From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tony Lindgren Subject: Re: [PATCH 3/3] CBUS: Make retu watchdog behave like a standard Linux watchdog Date: Thu, 15 May 2008 14:46:41 -0700 Message-ID: <20080515214640.GV8928@atomide.com> References: <1210638918-26644-1-git-send-email-tony@atomide.com> <1210638918-26644-2-git-send-email-tony@atomide.com> <1210638918-26644-3-git-send-email-tony@atomide.com> <1210638918-26644-4-git-send-email-tony@atomide.com> <1210639609.20589.13.camel@mort> <20080513011736.GH28999@atomide.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from mho-02-bos.mailhop.org ([63.208.196.179]:56472 "EHLO mho-02-bos.mailhop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753758AbYEOVql (ORCPT ); Thu, 15 May 2008 17:46:41 -0400 Content-Disposition: inline In-Reply-To: <20080513011736.GH28999@atomide.com> Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: Igor Stoppa Cc: linux-omap@vger.kernel.org * Tony Lindgren [080512 18:17]: > * Igor Stoppa [080512 17:56]: > > Hi Tony, > > On Mon, 2008-05-12 at 17:35 -0700, ext Tony Lindgren wrote: > > > Make retu watchdog behave like a standard Linux watchdog. > > >=20 > > > Let the kernel do the kicking until the watchdog device is opened= =2E > >=20 > > This is not always the desidered behavior: the powerdown wd is used= to > > ensure that the whole sw stack is healty: doing the kicking in > > kernelspace for free introduces the case where userspace can get st= uck > > and the device does not powerdown. >=20 > That's why there's CONFIG_WATCHDOG_NOWAYOUT where the ping timer is > not enabled at all, and the watchdog is just set to max until userspa= ce > watchdog software kicking starts. >=20 > > Also the unconditional loading of the maximum value during probe is= not > > aligned with the original reset logic, which was to have the powerd= own > > wd to allow for 2 boot attempts: > >=20 > > -cold boot -> load max value in retu wd (63s) > > -> load 30s in omap wd > > -try to kick both wds >=20 > Well you can set those values via /dev/watchdog too, right? > And then use CONFIG_WATCHDOG_NOWAYOUT. >=20 > And ff CONFIG_WATCHDOG_NOWAYOUT is not set, the kernel ping timer onl= y > happens when /dev/watchdog is not open. >=20 > > if fail, then omap reboots, but retu keeps counting down > >=20 > > -warm boot -> let the retu wd untouched=EF=BB=BF > > -> load 30s in omap wd=EF=BB=BF > > -try to kick both wds > >=20 > > if fail, retu powers down > >=20 > > That was the original idea in 770 times and i still like it. > >=20 > > To conclude, i'd see inkernel kicking more as a debugging feature w= hile > > one is hacking at the kernel than a desirable quality of a stable > > kernel. >=20 > Considering that the /dev/watchdog interface is the standard, I see t= his > patch as the only way we can get this code ever merged upstream. And = it's > easy to patch back the non-standard if you want to. I'll push the first two patches today, third one still needs to be checked. Tony -- To unsubscribe from this list: send the line "unsubscribe linux-omap" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html