[itog][tgl-up3] DisplayPort not detected by SUT

[Summary]
Image: iotg-focal-desktop-20210813.img

SUT has an on-board DP port. Plugging in a DP cable does not cause Desktop to detect the display. Settings->Display only shows the internal display, not a second display.

The associated CDTS test also fails.

[Steps to reproduce]
Plug in a DP monitor.
Open Settings->Display

[Expected result]
Options should appear for the DP monitor, the screen should appear on the external monitor.

[Actual result]
Ubuntu does not recognize a monitor has been connected.

[Failure rate] 100%

[Additional information]
CID: 202109-29412
SKU:
system-manufacturer: Intel Corporation
system-product-name: Tiger Lake Client Platform
bios-version: TGLIFUI1.R00.3455.A02.2011240812
CPU: 11th Gen Intel(R) Core(TM) i5-1145GRE @ 2.60GHz (8x)
GPU: 00:02.0 VGA compatible controller [0300]: Intel Corporation Device [8086:9a49] (rev 01)
kernel-version: 5.11.0-1012-intel

[Stage]
Issue reported and logs collected right after it happened