Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752123AbbEHIOu (ORCPT ); Fri, 8 May 2015 04:14:50 -0400 Received: from metis.ext.pengutronix.de ([92.198.50.35]:60466 "EHLO metis.ext.pengutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751732AbbEHIOs (ORCPT ); Fri, 8 May 2015 04:14:48 -0400 Date: Fri, 8 May 2015 10:13:55 +0200 From: Sascha Hauer To: Stephen Boyd Cc: Kevin Hilman , Ulf Hansson , Heiko =?iso-8859-15?Q?St=FCbner?= , Geert Uytterhoeven , Andrew Bresticker , Tyler Baker , Doug Anderson , Max Filippov , Alexandre Belloni , Sylwester Nawrocki , Robert Jarzmik , linux-clk@vger.kernel.org, Stefan Wahren , Boris Brezillon , Mike Turquette , Emilio =?iso-8859-15?Q?L=F3pez?= , Michal Simek , Alex Elder , Zhangfei Gao , Jason Cooper , Pawel Moll , Stephen Warren , Santosh Shilimkar , Chao Xie , Maxime Ripard , "linux-arm-kernel@lists.infradead.org" , Barry Song , Peter De Sc hrijver , lkml , Gabriel FERNANDEZ , Tero Kristo , Viresh Kumar , Sascha Hauer , Olof Johansson , Dinh Nguyen , Georgi Djakov Subject: Re: [PATCH v3 0/2] clk: improve handling of orphan clocks Message-ID: <20150508081355.GB6325@pengutronix.de> References: <1429735986-18592-1-git-send-email-heiko@sntech.de> <1981330.kGUrTurMy5@diego> <5543E79F.2080400@codeaurora.org> <22709390.NTAlubMgNB@diego> <55440EDA.4030905@codeaurora.org> <554BD33D.7050907@codeaurora.org> <20150508065318.GA5690@codeaurora.org> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20150508065318.GA5690@codeaurora.org> X-Sent-From: Pengutronix Hildesheim X-URL: http://www.pengutronix.de/ X-IRC: #ptxdist @freenode X-Accept-Language: de,en X-Accept-Content-Type: text/plain X-Uptime: 10:03:48 up 52 days, 19:55, 77 users, load average: 0.08, 0.14, 0.14 User-Agent: Mutt/1.5.21 (2010-09-15) X-SA-Exim-Connect-IP: 2001:67c:670:100:1d::c0 X-SA-Exim-Mail-From: sha@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-kernel@vger.kernel.org Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4082 Lines: 81 On Thu, May 07, 2015 at 11:53:18PM -0700, Stephen Boyd wrote: > On 05/07, Kevin Hilman wrote: > > On Thu, May 7, 2015 at 2:03 PM, Stephen Boyd wrote: > > > On 05/07/15 08:17, Kevin Hilman wrote: > > >> On Fri, May 1, 2015 at 4:40 PM, Stephen Boyd wrote: > > >>> On 05/01/15 15:07, Heiko St?bner wrote: > > >>>> Am Freitag, 1. Mai 2015, 13:52:47 schrieb Stephen Boyd: > > >>>> > > >>>>>> Instead I guess we could hook it less deep into clk_get_sys, like in the > > >>>>>> following patch? > > >>>>> It looks like it will work at least, but still I'd prefer to keep the > > >>>>> orphan check contained to clk.c. How about this compile tested only patch? > > >>>> I gave this a spin on my rk3288-firefly board. It still boots, the clock tree > > >>>> looks the same and it also still defers nicely in the scenario I needed it > > >>>> for. The implementation also looks nice - and of course much more compact than > > >>>> my check in two places :-) . I don't know if you want to put this as follow-up > > >>>> on top or fold it into the original orphan-check, so in any case > > >>>> > > >>>> Tested-by: Heiko Stuebner > > >>>> Reviewed-by: Heiko Stuebner > > >>> Thanks. I'm leaning towards tossing your patch 2/2 and replacing it with > > >>> my patch and a note that it's based on an earlier patch from you. > > >> It appears this has landed in linux-next in the form of 882667c1fcf1 > > >> clk: prevent orphan clocks from being used. A bunch of boot failures > > >> for sunxi in today's linux-next[1] were bisected down to that patch. > > >> > > >> I confirmed that reverting that commit on top of next/master gets > > >> sunxi booting again. > > >> > > >> > > > > > > Thanks for the report. I've removed the two clk orphan patches from > > > clk-next. Would it be possible to try with next-20150507 and > > > clk_ignore_unused on the command line? > > > > That doesn't help. I tried on cubieboard2 and bananapi. > > Thanks for trying. > > > > > > Also we can try to see if > > > critical clocks aren't being forced on by applying this patch and > > > looking for clk_get() failures > > > > From cubieboard2, there's a few that look rather important: > > > > [ 0.000000] Additional per-CPU info printed with stalls. > > [ 0.000000] Build-time adjustment of leaf fanout to 32. > > [ 0.000000] RCU restricting CPUs from NR_CPUS=16 to nr_cpu_ids=2. > > [ 0.000000] RCU: Adjusting geometry for rcu_fanout_leaf=32, nr_cpu_ids=2 > > [ 0.000000] NR_IRQS:16 nr_irqs:16 16 > > [ 0.000000] clk: couldn't get parent clock 0 for /clocks/ahb@01c20054 > > [ 0.000000] Failed to enable critical clock cpu > > [ 0.000000] Failed to enable critical clock pll5_ddr > > [ 0.000000] Failed to enable critical clock ahb_sdram > > [ 0.000000] Architected cp15 timer(s) running at 24.00MHz (virt). > > Ok. So it seems we need to come up with some solution to the > "critical clocks" problem that doesn't require the individual > clock drivers to call clk_prepare_enable(). I'm getting more and more unsure if we can really handle the complexity we get by allowing to register orphaned clocks. On one hand we can't handle the orphaned clocks properly when we do a clk_prepare/enable on them, on the other hand we run into trouble when we forbid to prepare/enable them. The fact that clocks can become orphans by reparenting them makes it even more complicated. Maybe allowing orphans is something that has to be revisited. Sascha -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | -- 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/