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Date: Mon, 4 Jul 2011 12:01:24 -0400 (EDT) From: Alan Stern <stern@...land.harvard.edu> To: Felipe Balbi <balbi@...com> cc: Partha Basak <p-basak2@...com>, Keshava Munegowda <keshava_mgowda@...com>, <linux-usb@...r.kernel.org>, <linux-omap@...r.kernel.org>, <linux-kernel@...r.kernel.org>, Anand Gadiyar <gadiyar@...com>, <sameo@...ux.intel.com>, <parthab@...ia.ti.com>, <tony@...mide.com>, Kevin Hilman <khilman@...com>, Benoit Cousson <b-cousson@...com>, <paul@...an.com>, <johnstul@...ibm.com>, Vishwanath Sripathy <vishwanath.bs@...com> Subject: Re: [PATCH 6/6 v2] arm: omap: usb: global Suspend and resume support of ehci and ohci On Mon, 4 Jul 2011, Felipe Balbi wrote: > sounds to me like a bug on pm runtime ? If you're calling > pm_runtime_*_sync() family, shouldn't all calls be _sync() too ? No. This was a deliberate design decision. It minimizes stack usage and it gives a chance for some other child to resume before the parent is powered down. > > static int rpm_suspend(struct device *dev, int rpmflags) > > __releases(&dev->power.lock) __acquires(&dev->power.lock) > > { > > . > > . > > . > > no_callback: > > . > > . > > . > > /* Maybe the parent is now able to suspend. */ > > if (parent && !parent->power.ignore_children && > > !dev->power.irq_safe) { > > spin_unlock(&dev->power.lock); > > > > spin_lock(&parent->power.lock); > > rpm_idle(parent, RPM_ASYNC); > > to me this is bogus, if you called pm_runtime_put_sync() should should > be sync too. Shouldn't it ? No, it shouldn't. > > spin_unlock(&parent->power.lock); > > > > spin_lock(&dev->power.lock); > > } > > This is the reason of directly calling the parent Runtime PM calls from > > the children. > > If directly calling Runtime PM APIs with parent dev-pointer isn't > > acceptable, > > this can be achieved by exporting wrapper APIs from the > > parent and calling them from the chidren .suspend/.resume routines. > > Still no good, IMHO. The real problem here is that you guys are trying to use the runtime PM framework to carry out activities during system suspend. That won't work; it's just a bad idea all round. Use the proper callbacks to do what you want. Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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