Ok I have found the trigger for the usb error on my system. I did not have to insert/remove any device as such, but simply put the laptop into suspend mode. At the moment it resumes from suspend, the error can be consistently reproduced on both signed and testing kernels.
There are a number of other internal devices on the USB hub, such as WebCam SC-10HDP12631N, and ELAN Touchscreen. See my attached kern.log for full usb and suspend output. Aug 14 18:05:57 730U3E kernel: [ 95.978282] usb 1-1.5: reset full-speed USB device number 4 using ehci-pci Aug 14 18:05:57 730U3E kernel: [ 95.978287] usb 2-1.5: reset full-speed USB device number 3 using ehci-pci Aug 14 18:05:57 730U3E kernel: [ 95.978520] usb 3-3: reset high-speed USB device number 2 using xhci_hcd Aug 14 18:05:57 730U3E kernel: [ 96.166202] usb 1-1.4: reset high-speed USB device number 3 using ehci-pci Aug 14 18:06:01 730U3E kernel: [ 100.429382] usb usb4-port2: Cannot enable. Maybe the USB cable is bad? Aug 14 18:06:05 730U3E kernel: [ 104.520742] usb usb4-port2: Cannot enable. Maybe the USB cable is bad? Aug 14 18:06:10 730U3E kernel: [ 108.592236] usb usb4-port2: Cannot enable. Maybe the USB cable is bad? ** Attachment added: "kern.log.txt" https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1856608/+attachment/5401562/+files/kern.log.txt -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1856608 Title: [Regression] usb usb2-port2: Cannot enable. Maybe the USB cable is bad? Status in linux package in Ubuntu: Incomplete Status in linux source package in Bionic: Fix Released Status in linux source package in Disco: Fix Released Status in linux source package in Eoan: Fix Released Status in linux source package in Focal: Incomplete Bug description: This appears to be a regression between 4.15.0-70.79 and 4.15.0-72.81. This bug was fixed by simply reverting the offending change. Bug 1859873 tracks root causing the issue and reapplying the change w/ any necessary fixes. [Impact] USB port unusable and boot time takes ~5 minutes longer to complete. Kernel emits messages like: usb usb2-port2: Cannot enable. Maybe the USB cable is bad? [Test Case] dmesg | grep "Cannot enable" [Fix] [Regression Risk] To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1856608/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
