Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752412AbaFWWYs (ORCPT ); Mon, 23 Jun 2014 18:24:48 -0400 Received: from mail-we0-f173.google.com ([74.125.82.173]:44864 "EHLO mail-we0-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751179AbaFWWYq (ORCPT ); Mon, 23 Jun 2014 18:24:46 -0400 Message-ID: <53A8A917.8090706@gmail.com> Date: Tue, 24 Jun 2014 00:24:23 +0200 From: Tomasz Figa User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.6.0 MIME-Version: 1.0 To: Kevin Hilman , Doug Anderson CC: Wolfram Sang , Kukjin Kim , Javier Martinez Canillas , naveen krishna , Jingoo Han , Jean Delvare , Simon Glass , Paul Gortmaker , Masanari Iida , Sachin Kamat , "linux-i2c@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , linux-samsung-soc , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH] i2c: exynos5: Properly use the "noirq" variants of suspend/resume References: <1403155273-1057-1-git-send-email-dianders@chromium.org> <7h8uosyc3k.fsf@paris.lan> <7hwqcbs166.fsf@paris.lan> <7h7g4brx6w.fsf@paris.lan> <53A4CADA.4030002@gmail.com> <7ha993p8v4.fsf@paris.lan> In-Reply-To: <7ha993p8v4.fsf@paris.lan> X-Enigmail-Version: 1.6 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 24.06.2014 00:19, Kevin Hilman wrote: > Doug Anderson writes: > > [...] > >> On Fri, Jun 20, 2014 at 4:59 PM, Tomasz Figa wrote: >>> >>> I'm not sure noirq is going to work correctly, at least not with current >>> callbacks. I can see a call to clk_prepare_enable() there which needs to >>> acquire a mutex. >> >> Nice catch, thanks! :) >> >> OK, looking at that now. Interestingly this doesn't seem to cause us >> problems in our ChromeOS 3.8 tree. I just tried enabling: >> CONFIG_DEBUG_ATOMIC_SLEEP=y >> >> ...and confirmed that I got it on right: >> >> # zgrep -i atomic /proc/config.gz >> CONFIG_DEBUG_ATOMIC_SLEEP=y >> >> I can suspend/resume with no problems. My bet is that it works fine because: >> >> * resume_noirq is not considered "atomic" in the sense enforced by >> CONFIG_DEBUG_ATOMIC_SLEEP (at least not in 3.8--I haven't tried on >> ToT) > > The reason is because "noirq" in the suspend/resume path actually means > no *device* IRQs for that specific device. > > It's often assumed that the "noirq" callbacks are called with *all* > interrupts disabled, but that's not the case. Only the IRQs for that > specific device are disabled when its noirq callbacks run. Thanks for clarifying this. This means that we should be fine with the noirq variant then. Best regards, Tomasz -- 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/