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Date: Thu, 04 Aug 2011 12:58:46 +0530 From: "Koul, Vinod" <vinod.koul@...el.com> To: viresh kumar <viresh.kumar@...com> Cc: Russell King - ARM Linux <linux@....linux.org.uk>, Pratyush ANAND <pratyush.anand@...com>, Rajeev KUMAR <rajeev-dlh.kumar@...com>, Armando VISCONTI <armando.visconti@...com>, Bhupesh SHARMA <bhupesh.sharma@...com>, "linus.walleij@...aro.org" <linus.walleij@...aro.org>, "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>, Vipin KUMAR <vipin.kumar@...com>, Shiraz HASHIM <shiraz.hashim@...com>, Amit VIRDI <Amit.VIRDI@...com>, Vipul Kumar SAMAR <vipulkumar.samar@...com>, "viresh.linux@...il.com" <viresh.linux@...il.com>, Deepak SIKRI <deepak.sikri@...com>, "dan.j.williams@...el.com" <dan.j.williams@...el.com>, "linux-arm-kernel@...ts.infradead.org" <linux-arm-kernel@...ts.infradead.org> Subject: Re: [PATCH V2 08/20] dmaengine/amba-pl08x: support runtime PM On Thu, 2011-08-04 at 12:01 +0530, viresh kumar wrote: > On 08/04/2011 11:06 AM, Koul, Vinod wrote: > > On Thu, 2011-08-04 at 10:49 +0530, viresh kumar wrote: > >> On 08/03/2011 06:09 PM, Russell King - ARM Linux wrote: > >>> On Mon, Aug 01, 2011 at 03:07:18PM +0530, Viresh Kumar wrote: > >> @@ -405,6 +406,7 @@ pl08x_get_phy_channel(struct pl08x_driver_data *pl08x, > >> return NULL; > >> } > >> > >> + pm_runtime_get_sync(&pl08x->adev->dev); > > this should be ideally one of the first things you would do not last. > > get_sync will ensure your .runtime_resume callback is called before it > > returns (if its suspended) > >> return ch; > >> } > > Until this point we are not touching the registers at all. And they will > accessed after this point only. But from maintainability POV it should be at the start. > > >> + pm_runtime_put(&adev->dev); > > _put is probe looks suspect, why do you need this here > > To save power. > > > as you are already setting the status as active, this _put will decrement your > > usage count and possibly call your runtime_suspend > > We set status as active, as amba/bus layer has enabled it before calling > probe and it doesn't put it. > > As DMA will not be used until get_phy_channel() is called, so we can save > some energy here too. So i put it here. > -- ~Vinod -- 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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