On Fri, Aug 18, 2023 at 11:08 AM Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote: > > On Fri, Aug 18, 2023 at 08:01:54AM +0800, Kai-Heng Feng wrote: > > On Thu, Aug 17, 2023 at 10:22 PM Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote: > > > > > > On Thu, Aug 17, 2023 at 10:07:37AM -0400, Alan Stern wrote: > > > > On Thu, Aug 17, 2023 at 05:33:05PM +0800, Kai-Heng Feng wrote: > > > > > HP ProOne 440 G10 AIO sometimes cannot suspend as xHCI wakes up the > > > > > system: > > > > > [ 445.814574] hub 2-0:1.0: hub_suspend > > > > > [ 445.814652] usb usb2: bus suspend, wakeup 0 > > > > > [ 445.824629] xhci_hcd 0000:00:14.0: Port change event, 1-11, id 11, portsc: 0x202a0 > > > > > > > > What is the meaning of the 0x202a0 bits? What caused this wakeup? > > > > > > And more to the point, given that the previous line says "wakeup 0", why > > > should any port change event cause a wakeup? > > > > I think the controller and roothub have to deal with the interrupt > > about disconnecting regardless of the remote wakeup setting. > > This seems to contradict what you wrote in an earlier email: Nothing is contradicting, what I mentioned is the wakeup of USB touchpanel, not the controller or root hub. > > > > If remote wakeup isn't enabled then the do_wakeup variable will be 0, > > > so your patch wouldn't make any difference. The question is what > > > happens when remote wakeup _is_ enabled. > > > > Nothing happens either per my testing. > > > > For USB keyboard, the remote wakeup is enabled, unplugging it when > > suspend is suspended doesn't wake the system up, despite of PORT_WKDISC_E being set. > > Plugging it back doesn't wake the system up either, despite of PORT_WKCONN_E. > > You appear to be saying that when wakeup is disabled, unplugging a > device will wake up the system -- but when wakeup is enabled, unplugging > a device will not wake up the system! No, what I was saying is that when PORT_WKCONN_E and PORT_WKDISC_E are set, plugging/unplugging USB doesn't wake up the system from suspended state. What it really does for this case is to hinder the suspending process. > > Is that really what you meant? It doesn't make sense. Probably means > there's a bug in the HCD. > > The point I'm trying to get at is that if wakeups are disabled for both > the host controller and the root hub then _nothing_ should generate an > interrupt or wakeup request. Not pressing a key, not unplugging a > device... nothing. But if wakeup _is_ enabled for both the controller > and the root hub, then any of those actions should generate an interrupt > and wake up the system. Like above, the wakeup I mentioned is on the USB touchpanel itself, not on the controller and roothub. There's no IRQ generated when controller's wakeup is disabled. > > If wakeup is enabled for the host controller but not for the root hub, > then unplugging a device from the root hub should not generate a wakeup > request or an interrupt. But things like pressing a key on a > wakeup-enabled keyboard should. (In other words, the root hub shouldn't > generate any wakeup requests on its own but it should relay wakeup > requests that it receives from downstream devices.) However, it's > understandable if the system doesn't behave properly in this case since > it's kind of an odd situation. Do you mean when the system is suspended, or system is still suspending? The issue only happens when the system is suspending. Kai-Heng > > Alan Stern
