New: AMD Strix Halo (ASUS GZ302EA): TB4 dock's USB 2.0 upstream never enumerates on xHCI companion port — "Cannot enable" x4, power cycle, gives up; USB4 link and USB3 tunnel work
https://bugzilla.kernel.org/show_bug.cgi?id=221785
Bug ID: 221785
Summary: AMD Strix Halo (ASUS GZ302EA): TB4 dock's USB 2.0
upstream never enumerates on xHCI companion port — "Cannot enable" x4, power cycle, gives up; USB4 link and USB3 tunnel work
Product: Drivers
Version: 2.5
Kernel Version: 7.0.0-14-generic
Hardware: AMD
OS: Linux
Status: NEW
Severity: normal
Priority: P3
Component: USB
Assignee: [email protected]
Reporter: [email protected]
Regression: No
One defect, consistently reproducible: a Thunderbolt 4 dock's USB 2.0 hub upstream fails to enumerate on this AMD USB4 host's USB 2.0 companion port. Everything else about the link is healthy.
Hardware:
- Host: ASUS ROG Flow Z13 GZ302EA — AMD Ryzen AI Max+ 395 w/ Radeon 8060S ("Strix Halo"), two USB4 ports.
BIOS GZ302EA.311 (latest), ASUS PD firmware updated (ROG PD Firmware Update tool V2.13.0.001).
- Dock: Sonnet Echo 20 Thunderbolt 4 SuperDock (ECHO-DK20-T4, Goshen Ridge), included TB4 cable, own power supply.
- Kernel: 7.0.0-14-generic (Ubuntu live session).
Observed (all captures attached, taken in the same session):
1. USB4 side is fully functional. The CM enumerates the dock router and both Parade PS8833 retimers, and bolt authorizes it at 40 Gb/s x2 lanes each direction:
[ 4673.092478] thunderbolt 1-2: new device found, vendor=0x8 device=0x68 [ 4673.092485] thunderbolt 1-2: Sonnet Echo 20 Thunderbolt 4 SuperDock [ 4673.820989] thunderbolt 1-0:2.1: new retimer found, vendor=0x1da0 device=0x8833 [ 4674.652993] thunderbolt 1-2:1.1: new retimer found, vendor=0x1da0
device=0x8833
The tunneled USB3 side comes up and works (dock hub chain and Realtek r8152 2.5GbE on bus 8, lsusb-t.txt).
2. The dock's USB 2.0 upstream fails on the companion port of the same connector, in parallel with the successful USB4 bring-up:
[ 4674.354967] usb usb7-port1: Cannot enable. Maybe the USB cable is bad? [ 4675.242360] usb usb7-port1: Cannot enable. Maybe the USB cable is bad? [ 4675.242627] usb usb7-port1: attempt power cycle [ 4676.258334] usb usb7-port1: Cannot enable. Maybe the USB cable is bad? [ 4677.146602] usb usb7-port1: Cannot enable. Maybe the USB cable is bad? [ 4677.147009] usb usb7-port1: unable to enumerate USB device
A connect is detected (D+ pull-up present) but the port never reaches enabled state after reset. Every USB 2.0 / FS / LS function of the dock is therefore dead (wireless receivers, dock audio, card reader).
3. The failure is invariant. The attached dmesg contains multiple plug cycles (four SuperSpeed connects of the dock's 8087:0b40 hub, five USB 2.0 enumeration-failure sequences) across BOTH physical USB4 ports and both link outcomes
(USB4 established, and USB 3.2 fallback sessions where mode entry did not occur): the USB 2.0 failure signature is byte-for-byte identical every time (usb5-port1 at ~648s/777s, usb7-port1 at ~4674s). Link mode and port are not variables.
A "ucsi_acpi USBC000:00: GET_CURRENT_CAM command failed" follows each dock connect (platform PPM errors on the alt-mode query).
Cross-checks already performed:
- Windows 11 on the same machine: identical end state — the xHCI companion port (USB Device Tree Viewer, PortConnectorIsTypeC, CompanionPortChain) reports ConnectionStatus 0x00 while the USB3 side works. So this is OS-independent.
- macOS (Apple Silicon), same dock + same cable + same devices:
full USB 2.0 tree (three hub levels) enumerates and works. The dock and the cable's D+/D- pair are fine.
- A native USB 3.2 dock (Belkin, no USB4 layer) on the same physical connector enumerates BOTH its USB 3.x and USB 2.0 sides. The host's USB 2.0 companion path is fine with other devices.
- Vendor cases open: Sonnet support case #00021656 — Sonnet has confirmed reproducing an AMD USB4 host enumeration issue with newer TB4/TB5 peripherals in their own lab and is contacting AMD/Intel/Microsoft; ASUS escalation N2607023142 (BIOS-level fix requested).
Why this report: given the cross-OS reproduction this is most likely a platform/electrical-level interop defect rather than a kernel regression. Filing so the AMD USB4/platform maintainers are aware and the vendor cases can be linked, and to ask whether a kernel-side mitigation is feasible (e.g. xhci reset/retry tuning or a quirk for this pairing). Happy to run any instrumented builds, capture thunderbolt/xhci dynamic debug, or test patches — the machine and dock are available.
Attachments: kernel-version.txt, dmesg-boot.txt (full boot plus all plug cycles), lsusb-t.txt, lsusb-v.txt, lspci.txt, tb-devices.txt, boltctl.txt.
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[Bug 221785] AMD Strix Halo (ASUS GZ302EA): TB4 dock's USB 2.0 upstream never enumerates on xHCI companion port — "Cannot enable" x4, power cycle, gives up; USB4 link and USB3 tunnel work
https://bugzilla.kernel.org/show_bug.cgi?id=221785
--- Comment #1 from [email protected] ---
Created attachment 310500
--> https://bugzilla.kernel.org/attachment.cgi?id=310500&action=edit
uname -a
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[Bug 221785] AMD Strix Halo (ASUS GZ302EA): TB4 dock's USB 2.0 upstream never enumerates on xHCI companion port — "Cannot enable" x4, power cycle, gives up; USB4 link and USB3 tunnel work
In reply to [email protected]https://bugzilla.kernel.org/show_bug.cgi?id=221785
--- Comment #2 from [email protected] ---
Created attachment 310501
--> https://bugzilla.kernel.org/attachment.cgi?id=310501&action=edit
boltctl list — dock authorized, USB4 40G x2
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[Bug 221785] AMD Strix Halo (ASUS GZ302EA): TB4 dock's USB 2.0 upstream never enumerates on xHCI companion port — "Cannot enable" x4, power cycle, gives up; USB4 link and USB3 tunnel work
In reply to [email protected]https://bugzilla.kernel.org/show_bug.cgi?id=221785
--- Comment #3 from [email protected] ---
Created attachment 310502
--> https://bugzilla.kernel.org/attachment.cgi?id=310502&action=edit
dmesg — full boot + all plug cycles
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[Bug 221785] AMD Strix Halo (ASUS GZ302EA): TB4 dock's USB 2.0 upstream never enumerates on xHCI companion port — "Cannot enable" x4, power cycle, gives up; USB4 link and USB3 tunnel work
In reply to [email protected]https://bugzilla.kernel.org/show_bug.cgi?id=221785
--- Comment #4 from [email protected] ---
Created attachment 310503
--> https://bugzilla.kernel.org/attachment.cgi?id=310503&action=edit
lsusb -t — USB4-entered state, companion bus empty
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[Bug 221785] AMD Strix Halo (ASUS GZ302EA): TB4 dock's USB 2.0 upstream never enumerates on xHCI companion port — "Cannot enable" x4, power cycle, gives up; USB4 link and USB3 tunnel work
In reply to [email protected]https://bugzilla.kernel.org/show_bug.cgi?id=221785
--- Comment #5 from [email protected] ---
Created attachment 310504
--> https://bugzilla.kernel.org/attachment.cgi?id=310504&action=edit
lsusb -v
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[Bug 221785] AMD Strix Halo (ASUS GZ302EA): TB4 dock's USB 2.0 upstream never enumerates on xHCI companion port — "Cannot enable" x4, power cycle, gives up; USB4 link and USB3 tunnel work
In reply to [email protected]https://bugzilla.kernel.org/show_bug.cgi?id=221785
--- Comment #6 from [email protected] ---
Created attachment 310505
--> https://bugzilla.kernel.org/attachment.cgi?id=310505&action=edit
lspci -vvnn
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[Bug 221785] AMD Strix Halo (ASUS GZ302EA): TB4 dock's USB 2.0 upstream never enumerates on xHCI companion port — "Cannot enable" x4, power cycle, gives up; USB4 link and USB3 tunnel work
In reply to [email protected]https://bugzilla.kernel.org/show_bug.cgi?id=221785
--- Comment #7 from [email protected] ---
Created attachment 310506
--> https://bugzilla.kernel.org/attachment.cgi?id=310506&action=edit/sys/bus/thunderbolt/devices listing
Signature · 4 lines
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[Bug 221785] AMD Strix Halo (ASUS GZ302EA): TB4 dock's USB 2.0 upstream never enumerates on xHCI companion port — "Cannot enable" x4, power cycle, gives up; USB4 link and USB3 tunnel work
In reply to [email protected]https://bugzilla.kernel.org/show_bug.cgi?id=221785
--- Comment #8 from Artem S. Tashkinov ([email protected]) --- Is this reproducible in 7.1.5?
7.0.x is EOL.
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[Bug 221785] AMD Strix Halo (ASUS GZ302EA): TB4 dock's USB 2.0 upstream never enumerates on xHCI companion port — "Cannot enable" x4, power cycle, gives up; USB4 link and USB3 tunnel work
In reply to [email protected]https://bugzilla.kernel.org/show_bug.cgi?id=221785
--- Comment #9 from [email protected] ---
Created attachment 310510
--> https://bugzilla.kernel.org/attachment.cgi?id=310510&action=edit
dmesg, kernel 7.1.5, USB4-entered state (reproduction)
Reproduced on 7.1.5 (Linux work 7.1.5-070105-generic #202607241434 SMP PREEMPT_DYNAMIC Fri Jul 24 14:57:06 UTC 2026 x86_64): identical signature — "Cannot enable" x4, attempt power cycle, unable to enumerate on the xHCI companion port (usb5-port1), occurring in parallel with successful USB4 bring-up (Sonnet Echo 20 router and both retimers enumerated, this time on the other domain/port). Fresh dmesg attached.
(Note: the usb-storage.quirks / rootdelay entries on the kernel cmdline relate to an unrelated NS1081 USB enclosure used as the boot disk, not the dock.)
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