Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2992759AbbEPAGk (ORCPT ); Fri, 15 May 2015 20:06:40 -0400 Received: from v094114.home.net.pl ([79.96.170.134]:42551 "HELO v094114.home.net.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S2992439AbbEPAGi (ORCPT ); Fri, 15 May 2015 20:06:38 -0400 From: "Rafael J. Wysocki" To: NeilBrown Cc: Thomas Gleixner , linux-kernel@vger.kernel.org, GTA04 owners , linux-pm@vger.kernel.org, Kalle Jokiniemi , Peter Zijlstra Subject: Re: [PATCH - RESEND] IRQ: don't suspend nested_thread irqs over system suspend. Date: Sat, 16 May 2015 02:31:52 +0200 Message-ID: <1784621.LW7069gAjl@vostro.rjw.lan> User-Agent: KMail/4.11.5 (Linux/4.0.0+; KDE/4.11.5; x86_64; ; ) In-Reply-To: <20150224132805.385a56a5@notabene.brown> References: <20150224132805.385a56a5@notabene.brown> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="utf-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3465 Lines: 100 On Tuesday, February 24, 2015 01:28:05 PM NeilBrown wrote: > > --Sig_/GFnrHDc1Bs/XVRdbvRQTN5O > Content-Type: text/plain; charset=US-ASCII > Content-Transfer-Encoding: quoted-printable > > > > Nested IRQs can only fire when the parent irq fires. > So when the parent is suspended, there is no need to suspend > the child irq. > > Suspending nested irqs can cause a problem is they are suspended or > resumed in the wrong order. > If an interrupt fires while the parent is active but the child is > suspended, then the interrupt will not be acknowledged properly > and so an interrupt storm can result. > This is particularly likely if the parent is resumed before > the child, and the interrupt was raised during suspend. > > Ensuring correct ordering would be possible, but it is simpler > to just never suspend nested interrupts. > > Signed-off-by: NeilBrown We need to make some progress here. Can you please resend it again for people to have a fresh look (and CC PeterZ this time too)? > > --- > This is a resend of a patch sent at the end of January 2015. > Rafael seemed happy with it, but I receive no other response so I'm resendi= > ng. > > Thanks, > NeilBrown > > > diff --git a/kernel/irq/pm.c b/kernel/irq/pm.c > index 3ca532592704..40cbcfb7fc43 100644 > --- a/kernel/irq/pm.c > +++ b/kernel/irq/pm.c > @@ -118,6 +118,8 @@ void suspend_device_irqs(void) > unsigned long flags; > bool sync; > =20 > + if (irq_settings_is_nested_thread(desc)) > + continue; > raw_spin_lock_irqsave(&desc->lock, flags); > sync =3D suspend_device_irq(desc, irq); > raw_spin_unlock_irqrestore(&desc->lock, flags); > @@ -158,6 +160,8 @@ static void resume_irqs(bool want_early) > =20 > if (!is_early && want_early) > continue; > + if (irq_settings_is_nested_thread(desc)) > + continue; > =20 > raw_spin_lock_irqsave(&desc->lock, flags); > resume_irq(desc, irq); > > --Sig_/GFnrHDc1Bs/XVRdbvRQTN5O > Content-Type: application/pgp-signature > Content-Description: OpenPGP digital signature > > -----BEGIN PGP SIGNATURE----- > Version: GnuPG v2 > > iQIVAwUBVOvhtTnsnt1WYoG5AQKnXxAAjQnaCA2UPMaoXcwoP/Qx1MJpMSjW6Q6v > b7NiJTm7ltcKoPBN4y2//p0Wk6BEKT+nCbfqFacj4+MxfjrC4qtjIpsL6lVxi2Iz > sBdbhdkKdUsX6ueRKWv5ifK9qbDzBje7QUcGDrJ/9n80rvbVB5AnSH8bM0TADs2W > bfg5xWAMLfBZq4yhMTgOkPx7D9LMk6/HmlR55ZEC7JvZo6yKwifyQi18k1wfDlLZ > FobxyB6/MexRpjG9RXLpp4MJLV7BV0b6wQhZWWYSFhxVcuYxb9u7BHWumtO9fCMy > fgIzSVsZHuPxTH+ct7fbj+Pat+Y38c5RYpq4ojWJP2FnrGjEnrPt+dpw6AnbkPme > JudzHus6HhgUu5vLdT/Hu5i1qhVcQVe7OaweqhGs1BReGYX7AVPAsVzJAJ09Fwyb > vNIbfuPoTWVI1cz9VV7VgbFHwZgq9/yhk9KhvRaypaMTeuWKbcf2SgiX315w2e21 > D3Gxa6FDKc+CmnDycrx0eALtfCDp86gR2yeOeiCPAGUp8ICJ5vvAJcnxYVPYzt64 > JBBILBwzRV/7LNzbkYWEFlq4CCm9HhmkN4/HDC7tMcxCqQoVFTK0eGn5nz9kFZ6x > MaUyhhakwK+cAx1bVmTZ+gdBxnaa31p26c2OFdv2VRFnJlFC2X+vc9GFuz8KUZCD > d43mKkWNdWQ= > =vmFh > -----END PGP SIGNATURE----- > > --Sig_/GFnrHDc1Bs/XVRdbvRQTN5O-- > -- > To unsubscribe from this list: send the line "unsubscribe linux-pm" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/