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 Kernel Packages, which is subscribed to linux-intel-5.13 in Ubuntu. https://bugs.launchpad.net/bugs/1939638 Title: [regression] USB device is not detected during boot Status in HWE Next: New Status in linux package in Ubuntu: Fix Released Status in linux-intel package in Ubuntu: Confirmed Status in linux-intel-5.13 package in Ubuntu: Fix Released Status in linux source package in Focal: Fix Released Status in linux-intel source package in Focal: Confirmed Status in linux-intel-5.13 source package in Focal: Fix Released Status in linux source package in Hirsute: Fix Released Status in linux-intel source package in Hirsute: Invalid Status in linux-intel-5.13 source package in Hirsute: Invalid Bug description: [SRU Justification] [Impact] The USB devices (keyboard, storage...) are failed to be detected when connecting to the problematic root hubs which need longer PowerOn-to-PowerGood delay than it claims in the hub descriptor. It's caused by the upstream fix 90d28fb53d4a ("usb: core: reduce power-on-good delay time of root hub"). [Fix] Reverting the upstream fix until a formal fix been placed. [Test Case] 1. Plug the USB device to the ports of problematic root hub. 2. Power on the machine. 3. Check if the USB device can work or not after boot. [Regression Potential] Low. The longer delay is proven safe in old kernels. ========== Original Bug Description ========== [Summary] The USB devices (keyboard, storage...) are failed to be detected during boot after upgrade to UBUNTU focal kernel 5.4.0-78 and hirsute 5.11.0-26. However, they will be detected and working ok after re-plugging. The kernel output shows as down below during boot [ 39.350435] hub 1-0:1.0: USB hub found [ 39.398835] hub 1-0:1.0: 12 ports detected [ 39.622744] usb usb1-port3: couldn't allocate usb_device And when I plug out then plug in the same device, it shows [57210.794140] usb 1-3: new low-speed USB device number 4 using xhci_hcd [57210.951289] usb 1-3: New USB device found, idVendor=17ef, idProduct=6099, bcdDevice= 1.14 [57210.951293] usb 1-3: New USB device strings: Mfr=1, Product=2, SerialNumber=0 After doing kernel bisecting, we found the upstream commit https://github.com/torvalds/linux/commit/90d28fb53d4a51299ff324dede015d5cb11b88a2 makes the difference. It indicates that the delay for the root hub from power_on to power_good is not long enough. There was no problem if the delay is 100 ms. From the Hub Descriptor of the root hub, the value is 10 * 2 milliseconds. And the XHCI spec also says in section 5.4.8 """ The host is required to have power stable to the port within 20 milliseconds of the '0' to '1' transition of PP. If PPC = '1', software is responsible for waiting 20ms. """ The commit seems to follow the SPEC but could cause problems on some hubs. [Reproduce Steps] 1. Plug the USB device to the physical port #1 and #4 which belongs to high-speed hub. 2. Power on the machine. 3. Check if the USB device can work or not after boot. [Results] Expected: All usb devices connect to the hub should work OK. Actual: USB devices connects to high-speed hub can not be probed. [Additional Information] Kernel Version: focal 5.4.0-78 and hirsute 5.11.0-26 [Upstream bug] https://bugzilla.kernel.org/show_bug.cgi?id=214021 To manage notifications about this bug go to: https://bugs.launchpad.net/hwe-next/+bug/1939638/+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
