See the attached dmesg output. Here's the relevant line: [ 37.400119] usb usb1-port4: couldn't allocate usb_device
The lspci utility is not available on Ubuntu Core 20, but when I boot Ubuntu Desktop 20.04 LTS from a live USB drive it yields the following output on the affected machine: $ lspci -nn | grep -i USB 00:15.0 USB controller [0c03]: Intel Corporation Celeron N3350/Pentium N4200/Atom E3900 Series USB xHCI [8086:5aa8] (rev 0b) Some additional observations: 1. Very, very occasionally, the "couldn't allocate usb_device" line won't be present in dmesg output and in this case the affected USB device *will* work immediately after boot. So this does seem to be a race condition of some kind. 2. I ran a quick check just in case: this is still present on the latest pc-kernel Snap update from a couple of days ago on the 20/stable channel (5.4.0-107.121.1). 3. I can confirm that the unbind-bind operation posted by tgs-bonn above makes the affected USB devices appear on my system as well: $ echo '0000:00:15.0' | sudo tee /sys/bus/pci/drivers/xhci_hcd/unbind $ sleep 1 $ echo '0000:00:15.0' | sudo tee /sys/bus/pci/drivers/xhci_hcd/bind ** Attachment added: "dmesg output" https://bugs.launchpad.net/hwe-next/+bug/1939638/+attachment/5576184/+files/dmesg.log -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1939638 Title: [regression] USB device is not detected during boot To manage notifications about this bug go to: https://bugs.launchpad.net/hwe-next/+bug/1939638/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
