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:
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:
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?
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4d36e968-e325-11ce-bfc1-08002be10318}\0000]
"DPMstDscDisable"=dword:00000000
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4d36e968-e325-11ce-bfc1-08002be10318}\0001]
"DPMstDscDisable"=dword:00000000
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4d36e968-e325-11ce-bfc1-08002be10318}\0002]
"DPMstDscDisable"=dword:00000000
If the video driver workaround was installed, you may see resolution options change on your external displays, depending on your configuration.
Condition | Triple Display | Quad Display (Daisy chain from DP) |
---|---|---|
HBR3 with DSC ON | DP+DP+MFDP/HDMI: 3*QHD (2560*1440 at 60 Hz) | DP+DP+HDMI/MFDP: 3*QHD at 60 Hz+1*1280*720 at 60 Hz |
HBR3 with DSC off (12.9 Gbps) | DP+DP+MFDP/HDMI: 3*FHD (1290*1080 at 60 Hz) | DP+DP+HDMI/MFDP: 4*1280*1024 at 60 Hz |
Condition | Triple Display | Quad Display (Daisy chain from DP) |
---|---|---|
HBR3 with DSC ON | DP+DP+MFDP/HDMI: 3*4k60Hz DP+DP/HDMI/MFDP+TBT: 2*4k 60 Hz+1*QHD 60 Hz |
DP+DP+HDMI/MFDP+TBT: 3*4k60Hz+1*4k30Hz/1*QHD60Hz |
HBR3 with DSC off (32.4 Gbps) | DP+DP+MFDP/HDMI: 1*4k60Hz+2*QHD60Hz DP+DP/HDMI/MFDP+TBT: 2*4k60Hz+1*QHD60Hz |
DP+DP+HDMI/MFDP+TBT: 4*QHD60Hz |
Condition | Single Display | Dual Display | Triple Display | Quad Display (Daisy chain from DP) |
---|---|---|---|---|
HBR3 with DSC ON | DP:8K (7680x4320) at 60 Hz HDMI:4k60Hz or 4k120Hz or 8k30Hz | HDMI+DP: 2*rk60Hz | HDMI+DP&DP (daisy chain): 3*QHD60Hz | HDMI+DP&DP&DP (daisy chain): 4*QHD60Hz |
HBR3 with DSC off (32.4 Gbps) | DP:4k30Hz | HDMI+DP 2*QHD60Hz | HDMI+DP&DP (daisy chain): FHD60Hz+2*1280x720@60Hz | HDMI+DP&DP&DP (daisy chain): FHD60Hz+3*1280x720@60Hz |
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.