From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Munegowda, Keshava" Subject: Re: [PATCH 4/4] mfd: global Suspend and resume support of ehci and ohci Date: Wed, 29 Jun 2011 22:07:21 +0530 Message-ID: References: <1306934847-6098-1-git-send-email-keshava_mgowda@ti.com> <1306934847-6098-2-git-send-email-keshava_mgowda@ti.com> <1306934847-6098-3-git-send-email-keshava_mgowda@ti.com> <1306934847-6098-4-git-send-email-keshava_mgowda@ti.com> <1306934847-6098-5-git-send-email-keshava_mgowda@ti.com> <87d3ix5c6y.fsf@ti.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: Sender: linux-usb-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Kevin Hilman Cc: linux-usb-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-omap-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, balbi-l0cyMroinI0@public.gmane.org, gadiyar-l0cyMroinI0@public.gmane.org, sameo-VuQAYsv1563Yd54FQh9/CA@public.gmane.org, parthab-PpE0FKYn9XJWk0Htik3J/w@public.gmane.org, tony-4v6yS6AI5VpBDgjK7y7TUQ@public.gmane.org, b-cousson-l0cyMroinI0@public.gmane.org, paul-DWxLp4Yu+b8AvxtiuMwx3w@public.gmane.org List-Id: linux-omap@vger.kernel.org On Wed, Jun 29, 2011 at 8:52 PM, Munegowda, Keshava wrote: > On Thu, Jun 2, 2011 at 5:36 AM, Kevin Hilman wrote: >> Keshava Munegowda writes: >> >>> From: Keshava Munegowda >>> >>> The global suspend and resume functions for usbhs core driver >>> are implemented.These routine are called when the global suspend >>> and resume occurs. Before calling these functions, the >>> bus suspend and resume of ehci and ohci drivers are called >>> from runtime pm. >>> >>> Signed-off-by: Keshava Munegowda >> >> First, from what I can see, this is only a partial implementation of >> runtime PM. =A0What I mean is that the runtime PM methods are used o= nly >> during the suspend path. =A0The rest of the time the USB host IP blo= ck is >> left enabled, even when nothing is connected. >> >> I tested this on my 3530/Overo board, and verified that indeed the >> usbhost powerdomain hits retention on suspend, but while idle, when >> nothing is connected, I would expect the driver could be clever enou= gh >> to use runtime PM (probably using autosuspend timeouts) to disable t= he >> hardware as well. >> >>> --- >>> =A0drivers/mfd/omap-usb-host.c | =A0103 +++++++++++++++++++++++++++= ++++++++++++++++ >>> =A01 files changed, 103 insertions(+), 0 deletions(-) >>> >>> diff --git a/drivers/mfd/omap-usb-host.c b/drivers/mfd/omap-usb-hos= t.c >>> index 43de12a..32d19e2 100644 >>> --- a/drivers/mfd/omap-usb-host.c >>> +++ b/drivers/mfd/omap-usb-host.c >>> @@ -146,6 +146,10 @@ >>> =A0#define is_ehci_hsic_mode(x) (x =3D=3D OMAP_EHCI_PORT_MODE_HSIC) >>> >>> >>> +/* USBHS state bits */ >>> +#define OMAP_USBHS_INIT =A0 =A0 =A0 =A0 =A0 =A0 =A00 >>> +#define OMAP_USBHS_SUSPEND =A0 4 >> >> These additional state bits don't seem to be necessary. >> >> For suspend, just check 'pm_runtime_is_suspended()' >> >> The init flag is only used in the suspend/resume hooks, but the need= for >> it is a side effect of not correctly using the runtime PM callbacks. >> >> Remember that the runtime PM get/put hooks have usage counting. =A0O= nly >> when the usage count transitions to/from zero is the actual >> hardware-level enable/disable (via omap_hwmod) being done. >> >> The current code is making the assumption that every call to get/put= is >> going to result in an enable/disable of the hardware. >> >> Instead, all of the code that needs to be run only upon actual >> enable/disable of the hardware should be done in the driver's >> runtime_suspend/runtime_resume callbacks. =A0These are only called w= hen >> the hardware actually changes state. >> >> Not knowing that much about the EHCI block, upon first glance, it lo= oks >> like mmuch of what is done in usbhs_enable() should actually be done= in >> the ->runtime_resume() callback, and similarily, much of what is don= e in >> usbhs_disable() should be done in the ->runtime_suspend() callback. > > Kevin, > =A0 do you mean driver->runtime_resume and driver->runtime_resume cal= l backs. > are these call backs from pm_runtime_get_sync and pm_runtime_put_sync= ? 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 =3D dev->pwr_domain->ops.runtime_resume; if(!strcmp(dev_name(dev),"usbhs_omap")) pr_err("dev->pwr_domain->ops.runtime_resume"); }=09 else if (dev->type && dev->type->pm) { callback =3D dev->type->pm->runtime_resume; if(!strcmp(dev_name(dev),"usbhs_omap")) pr_err("dev->type->pm->runtime_resume"); }=09 else if (dev->class && dev->class->pm) { callback =3D dev->class->pm->runtime_resume; if(!strcmp(dev_name(dev),"usbhs_omap")) pr_err("ev->class->pm->runtime_resume"); }=09 else if (dev->bus && dev->bus->pm) { callback =3D dev->bus->pm->runtime_resume; if(!strcmp(dev_name(dev),"usbhs_omap")) pr_err("dev->bus->pm->runtime_resume"); }=09 else callback =3D NULL; } I am seeing that below if statement was hitting true: if (dev->pwr_domain) { callback =3D 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? -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html