linux-kernel - Re: [PATCH v2 3/3] usb: dwc3: imx8mp: disable auto suspend for host role

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Message-ID: <ft43w567youffka6qwrpbzkwctk3dttwsnaqgx45atwjhoenc7@rbpluqz7xpm4>
Date: Thu, 8 Jan 2026 16:00:10 +0800
From: Xu Yang <xu.yang_2@....com>
To: Thinh Nguyen <Thinh.Nguyen@...opsys.com>
Cc: "gregkh@...uxfoundation.org" <gregkh@...uxfoundation.org>, 
	"shawnguo@...nel.org" <shawnguo@...nel.org>, "s.hauer@...gutronix.de" <s.hauer@...gutronix.de>, 
	"kernel@...gutronix.de" <kernel@...gutronix.de>, "festevam@...il.com" <festevam@...il.com>, 
	"linux-usb@...r.kernel.org" <linux-usb@...r.kernel.org>, "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>, 
	"imx@...ts.linux.dev" <imx@...ts.linux.dev>, 
	"linux-arm-kernel@...ts.infradead.org" <linux-arm-kernel@...ts.infradead.org>, "jun.li@....com" <jun.li@....com>
Subject: Re: [PATCH v2 3/3] usb: dwc3: imx8mp: disable auto suspend for host
 role

On Tue, Dec 16, 2025 at 11:26:40PM +0000, Thinh Nguyen wrote:
> On Fri, Dec 05, 2025, Xu Yang wrote:
> > Do dwc3 core auto suspend enable for device and disable for host
> > , this can make sure dwc3 core device auto suspend setting is
> > correct all the time, the background of disable dwc3 core device
> > auto suspend is to make its parent device suspend immediately
> > (so wakeup enable can be enabled) after xhci-plat device suspended,
> > for device mode, we keep the dwc3 core device auto suspend is to
> > give some wait for gadget to be enumerated.
> > 
> > Note: It's a temporary solution until we switch to using the new
> >       flatten model.
> > 
> > Signed-off-by: Xu Yang <xu.yang_2@....com>
> > 
> > ---
> > Changes in v2:
> >  - add a note suggested by Thinh
> > ---
> >  drivers/usb/dwc3/dwc3-imx8mp.c | 31 +++++++++++++++++++++++++++++++
> >  1 file changed, 31 insertions(+)
> > 
> > diff --git a/drivers/usb/dwc3/dwc3-imx8mp.c b/drivers/usb/dwc3/dwc3-imx8mp.c
> > index 8bece4baecbf..2e13ca588f42 100644
> > --- a/drivers/usb/dwc3/dwc3-imx8mp.c
> > +++ b/drivers/usb/dwc3/dwc3-imx8mp.c
> > @@ -158,11 +158,31 @@ static irqreturn_t dwc3_imx8mp_interrupt(int irq, void *_dwc3_imx)
> >  	return IRQ_HANDLED;
> >  }
> >  
> > +static void dwc3_imx_pre_set_role(struct dwc3 *dwc, enum usb_role role)
> > +{
> > +	if (role == USB_ROLE_HOST)
> > +		/*
> > +		 * For xhci host, we need disable dwc core auto
> > +		 * suspend, because during this auto suspend delay(5s),
> > +		 * xhci host RUN_STOP is cleared and wakeup is not
> > +		 * enabled, if device is inserted, xhci host can't
> > +		 * response the connection.
> > +		 */
> > +		pm_runtime_dont_use_autosuspend(dwc->dev);
> 
> As noted previously, don't we need to unwind this in dwc3_imx8mp_remove
> if the current mode device?

Thanks for the reminder. I check it, dwc3_core_remove() will call
pm_runtime_dont_use_autosuspend(). So it seems unnecessary to unwind it
again in dwc3_imx8mp_remove().

> 
> > +	else
> > +		pm_runtime_use_autosuspend(dwc->dev);
> > +}
> > +
> > +struct dwc3_glue_ops dwc3_imx_glue_ops = {
> > +	.pre_set_role   = dwc3_imx_pre_set_role,
> > +};
> > +
> >  static int dwc3_imx8mp_probe(struct platform_device *pdev)
> >  {
> >  	struct device		*dev = &pdev->dev;
> >  	struct device_node	*node = dev->of_node;
> >  	struct dwc3_imx8mp	*dwc3_imx;
> > +	struct dwc3		*dwc3;
> >  	struct resource		*res;
> >  	int			err, irq;
> >  
> > @@ -240,6 +260,17 @@ static int dwc3_imx8mp_probe(struct platform_device *pdev)
> >  		goto depopulate;
> >  	}
> >  
> > +	dwc3 = platform_get_drvdata(dwc3_imx->dwc3_pdev);
> > +	if (!dwc3) {
> > +		err = dev_err_probe(dev, -EPROBE_DEFER, "failed to get dwc3 platform data\n");
> > +		goto depopulate;
> > +	}
> > +
> > +	dwc3->glue_ops = &dwc3_imx_glue_ops;
> > +
> > +	if (dwc3->dr_mode == USB_DR_MODE_HOST)
> > +		pm_runtime_dont_use_autosuspend(dwc3->dev);
> > +
> >  	err = devm_request_threaded_irq(dev, irq, NULL, dwc3_imx8mp_interrupt,
> >  					IRQF_ONESHOT, dev_name(dev), dwc3_imx);
> >  	if (err) {
> > -- 
> > 2.34.1
> > 
> 
> The question above is trivial. You can add this in v3:
> 
> Acked-by: Thinh Nguyen <Thinh.Nguyen@...opsys.com>

OK.

Thanks,
Xu Yang