On Fri, Apr 10, 2026 at 06:11:59PM +0200, Johan Kroeckel wrote:
> When the UPS is connected to USB (control) the system doesn't suspend
> completely. Hard drives spin down but fans keep running.
>
> Apr 10 17:43:22 singapore kernel: xhci_hcd 0000:00:14.0: PM:
> pci_pm_suspend(): hcd_pci_suspend [usbcore] returns -16
> Apr 10 17:43:22 singapore kernel: xhci_hcd 0000:00:14.0: PM:
> dpm_run_callback(): pci_pm_suspend returns -16
> Apr 10 17:43:22 singapore kernel: xhci_hcd 0000:00:14.0: PM: failed to
> suspend async: error -16
The USB HID support blocks suspend in some cases, all related to the
typical usage of this protocol: human input. Things like "key is
pressed" or just "something is communicating to the device".
Now it seems that your UPS triggers one of those cases. Sadly it is not
possible to access this state from userspace, so no quick check for it.
Also there are no existing quirks that could help.
What you could try:
- A current kernel, to see if it is still the same kind of broken
- If stopping the tool that communicates with the device helps
Bastian
--
The best diplomat I know is a fully activated phaser bank.
-- Scotty
