linux-kernel - RE: [PATCH 4/4] mfd: global Suspend and resume support of ehci and ohci

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Date:	Wed, 29 Jun 2011 14:47:47 -0400 (EDT)
From:	Alan Stern <stern@...land.harvard.edu>
To:	Partha Basak <p-basak2@...com>
cc:	Keshava Munegowda <keshava_mgowda@...com>,
	Kevin Hilman <khilman@...com>, <linux-usb@...r.kernel.org>,
	<linux-omap@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
	Felipe Balbi <balbi@...com>, Anand Gadiyar <gadiyar@...com>,
	<sameo@...ux.intel.com>, <parthab@...ia.ti.com>,
	<tony@...mide.com>, Benoit Cousson <b-cousson@...com>,
	<paul@...an.com>
Subject: RE: [PATCH 4/4] mfd: global Suspend and resume support of ehci and
 ohci

On Wed, 29 Jun 2011, Partha Basak wrote:

> >-----Original Message-----
> >From: Alan Stern [mailto:stern@...land.harvard.edu]
> >Sent: Wednesday, June 29, 2011 11:03 PM
> >To: Munegowda, Keshava
> >Cc: Kevin Hilman; linux-usb@...r.kernel.org; linux-omap@...r.kernel.org;
> >linux-kernel@...r.kernel.org; balbi@...com; gadiyar@...com;
> >sameo@...ux.intel.com; parthab@...ia.ti.com; tony@...mide.com; b-
> >cousson@...com; paul@...an.com
> >Subject: Re: [PATCH 4/4] mfd: global Suspend and resume support of ehci
> >and ohci
> >
> >On Wed, 29 Jun 2011, Munegowda, Keshava wrote:
> >
> >> for usb host case , I am seeing that the pm_runtime_get_sync
> >>
> >>
> >> static int rpm_resume(struct device *dev, int rpmflags)
> >> {
> >>   ............
> >>  ..........
> >> 	if (dev->pwr_domain) {
> >> 		callback = dev->pwr_domain->ops.runtime_resume;
> >> 		if(!strcmp(dev_name(dev),"usbhs_omap"))
> >> 			 pr_err("dev->pwr_domain->ops.runtime_resume");
> >> 	}
> >> 	else if (dev->type && dev->type->pm) {
> >> 		callback = dev->type->pm->runtime_resume;
> >> 		if(!strcmp(dev_name(dev),"usbhs_omap"))
> >> 			 pr_err("dev->type->pm->runtime_resume");
> >> 	}
> >> 	else if (dev->class && dev->class->pm) {
> >> 		callback = dev->class->pm->runtime_resume;
> >> 		if(!strcmp(dev_name(dev),"usbhs_omap"))
> >> 			 pr_err("ev->class->pm->runtime_resume");
> >> 	}
> >> 	else if (dev->bus && dev->bus->pm) {
> >> 		callback = dev->bus->pm->runtime_resume;
> >> 	if(!strcmp(dev_name(dev),"usbhs_omap"))
> >> 		 pr_err("dev->bus->pm->runtime_resume");
> >> 	}
> >> 	else
> >> 		callback = NULL;
> >> }
> >>
> >>
> >> I am seeing that below if statement was hitting true:
> >>
> >> 	if (dev->pwr_domain) {
> >> 		callback = dev->pwr_domain->ops.runtime_resume;
> >> 		if(!strcmp(dev_name(dev),"usbhs_omap"))
> >> 			 pr_err("dev->pwr_domain->ops.runtime_resume");
> >>
> >>
> >> due to this; the driver->runtime_resume was not getting called.
> >>
> >> Any idea on why I am seeing only the dev->pwr_domain is set not
> >> dev->bus && dev->bus->pm is hitting here?
> >
> >Because the PM domain takes precedence over the subsystem for PM
> >callbacks.  If the subsystem routine should be called then the PM
> >domain code has to call it.
> 
> This is taken care of in the pm-domain code:
> static int _od_runtime_resume(struct device *dev)
> {
> 	struct platform_device *pdev = to_platform_device(dev);
> 
> 	omap_device_enable(pdev);
> 
> 	return pm_generic_runtime_resume(dev);
> }
> pm_generic_runtime_resume will in turn call the driver call back.
> 
> int pm_generic_runtime_resume(struct device *dev)
> {
> 	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm :
> NULL;
> 	int ret;
> 
> 	ret = pm && pm->runtime_resume ? pm->runtime_resume(dev) : 0;
> 
> 	return ret;
> }

You appear to be contradicting what Keshava wrote: "due to this; the
driver->runtime_resume was not getting called."

You can't both be right.

Alan Stern


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