From: tony@atomide.com (Tony Lindgren) Date: Mon, 19 May 2014 12:36:22 -0700 Subject: [PATCH] ARM: OMAP4: Fix the boot regression with CPU_IDLE enabled In-Reply-To: <537A4827.30604@linaro.org> References: <5374FE61.50901@linaro.org> <5374FF5B.8050702@ti.com> <5375079E.3060305@ti.com> <537615EA.3020809@ti.com> <20140516212942.GK12881@atomide.com> <537A3544.1050307@linaro.org> <20140519172338.GJ4849@atomide.com> <537A408F.7070301@ti.com> <20140519175157.GK4849@atomide.com> <537A4827.30604@linaro.org> Message-ID: <20140519193622.GA11945@atomide.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org * Daniel Lezcano [140519 11:07]: > On 05/19/2014 07:51 PM, Tony Lindgren wrote: > >* Santosh Shilimkar [140519 10:35]: > >>On Monday 19 May 2014 01:23 PM, Tony Lindgren wrote: > >>>* Daniel Lezcano [140519 09:46]: > >>>>On 05/16/2014 11:29 PM, Tony Lindgren wrote: > >>>>> > >>>>>And just to recap, this problem can be reproduced with current > >>>>>Linux next with omap2plus_defconfig with CONFIG_CPU_IDLE enabled. The > >>>>>system should hang during the boot at some point. > >>>> > >>>>I can take the time to investigate a bit more but not right now. What is > >>>>your deadline before committing the reverts ? > >>> > >>>Well we do have several automated build and boot systems failing > >>>because of this with multi_v7_defconfig. And users are complaining, > >>>see this report from Tobias Jakobi: > >>> > >>>https://bugzilla.kernel.org/show_bug.cgi?id=75421 > >>> > >>>It seems that doing the revert is not enough based on the > >>>page above. > >>> > >>Thats not true. The above link used the half patch and not the > >>updated patch. Updated patch worked for Alex also. As you can > >>see they saw RCU stalls and they go away after the updated patch. > >> > >>Can you please point them to try out the updated patch ? > > > >OK good point. I added a link to the updated patch in > >bugzilla. > > > >>>I'd prefer we'd fix this issue properly for sure, it seems that > >>>we're not quite understanding what's going on. And this might > >>>hit other platforms too when they start implementing deeper > >>>PM idle states in the mainline kernel. > >>> > >>I am certain that the updated patch fixed the regression > >>for sure. The issue is really not generic enough since its related > >>an OMAP ROM errata which needs that special handling of > >>interrupt re-trigger etc. You don't need that for other platforms > >>so they are not likely get affected. > > > >OK makes sense to me considering the ROM code. Daniel, are you OK > >with that or do you still want to investigate further? > > For the moment I am a bit short in time for some other tasks. So feel free > to apply the revert and I will look for a proper fix when I will have time. Added Tobias to Cc. At the bugzilla link Tobias is saying he used the right patch from Santosh to test and it still fails. Regards, Tony