ax88179_178a: Link state changes cause USB hiccups

[rojer]

Bus 003 Device 061: ID 0b95:1790 ASIX Electronics Corp. AX88179 Gigabit Ethernet

Link changes on this device cause approx. 5 second hiccups on the USB bus - keyboard and mouse become unresponsive.

Here's my USB device tree:

[rojer@nbd ~]$ lsusb -t
/: Bus 04.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/6p, 10000M
/: Bus 03.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/12p, 480M
    |__ Port 5: Dev 2, If 0, Class=Vendor Specific Class, Driver=, 12M
    |__ Port 8: Dev 55, If 0, Class=Hub, Driver=hub/5p, 480M
        |__ Port 1: Dev 61, If 0, Class=Vendor Specific Class, Driver=ax88179_178a, 480M <===
        |__ Port 3: Dev 58, If 0, Class=Hub, Driver=hub/7p, 480M
        |__ Port 5: Dev 60, If 0, Class=, Driver=, 480M
    |__ Port 9: Dev 48, If 0, Class=Hub, Driver=hub/6p, 480M
        |__ Port 5: Dev 51, If 0, Class=Human Interface Device, Driver=usbhid, 480M
        |__ Port 3: Dev 52, If 4, Class=Human Interface Device, Driver=usbhid, 480M
        |__ Port 3: Dev 52, If 2, Class=Audio, Driver=snd-usb-audio, 480M
        |__ Port 3: Dev 52, If 0, Class=Video, Driver=uvcvideo, 480M
        |__ Port 3: Dev 52, If 3, Class=Audio, Driver=snd-usb-audio, 480M
        |__ Port 3: Dev 52, If 1, Class=Video, Driver=uvcvideo, 480M
        |__ Port 4: Dev 50, If 0, Class=Human Interface Device, Driver=usbhid, 1.5M
        |__ Port 2: Dev 49, If 0, Class=Human Interface Device, Driver=usbhid, 1.5M <===
    |__ Port 10: Dev 5, If 0, Class=Wireless, Driver=btusb, 12M
    |__ Port 10: Dev 5, If 1, Class=Wireless, Driver=btusb, 12M
/: Bus 02.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/4p, 10000M
/: Bus 01.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/1p, 480M

Ethernet adapter and keyboard marked by "<===", they only share root hub.

To reproduce - replug the the cable or force link renegotiation with "sudo ethtool -s enxa0cec8fb9be3 autoneg on", observe hiccup wiht KB and mouse unresponsive.

AX driver is to blame because this does not happen with other USB-eth adapters, e.g. r8152, even when plugged into the same hub as ax88179:

        |__ Port 1: Dev 61, If 0, Class=Vendor Specific Class, Driver=ax88179_178a, 480M
        |__ Port 2: Dev 62, If 0, Class=Hub, Driver=hub/2p, 480M
            |__ Port 1: Dev 63, If 0, Class=Vendor Specific Class, Driver=r8152, 480M

Link changes on r8152 do not cause hiccups.

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: linux-image-5.13.0-25-generic 5.13.0-25.26~20.04.1
ProcVersionSignature: Ubuntu 5.13.0-25.26~20.04.1-generic 5.13.19
Uname: Linux 5.13.0-25-generic x86_64
NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair
ApportVersion: 2.20.11-0ubuntu27.21
Architecture: amd64
CasperMD5CheckResult: skip
CurrentDesktop: ubuntu:GNOME
Date: Tue Jan 18 22:13:35 2022
InstallationDate: Installed on 2020-04-01 (657 days ago)
InstallationMedia: Ubuntu 20.04 LTS "Focal Fossa" - Alpha amd64 (20200315)
SourcePackage: linux-signed-hwe-5.13
UpgradeStatus: No upgrade log present (probably fresh install)