From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ozlabs.org (ozlabs.org [IPv6:2401:3900:2:1::2]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id EF96B1A0018 for ; Tue, 1 Jul 2014 13:15:58 +1000 (EST) Message-ID: <1404184557.18325.32.camel@ale.ozlabs.ibm.com> Subject: Re: [PATCH] powerpc/powernv: Check for IRQHAPPENED before sleeping From: Michael Neuling To: Michael Ellerman Date: Mon, 30 Jun 2014 22:15:57 -0500 In-Reply-To: <1404175926.30002.1.camel@concordia> References: <20140630062404.29315.23382.stgit@preeti.in.ibm.com> <1404175926.30002.1.camel@concordia> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Cc: linux-kernel@vger.kernel.org, shreyas@linux.vnet.ibm.com, Preeti U Murthy , linuxppc-dev@lists.ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Tue, 2014-07-01 at 10:52 +1000, Michael Ellerman wrote: > On Mon, 2014-06-30 at 11:54 +0530, Preeti U Murthy wrote: > > Commit 8d6f7c5a: "powerpc/powernv: Make it possible to skip the IRQHAPP= ENED > > check in power7_nap()" added code that prevents even cores which enter = sleep > > on idle, from checking for pending interrupts. Fix this. >=20 > To be clear, it is a bug in the original commit. Mikey and I pair program= med > that code, and he was *definitely* typing at that point ;) It's always nice to know that in battle a comrade will throw himself on a grenade to save you. :-P Actually, I'm pretty sure this happened when you were away (probably on a beach somewhere), I was forward porting the patch set, hit a conflict and fucked it up. =20 Mikey >=20 > Can you please include in the changelog what the symptom of the bug is, a= nd > have you seen it in practice? >=20 > The bad commit went into 3.16-rc1, so we don't need to backport this to a= ny > stable release. >=20 > cheers >=20 > > diff --git a/arch/powerpc/kernel/idle_power7.S b/arch/powerpc/kernel/id= le_power7.S > > index 2480256..5cf3d36 100644 > > --- a/arch/powerpc/kernel/idle_power7.S > > +++ b/arch/powerpc/kernel/idle_power7.S > > @@ -131,7 +131,7 @@ _GLOBAL(power7_nap) > > =20 > > _GLOBAL(power7_sleep) > > li r3,1 > > - li r4,0 > > + li r4,1 > > b power7_powersave_common > > /* No return */ > > =20 > >=20 >=20 >=20 >=20 >=20 >=20