Why this answer matters
A dock can partially work—such as USB devices working while video or charging fails—because USB data, DisplayPort and Power Delivery are separate capabilities negotiated through the same USB-C connector.
Requirements
What has to be true
- A USB-C/USB4 cable and dock that support the specific data, display and charging features needed.
- For direct DisplayPort displays, Dell notes that a USB-C to DisplayPort adapter can be used.
- For charging, use a compatible USB-C Power Delivery source sized for the system configuration and workload.
Verify it yourself
Use this test sequence
Change one variable at a time so you know which requirement made the difference.
- 1
Test the charger directly in each USB-C port before testing through a dock.
- 2
Test the external monitor directly or through a simple known-good adapter before adding a multi-function dock.
- 3
If USB accessories work but display does not, verify the dock/cable specifically supports DisplayPort video.
- 4
If display works but the laptop discharges under load, compare the dock's power-delivery rating with the laptop's charging requirement.
Limits
What this answer does not prove
- Dell warns against connecting both cables from certain dual-cable docking stations to both USB-C ports simultaneously because charging-circuit issues can occur.
- A 40 Gbps port does not guarantee that every attached cable, dock or peripheral runs at 40 Gbps.
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