On Tue, Sep 19, 2023 at 03:43:27PM -0700, 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@xxxxxxxxxxx>
> ---
> Depends-on:
> https://lore.kernel.org/linux-usb/20230915143108.1532163-3-mathias.nyman@xxxxxxxxxxxxxxx/
>
> drivers/usb/host/xhci.c | 20 +++++++++++++++++++-
> 1 file changed, 19 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
> index e1b1b64a0723..1855cab1be56 100644
> --- a/drivers/usb/host/xhci.c
> +++ b/drivers/usb/host/xhci.c
> @@ -805,6 +805,18 @@ static void xhci_disable_hub_port_wake(struct xhci_hcd *xhci,
> spin_unlock_irqrestore(&xhci->lock, flags);
> }
>
> +/*
> + * Utilize suspended_ports and bus_suspended to determine if USB3 device is
> + * connected. The bus state bits are set by XHCI hub when root hub udev is
> + * suspended. Used to determine if USB3 remote wakeup considerations need to
> + * be accounted for during XHCI resume.
> + */
> +static bool xhci_usb3_dev_connected(struct xhci_hcd *xhci)
> +{
> + return !!xhci->usb3_rhub.bus_state.suspended_ports ||
> + !!xhci->usb3_rhub.bus_state.bus_suspended;
> +}
> +
> static bool xhci_pending_portevent(struct xhci_hcd *xhci)
> {
> struct xhci_port **ports;
> @@ -968,6 +980,7 @@ int xhci_resume(struct xhci_hcd *xhci, pm_message_t msg)
> int retval = 0;
> bool comp_timer_running = false;
> bool pending_portevent = false;
> + bool usb3_connected = false;
> bool reinit_xhc = false;
>
> if (!hcd->state)
> @@ -1116,9 +1129,14 @@ int xhci_resume(struct xhci_hcd *xhci, pm_message_t msg)
> * Resume roothubs only if there are pending events.
> * USB 3 devices resend U3 LFPS wake after a 100ms delay if
> * the first wake signalling failed, give it that chance.
> + * Avoid this check if there are no devices connected to
> + * the SS root hub. (i.e. HS device connected or no device
> + * connected)
> */
> pending_portevent = xhci_pending_portevent(xhci);
> - if (!pending_portevent && msg.event == PM_EVENT_AUTO_RESUME) {
> + usb3_connected = xhci_usb3_dev_connected(xhci);
> + if (!pending_portevent && usb3_connected &&
> + msg.event == PM_EVENT_AUTO_RESUME) {
> msleep(120);
> pending_portevent = xhci_pending_portevent(xhci);
> }
>
Hi,
This is the friendly patch-bot of Greg Kroah-Hartman. You have sent him
a patch that has triggered this response. He used to manually respond
to these common problems, but in order to save his sanity (he kept
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created. Hopefully you will not take offence and will fix the problem
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Please read the section entitled "The canonical patch format" in the
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If you wish to discuss this problem further, or you have questions about
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