Re: [PATCH v20 2/5] usb: dwc3: core: Host wake up support from system suspend

From: Matthias Kaehlcke
Date: Mon Jun 06 2022 - 16:57:19 EST


On Thu, Jun 02, 2022 at 12:35:42PM -0700, Matthias Kaehlcke wrote:
> Hi Krishna,
>
> with this version I see xHCI errors on my SC7180 based system, like
> these:
>
> [ 65.352605] xhci-hcd xhci-hcd.13.auto: xHC error in resume, USBSTS 0x401, Reinit
>
> [ 101.307155] xhci-hcd xhci-hcd.13.auto: WARN: xHC CMD_RUN timeout
>
> After resume a downstream hub isn't enumerated again.
>
> So far I didn't see those with v13, but I aso saw the first error with
> v16.

It also happens with v13, but only when a wakeup capable vUSB <= 2
device is plugged in. Initially I used a wakeup capable USB3 to
Ethernet adapter to trigger the wakeup case, however older versions
of this series that use usb_wakeup_enabled_descendants() to check
for wakeup capable devices didn't actually check for vUSB > 2
devices.

So the case were the controller/PHYs is powered down works, but
the controller is unhappy when the runtime PM path is used during
system suspend.

> On Thu, Jun 02, 2022 at 01:54:34PM +0530, Krishna Kurapati wrote:
> > From: Sandeep Maheswaram <quic_c_sanm@xxxxxxxxxxx>
> >
> > Check wakeup-source property for dwc3 core node to set the
> > wakeup capability. Drop the device_init_wakeup call from
> > runtime suspend and resume.
> >
> > If the dwc3 is wakeup capable, don't power down the USB PHY(s).
> > The glue drivers are expected to take care of configuring the
> > additional wakeup settings if needed based on the dwc3 wakeup
> > capability status. In some SOC designs, powering off the PHY is
> > resulting in higher leakage, so this patch save power on such boards.
> >
> > Signed-off-by: Sandeep Maheswaram <quic_c_sanm@xxxxxxxxxxx>
> > Signed-off-by: Krishna Kurapati <quic_kriskura@xxxxxxxxxxx>
> > Reviewed-by: Pavankumar Kondeti <quic_pkondeti@xxxxxxxxxxx>
> > ---
> > drivers/usb/dwc3/core.c | 9 +++------
> > 1 file changed, 3 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
> > index e027c04..b99d3c2 100644
> > --- a/drivers/usb/dwc3/core.c
> > +++ b/drivers/usb/dwc3/core.c
> > @@ -1787,6 +1787,7 @@ static int dwc3_probe(struct platform_device *pdev)
> >
> > platform_set_drvdata(pdev, dwc);
> > dwc3_cache_hwparams(dwc);
> > + device_init_wakeup(&pdev->dev, of_property_read_bool(dev->of_node, "wakeup-source"));
> >
> > spin_lock_init(&dwc->lock);
> > mutex_init(&dwc->mutex);
> > @@ -1948,7 +1949,7 @@ 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_can_wakeup(dwc->dev)) {
> > dwc3_core_exit(dwc);
> > break;
> > }
> > @@ -2009,7 +2010,7 @@ 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_can_wakeup(dwc->dev)) {
> > ret = dwc3_core_init_for_resume(dwc);
> > if (ret)
> > return ret;
> > @@ -2086,8 +2087,6 @@ static int dwc3_runtime_suspend(struct device *dev)
> > if (ret)
> > return ret;
> >
> > - device_init_wakeup(dev, true);
> > -
> > return 0;
> > }
> >
> > @@ -2096,8 +2095,6 @@ static int dwc3_runtime_resume(struct device *dev)
> > struct dwc3 *dwc = dev_get_drvdata(dev);
> > int ret;
> >
> > - device_init_wakeup(dev, false);
> > -
> > ret = dwc3_resume_common(dwc, PMSG_AUTO_RESUME);
> > if (ret)
> > return ret;
> > --
> > 2.7.4
> >