Messages in this thread | | | Date | Fri, 28 Apr 2023 13:17:10 +0300 | From | Mathias Nyman <> | Subject | Re: [PATCH] usb: host: xhci: Avoid XHCI resume delay if SSUSB device is not present |
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On 27.4.2023 22.01, Wesley Cheng wrote: > There is a 120ms delay implemented for allowing the XHCI host controller to > detect a U3 wakeup pulse. The intention is to wait for the device to retry > the wakeup event if the USB3 PORTSC doesn't reflect the RESUME link status > by the time it is checked. As per the USB3 specification: > > tU3WakeupRetryDelay ("Table 7-12. LTSSM State Transition Timeouts") > > This would allow the XHCI resume sequence to determine if the root hub > needs to be also resumed. However, in case there is no device connected, > or if there is only a HSUSB device connected, this delay would still affect > the overall resume timing. > > Since this delay is solely for detecting U3 wake events (USB3 specific) > then ignore this delay for the disconnected case and the HSUSB connected > only case. > > Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com> > --- > drivers/usb/host/xhci.c | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-) > > diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c > index 78790dc13c5f..7a86cd683502 100644 > --- a/drivers/usb/host/xhci.c > +++ b/drivers/usb/host/xhci.c > @@ -834,7 +834,8 @@ static bool xhci_pending_portevent(struct xhci_hcd *xhci) > while (port_index--) { > portsc = readl(ports[port_index]->addr); > if (portsc & PORT_CHANGE_MASK || > - (portsc & PORT_PLS_MASK) == XDEV_RESUME) > + (portsc & PORT_PLS_MASK) == XDEV_RESUME || > + !(portsc & PORT_CONNECT)) > return true; This change will report a pending port event at the first empty roothub port.
I think we are looking for something like this instead (pseudo):
@@ -1116,7 +1116,7 @@ int xhci_resume(struct xhci_hcd *xhci, bool hibernated) * the first wake signalling failed, give it that chance. */ pending_portevent = xhci_pending_portevent(xhci); - if (!pending_portevent) { + if (!pending_portevent && usb3_devices_connected && runtime_resume) { msleep(120); pending_portevent = xhci_pending_portevent(xhci); }
Thanks Mathias
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