usb-c ports Titan Ridge capped at 480 Mb/s

usb-c ports (4) are limited to 480 Mb/s. Should be 10 Gb/s
any device selecting a higher speed is ignored, no output to **dmesg --human --follow**
(bus usb4…6)
hardware is Intel Corporation JHL7540 Thunderbolt 3 USB Controller [Titan Ridge 4C 2018] [8086:15ec] (rev 06)

usb-a ports (2) work at 5 Gb/s
(bus usb1…2)

Hardware is Mac mini (2018) Macmini8,1
Linux is linux-generic-hwe-20.04
uname --release
5.8.0-36-generic

usb bus speeds:
for A in /sys/bus/usb/devices/usb*; do echo "$(basename $A): $(< $A/speed)"; done
usb1: 480
usb2: 10000
usb3: 480
usb4: 10000
usb5: 480
usb6: 10000

usb controllers:
find /sys/devices -regextype egrep -regex '.*/usb[0-9]+'
/sys/devices/pci0000:00/0000:00:01.2/0000:7b:00.0/0000:7c:02.0/0000:7e:00.0/usb5
/sys/devices/pci0000:00/0000:00:01.2/0000:7b:00.0/0000:7c:02.0/0000:7e:00.0/usb6
/sys/devices/pci0000:00/0000:00:01.1/0000:05:00.0/0000:06:02.0/0000:08:00.0/usb3
/sys/devices/pci0000:00/0000:00:01.1/0000:05:00.0/0000:06:02.0/0000:08:00.0/usb4
/sys/devices/pci0000:00/0000:00:14.0/usb1
/sys/devices/pci0000:00/0000:00:14.0/usb2

usb controller modules and drivers:
lspci -knns14
00:14.0 USB controller [0c03]: Intel Corporation Cannon Lake PCH USB 3.1 xHCI Host Controller [8086:a36d] (rev 10)
    Subsystem: Intel Corporation Cannon Lake PCH USB 3.1 xHCI Host Controller [8086:7270]
    Kernel driver in use: xhci_hcd
    Kernel modules: xhci_pci
lspci -knns7e:0
7e:00.0 USB controller [0c03]: Intel Corporation JHL7540 Thunderbolt 3 USB Controller [Titan Ridge 4C 2018] [8086:15ec] (rev 06)
    Subsystem: Intel Corporation JHL7540 Thunderbolt 3 USB Controller [Titan Ridge 4C 2018] [8086:0000]
    Kernel driver in use: xhci_hcd
    Kernel modules: xhci_pci
lspci -knns8:0
08:00.0 USB controller [0c03]: Intel Corporation JHL7540 Thunderbolt 3 USB Controller [Titan Ridge 4C 2018] [8086:15ec] (rev 06)
    Subsystem: Intel Corporation JHL7540 Thunderbolt 3 USB Controller [Titan Ridge 4C 2018] [8086:0000]
    Kernel driver in use: xhci_hcd
    Kernel modules: xhci_pci ​

**lsb_release -rd**
Description: Ubuntu 20.04.2 LTS
Release: 20.04
---
ProblemType: Bug
ApportVersion: 2.20.11-0ubuntu27.16
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: gdm 1470 F.... pulseaudio
CasperMD5CheckResult: skip
DistroRelease: Ubuntu 20.04
InstallationDate: Installed on 2020-09-20 (138 days ago)
InstallationMedia: Ubuntu 20.04.1 LTS "Focal Fossa" - Release amd64 (20200731)
MachineType: Apple Inc. Macmini8,1
Package: linux (not installed)
ProcEnviron:
 TERM=screen
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
ProcFB: 0 i915drmfb
ProcKernelCmdLine: root=/dev/mapper/hostname-rfs ro initrd=\initrd.img-5.8.0-36-generic
ProcVersionSignature: Ubuntu 5.8.0-36.40~20.04.1-generic 5.8.18
PulseList: Error: command ['pacmd', 'list'] failed with exit code 1: No PulseAudio daemon running, or not running as session daemon.
RelatedPackageVersions:
 linux-restricted-modules-5.8.0-36-generic N/A
 linux-backports-modules-5.8.0-36-generic N/A
 linux-firmware 1.187.9
Tags: focal
Uname: Linux 5.8.0-36-generic x86_64
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: N/A
_MarkForUpload: True
dmi.bios.date: 07/12/2020
dmi.bios.release: 0.1
dmi.bios.vendor: Apple Inc.
dmi.bios.version: 1037.147.4.0.0 (iBridge: 17.16.16610.0.0,0)
dmi.board.name: Mac-7BA5B2DFE22DDD8C
dmi.board.vendor: Apple Inc.
dmi.board.version: Macmini8,1
dmi.chassis.type: 9
dmi.chassis.vendor: Apple Inc.
dmi.chassis.version: Mac-7BA5B2DFE22DDD8C
dmi.modalias: dmi:bvnAppleInc.:bvr1037.147.4.0.0(iBridge17.16.16610.0.0,0):bd07/12/2020:br0.1:svnAppleInc.:pnMacmini8,1:pvr1.0:rvnAppleInc.:rnMac-7BA5B2DFE22DDD8C:rvrMacmini8,1:cvnAppleInc.:ct9:cvrMac-7BA5B2DFE22DDD8C:
dmi.product.family: Mac mini
dmi.product.name: Macmini8,1
dmi.product.version: 1.0
dmi.sys.vendor: Apple Inc.