Registry is made before starting the edit. See Windows registry information for advanced users for additional information.

• Location: [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4d36e968-e325-11ce-bfc1-08002be10318}\0000]
  • Registry entry to update: "DPMstDscDisable"=dword:00000000
• Location: [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4d36e968-e325-11ce-bfc1-08002be10318}\0001]
  • Registry entry to update: "DPMstDscDisable"=dword:00000000
• Location: [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4d36e968-e325-11ce-bfc1-08002be10318}\0002]
  • Registry entry to update: "DPMstDscDisable"=dword:00000000

Resolution Changes

If the video driver workaround was installed, you may see resolution options change on your external displays, depending on your configuration.

What is Display Stream Compression?

Display Stream Compression can reduce the bandwidth required to transmit high-resolution video signals by compressing the video signal to reduce the amount of data that must be transmitted without compromising the image quality.

When DSC is enabled, the compression ratio varies depending on the resolution and refresh rate of the video signal being transmitted. In general, higher resolutions and refresh rates require higher compression ratios to maintain the same level of image quality. As a result, enabling DSC can increase the maximum resolution and refresh rate that can be supported over a given bandwidth.

DSC can also have some drawbacks. For example, some monitors may not be fully compatible with DSC. This may cause display issues or blanking.