From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752234Ab3LMJEF (ORCPT ); Fri, 13 Dec 2013 04:04:05 -0500 Received: from sender1.zohomail.com ([72.5.230.103]:61576 "EHLO sender1.zohomail.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751503Ab3LMJD6 (ORCPT ); Fri, 13 Dec 2013 04:03:58 -0500 X-Greylist: delayed 1325 seconds by postgrey-1.27 at vger.kernel.org; Fri, 13 Dec 2013 04:03:58 EST Date: Fri, 13 Dec 2013 09:41:51 +0100 From: Brecht Machiels To: John Stultz Cc: Borislav Petkov , Message-ID: <1077642371.409848.1386924111059.JavaMail.sas1@[172.29.241.231]> In-Reply-To: <52AA27C7.3090206@linaro.org> References: <20131201220343.2285b12ee1c1e54252dc7dd9@mos6581.org> <529CF1D5. 6010406@linaro.org> <20131202211958.GE7380@pd.tnic> <52AA10F4.6070108@linaro.org> <52AA27C7.3090206@linaro.org> Subject: Re: [REGRESSION] 41c7f74 rtc: Disable the alarm in the hardware (v2) MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-Priority: Medium User-Agent: Zoho Mail X-Mailer: Zoho Mail Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org ---- On Thu, 12 Dec 2013 22:16:55 +0100 John Stultz wrote ---- > On 12/12/2013 11:39 AM, John Stultz wrote: > > On 12/05/2013 03:51 AM, Brecht Machiels wrote: > >> On Mon, 02 Dec 2013 22:19:58 +0100, Borislav Petkov wrote: > >> > >>> On Mon, Dec 02, 2013 at 12:47:17PM -0800, John Stultz wrote: > >>>> Ok, sorry about this. I've been hoping we'd get some better insight > >>>> into what's actually happening on these strange BIOSes where disabling > >>>> the irq seems to cause it to scream (powering the system back on when > >>>> its shutdown), in the hopes of having a proper workaround. But despite > >>>> Borislav's efforts, he didn't seem to be able to root cause the issue. > >>> Right, this bug is too nasty - you could generate good random numbers > >>> just from how the hardware behaves. :) And I've been trying to make > >>> sense of what happens but I failed, as you know. :( > >>> > >>> I consider it a huge waste of time and efforts having to deal with such > >>> b0rked hardware instead of throwing it out of the window into the poring > >>> rain while it is still powered. > >>> > >>>> Borislav, could you double check this patch still works on your > >>>> hardware as well? > >>> Well, we have the patch in SLES11: > >>> > >>> http://kernel.opensuse.org/cgit/kernel/commit/?h=SLE11- > >> SP3&id=835398eb94dca7d55acd1a2628372e602ae3252a > >>> and it passed testing. > >>> > >>> From what I see below, your version is equivalent to the one above with > >>> the logic reversed so it should work. I'll still try to get that > >>> affected box and run your version on it but it'll take a while. > >> Hello John and Boris, > >> > >> Thank you for your quick response. And no need for an apology, I can > >> understand your frustration with the way some hardware behaves. > >> > >> I ran with John's patch for a couple of days, and it seems to work. > >> Curiously, the laptop did spontaneously boot the first time that I shut > >> it down with the patched kernel. I have no conclusive explanation for > >> this, but I have noticed that a manual power down is necessary after > >> booting with an unpatched kernel. Simply rebooting with a patched kernel > >> is not enough to stop the spontaneous boots. As far as I can remember, I > >> went directly from my custom kernel (with the v2 patch reverted) to a > >> kernel with your patch applied, so I'm not 100% convinced everything is > >> all right. I should say that I did experience some spontaneous boots when > >> running only Windows XP in the past, so there may be occasions where > >> drivers might not be able to help at all. > > Yea. It seems almost like the RTC_AIE bit is inverted in the hardware or > > something. > > > >> Thankfully, after other shutdowns/hibernates (about 6 in total) the > >> laptop never booted spontaneously. > >> > >> As for killing alarm functionality on the affected systems, I did some > >> quick tests. With the patched kernel, I can set the RTC alarm by echoing > >> to /sys/class/rtc/rtc0/wakealarm, and the machine will boot at the > >> specified time. I have also tried setting the RTC alarm, and then > >> disabling it again by echoing '0' to /sys/class/rtc/rtc0/wakealarm. While > >> this sets the alrm_time to five minutes in the future, alarm_IRQ is set > >> to 'no' and the machine does *not* boot spontaneously 5 minutes after > >> shutting down. So, all seems well, as far as I can see. Unfortunately, I > >> don't know enough about the RTC driver to draw any conclusions from this. > > Ok. Sounds like the patch works fairly well then. I'll go ahead and > > queue it for 3.14 and -stable. > Brecht: Is it OK if I add to the patch: > Tested-by: Brecht Machiels Sure. Thanks, Brecht