From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Lezcano Subject: Re: (bisected) Lock up on sh73a0/kzm9g on cpuidle initialization Date: Tue, 25 Nov 2014 23:23:04 +0100 Message-ID: <54750148.207@linaro.org> References: <545BE1DE.6060900@linaro.org> <20141125180159.GI5050@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from mail-wg0-f50.google.com ([74.125.82.50]:52403 "EHLO mail-wg0-f50.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751239AbaKYWXJ (ORCPT ); Tue, 25 Nov 2014 17:23:09 -0500 Received: by mail-wg0-f50.google.com with SMTP id k14so2119179wgh.37 for ; Tue, 25 Nov 2014 14:23:08 -0800 (PST) In-Reply-To: Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: Geert Uytterhoeven , Paul McKenney Cc: Ingo Molnar , Nicolas Pitre , Jiri Kosina , "Rafael J. Wysocki" , Linux PM list , Linux-sh list , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , Magnus Damm On 11/25/2014 10:27 PM, Geert Uytterhoeven wrote: [ ... ] >> Does any sort of system activity (keyboard, network, etc.) unstick t= he >> system? > > Thanks! Unfortunately none of the above helped. > > However, I found the culprit. It turned out to be a platform issue, n= ot an > issue in the generic cpu idle or RCU code. Read on below if you're > interested in the gory details. Else just skip, and sleep well again = tonight ;-) > >> If you have tried all those things without good effect, could you pl= ease >> send along your .config and an alt-sysrq-t dump of all tasks' stacks= ? > > As I didn't manage to trigger a sysrq dump over the serial console, > I just called __handle_sysrq() right before the wait_for_completion()= , after > a small delay. The dump didn't show anything suspicious. Everything > looked the same as on the dual-core Cortex A15, where the problem > doesn't manifest. > > Then I noticed the sched debug output on the A15, which was missing > on the CA9 build. Enabling it on the A9 gave: > > Sched Debug Version: v0.11, > 3.18.0-rc6-kzm9g-reference-04913-gedc89a2a2059c7ff-dirty #101 > ktime : 0.000000 > sched_clk : 0.000000 > cpu_clk : 0.000000 > jiffies : 4294928896 > > Oops, time is not advancing? > > Dmesg also shows (early): > > clocksource_of_init: no matching clocksources found > > and the timer is only initialized much later, after cpu idle initiali= zation: > > sh_cmt e6138000.timer: ch0: used for periodic clock events > > Hacking up a timer node for "arm,cortex-a9-twd-timer" in sh73a0.dtsi > (with some "guessed" values) made it work. > > Thanks! > > Gr{oetje,eeting}s, Hi Geert, thanks for sharing this information. -- Daniel --=20 Linaro.org =E2=94=82 Open source software fo= r ARM SoCs =46ollow Linaro: Facebook | Twitter | Blog