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

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Date:   Mon, 6 Jun 2022 13:45:51 -0700
From:   Matthias Kaehlcke <mka@...omium.org>
To:     Krishna Kurapati <quic_kriskura@...cinc.com>
Cc:     Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Rob Herring <robh+dt@...nel.org>,
        Andy Gross <agross@...nel.org>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Felipe Balbi <balbi@...nel.org>,
        Stephen Boyd <swboyd@...omium.org>,
        Doug Anderson <dianders@...omium.org>,
        Mathias Nyman <mathias.nyman@...el.com>,
        devicetree@...r.kernel.org, linux-arm-msm@...r.kernel.org,
        linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-pm@...r.kernel.org, quic_pkondeti@...cinc.com,
        quic_ppratap@...cinc.com, quic_vpulyala@...cinc.com,
        Sandeep Maheswaram <quic_c_sanm@...cinc.com>
Subject: Re: [PATCH v20 2/5] usb: dwc3: core: Host wake up support from
 system suspend

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@...cinc.com>
> > 
> > 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@...cinc.com>
> > Signed-off-by: Krishna Kurapati <quic_kriskura@...cinc.com>
> > Reviewed-by: Pavankumar Kondeti <quic_pkondeti@...cinc.com>
> > ---
> >  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
> >