Re: [PATCH v10 2/6] usb: dwc3: core: Host wake up support from system suspend

[Sandeep Maheswaram]

On 1/18/2022 2:27 PM, Jun Li wrote:
> Sandeep Maheswaram <quic_c_sanm@xxxxxxxxxxx> 于2022年1月17日周一 22:03写道：
> > Avoiding phy powerdown when wakeup capable devices are connected
> > by checking wakeup property of xhci plat device.
> > Phy should be on to wake up the device from suspend using wakeup capable
> > devices such as keyboard and mouse.
> >
> > Signed-off-by: Sandeep Maheswaram <quic_c_sanm@xxxxxxxxxxx>
> > Tested-by: Brian Norris <briannorris@xxxxxxxxxxxx>
> > ---
> > Remove redundant else part in dwc3_resume_common. This will not be
> > required if GDSC is always on during suspend/resume.
> >
> >
> >   drivers/usb/dwc3/core.c | 4 ++--
> >   1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
> > index f4c0995..e7a5e3f 100644
> > --- a/drivers/usb/dwc3/core.c
> > +++ b/drivers/usb/dwc3/core.c
> > @@ -1789,7 +1789,7 @@ static int dwc3_suspend_common(struct dwc3 *dwc, pm_message_t msg)
> >                  dwc3_core_exit(dwc);
> >                  break;
> >          case DWC3_GCTL_PRTCAP_HOST:
> > -               if (!PMSG_IS_AUTO(msg)) {
> > +               if (!PMSG_IS_AUTO(msg) && !device_may_wakeup(&dwc->xhci->dev)) {
> >                          dwc3_core_exit(dwc);
> >                          break;
> >                  }
> > @@ -1850,7 +1850,7 @@ static int dwc3_resume_common(struct dwc3 *dwc, pm_message_t msg)
> >                  spin_unlock_irqrestore(&dwc->lock, flags);
> >                  break;
> >          case DWC3_GCTL_PRTCAP_HOST:
> > -               if (!PMSG_IS_AUTO(msg)) {
> > +               if (!PMSG_IS_AUTO(msg) && !device_may_wakeup(&dwc->xhci->dev)) {
> If XHCI_SKIP_PHY_INIT is not set, I see the usb core will help to
> handle phy power on/off and init/exit via drivers/usb/core/phy.c, so
> if the wakeup is enabled for controller, then finally the phy will not
> be power off/exit. I am wondering if this change is actually required if
> that is the case.
>
> Sorry for the late comment.
>
> Li Jun
The patch is to avoid phy power off in case only if some wakeup capable 
devices are connected.

Regarding  XHCI_SKIP_PHY_INIT we are setting  in this patch

https://patchwork.kernel.org/project/linux-arm-msm/patch/1640153383-21036-1-git-send-email-quic_c_sanm@xxxxxxxxxxx/

> >                          ret = dwc3_core_init_for_resume(dwc);
> >                          if (ret)
> >                                  return ret;
> > --
> > 2.7.4