[qubes-users] sys-usb problem: Unable to reset PCI device

Dear qubes users, I suddenly experience the following problem: sys-usb
won't start any more. It ran smoothly on debain-10/11-minimal for years.
It says

Start failed: internal error: Unable to reset PCI device 0000:00:14.0:
internal error: libxenlight failed.

Precise errors are below. Any hints, please? I am stuck.

Thank you.

2022-01-02 22:34:15.627+0000: libxl:
libxl_device.c:1099:device_backend_callback: unable to remove device
with path /local/domain/4/backend/vif/10/0
2022-01-02 22:34:15.668+0000: libxl: libxl.c:1669:devices_destroy_cb:
libxl__devices_destroy failed for 10
2022-01-03 17:13:23.330+0000: libxl:
libxl_pci.c:1202:libxl__device_pci_reset: The kernel doesn't support
reset from sysfs for PCI device 0000:00:14.0
2022-01-03 17:18:48.724+0000: libxl:
libxl_pci.c:1202:libxl__device_pci_reset: The kernel doesn't support
reset from sysfs for PCI device 0000:00:14.0
2022-01-03 17:28:34.904+0000: libxl:
libxl_pci.c:1202:libxl__device_pci_reset: The kernel doesn't support
reset from sysfs for PCI device 0000:00:14.0
2022-01-03 17:28:35.045+0000: libxl: libxl_pci.c:1520:do_pci_remove:
xc_physdev_unmap_pirq irq=16: Invalid argument
2022-01-04 20:01:03.071+0000: libxl:
libxl_pci.c:1202:libxl__device_pci_reset: The kernel doesn't support
reset from sysfs for PCI device 0000:00:14.0
2022-01-04 20:05:01.984+0000: libxl:
libxl_pci.c:1202:libxl__device_pci_reset: The kernel doesn't support
reset from sysfs for PCI device 0000:00:14.0
2022-01-04 20:05:02.139+0000: libxl: libxl_pci.c:1520:do_pci_remove:
xc_physdev_unmap_pirq irq=16: Invalid argument
2022-01-04 20:06:52.453+0000: libxl:
libxl_device.c:1099:device_backend_callback: unable to remove device
with path /local/domain/14/backend/vif/15/0
2022-01-04 20:06:52.516+0000: libxl: libxl.c:1669:devices_destroy_cb:
libxl__devices_destroy failed for 15
2022-01-04 20:06:54.686+0000: libxl:
libxl_device.c:983:libxl__initiate_device_generic_remove: backend
/local/domain/3/backend/vif/4/0 already removed, cleanup frontend only
2022-01-04 20:06:57.799+0000: libxl:
libxl_device.c:1099:device_backend_callback: unable to remove device
with path /local/domain/4/backend/vif/10/0
2022-01-04 20:06:57.850+0000: libxl: libxl.c:1669:devices_destroy_cb:
libxl__devices_destroy failed for 10
2022-01-04 20:06:58.222+0000: libxl:
libxl_device.c:1099:device_backend_callback: unable to remove device
with path /local/domain/4/backend/vif/14/0
2022-01-04 20:06:58.270+0000: libxl: libxl.c:1669:devices_destroy_cb:
libxl__devices_destroy failed for 14
2022-01-04 20:06:58.747+0000: libxl:
libxl_device.c:1099:device_backend_callback: unable to remove device
with path /local/domain/4/backend/vif/9/0
2022-01-04 20:06:58.794+0000: libxl: libxl.c:1669:devices_destroy_cb:
libxl__devices_destroy failed for 9
2022-01-04 20:07:00.847+0000: libxl:
libxl_device.c:1099:device_backend_callback: unable to remove device
with path /local/domain/4/backend/vif/8/0
2022-01-04 20:07:00.883+0000: libxl: libxl.c:1669:devices_destroy_cb:
libxl__devices_destroy failed for 8
2022-01-04 20:07:13.887+0000: libxl:
libxl_device.c:983:libxl__initiate_device_generic_remove: backend
/local/domain/4/backend/vif/7/0 already removed, cleanup frontend only
2022-01-04 20:07:39.004+0000: libxl:
libxl_linux.c:155:libxl__loopdev_cleanup: unable to release device
/dev/loop0: No such device or address
2022-01-04 22:07:31.083+0000: libxl:
libxl_device.c:1391:libxl__wait_for_backend: Backend
/local/domain/0/backend/pci/9/0 not ready
2022-01-04 22:07:31.092+0000: libxl:
libxl_pci.c:1364:libxl__add_pcidevs: libxl_device_pci_add failed: -3
2022-01-04 22:07:31.092+0000: libxl:
libxl_create.c:1517:domcreate_attach_devices: unable to add pci devices
2022-01-04 22:07:41.165+0000: libxl:
libxl_device.c:1391:libxl__wait_for_backend: Backend
/local/domain/0/backend/pci/9/0 not ready
2022-01-04 22:08:49.315+0000: libxl:
libxl_device.c:1391:libxl__wait_for_backend: Backend
/local/domain/0/backend/pci/11/0 not ready
2022-01-04 22:08:49.315+0000: libxl:
libxl_pci.c:1364:libxl__add_pcidevs: libxl_device_pci_add failed: -3
2022-01-04 22:08:49.315+0000: libxl:
libxl_create.c:1517:domcreate_attach_devices: unable to add pci devices
2022-01-04 22:08:59.390+0000: libxl:
libxl_device.c:1391:libxl__wait_for_backend: Backend
/local/domain/0/backend/pci/11/0 not ready