From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760509AbaGYWtL (ORCPT ); Fri, 25 Jul 2014 18:49:11 -0400 Received: from v094114.home.net.pl ([79.96.170.134]:50138 "HELO v094114.home.net.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1752445AbaGYWtI (ORCPT ); Fri, 25 Jul 2014 18:49:08 -0400 From: "Rafael J. Wysocki" To: Thomas Gleixner Cc: Peter Zijlstra , linux-kernel@vger.kernel.org, Linux PM list Subject: Re: [RFC][PATCH] irq: Rework IRQF_NO_SUSPENDED Date: Sat, 26 Jul 2014 01:07:35 +0200 Message-ID: <2363344.XLlmCjS7fv@vostro.rjw.lan> User-Agent: KMail/4.11.5 (Linux/3.16.0-rc5+; KDE/4.11.5; x86_64; ; ) In-Reply-To: <1663327.PISiM9sMHC@vostro.rjw.lan> References: <20140724212620.GO3935@laptop> <1663327.PISiM9sMHC@vostro.rjw.lan> 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 On Saturday, July 26, 2014 12:25:29 AM Rafael J. Wysocki wrote: > On Friday, July 25, 2014 11:00:12 PM Thomas Gleixner wrote: > > On Fri, 25 Jul 2014, Rafael J. Wysocki wrote: > > > On Friday, July 25, 2014 03:25:41 PM Peter Zijlstra wrote: > > > > OK, so Rafael said there's devices that keep on raising their interrupt > > > > until they get attention. Ideally this won't happen because the device > > > > is suspended etc.. But I'm sure there's some broken piece of hardware > > > > out there that'll make it go boom. > > > > > > So here's an idea. > > > > > > What about returning IRQ_NONE rather than IRQ_HANDLED for "suspended" > > > interrupts (after all, that's what a sane driver would do for a > > > suspended device I suppose)? > > > > > > If the line is really shared and the interrupt is taken care of by > > > the other guy sharing the line, we'll be all fine. > > > > > > If that is not the case, on the other hand, and something's really > > > broken, we'll end up disabling the interrupt and marking it as > > > IRQS_SPURIOUS_DISABLED (if I understand things correctly). > > > > We should not wait 100k unhandled interrupts in that case. We know > > already at the first unhandled interrupt that the shit hit the fan. > > The first one may be a bus glitch or some such. Also I guess we still need to > allow the legitimate "no suspend" guy to handle his interrupts until it gets > too worse. s/worse/bad/ (ah, grammar). > Also does it really hurt to rely on the generic mechanism here? We regard > it as fine at all other times after all. > > > I'll have a deeper look how we can sanitize the whole wake/no_suspend > > logic vs. shared interrupts. > > Cool, thanks! > > > Need to look at the usage sites first. > > There will be more of them, like this: > > https://patchwork.kernel.org/patch/4618531/ > > Essentially, all wakeup interrupts will need at least one no_suspend irqaction > going forward. > > Below is my take on this (untested) in case it is useful for anything. > > It is targeted at the problematic case (that is, a shared interrupt with at least > one irqaction that has IRQF_NO_SUSPEND set and at least one that doesn't) only and > is not supposed to change behavior in the other cases (the do_irqaction thing > shamelessly stolen from the Peter's patch). It drops the IRQD_WAKEUP_STATE check, > because that has the same problem with shared interrupts as no_suspend. Self-correction -> > --- > kernel/irq/handle.c | 21 ++++++++++++++++++--- > kernel/irq/manage.c | 30 +++++++++++++++++++++++++----- > 2 files changed, 43 insertions(+), 8 deletions(-) > > Index: linux-pm/kernel/irq/manage.c > =================================================================== > --- linux-pm.orig/kernel/irq/manage.c > +++ linux-pm/kernel/irq/manage.c [cut] > @@ -446,7 +459,15 @@ EXPORT_SYMBOL(disable_irq); > void __enable_irq(struct irq_desc *desc, unsigned int irq, bool resume) > { > if (resume) { > - if (!(desc->istate & IRQS_SUSPENDED)) { > + if (desc->istate & IRQS_SUSPENDED) { > + desc->istate &= ~IRQS_SUSPENDED; > + if (desc->istate & IRQS_SPURIOUS_DISABLED) { > + pr_err("WARNING! Unhandled events during suspend for IRQ %d\n", irq); -> This should be printed for desc->irqs_unhandled > 0 I suppose. That will cover the cases when we don't have to disable it too. The value of desc->irqs_unhandled can be included into the warning too. Rafael