linux-kernel - Re: [PATCH v3 0/2] clk: improve handling of orphan clocks

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Date:	Thu, 7 May 2015 17:27:22 -0700
From:	Kevin Hilman <khilman@...nel.org>
To:	Stephen Boyd <sboyd@...eaurora.org>
Cc:	Kevin Hilman <khilman@...nel.org>,
	Heiko Stübner <heiko@...ech.de>,
	Mike Turquette <mturquette@...aro.org>,
	Doug Anderson <dianders@...omium.org>,
	linux-clk@...r.kernel.org, lkml <linux-kernel@...r.kernel.org>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>,
	Boris Brezillon <boris.brezillon@...e-electrons.com>,
	Alex Elder <elder@...aro.org>,
	Alexandre Belloni <alexandre.belloni@...e-electrons.com>,
	Stephen Warren <swarren@...dotorg.org>,
	Max Filippov <jcmvbkbc@...il.com>,
	Sascha Hauer <kernel@...gutronix.de>,
	Zhangfei Gao <zhangfei.gao@...aro.org>,
	Santosh Shilimkar <ssantosh@...nel.org>,
	Chao Xie <chao.xie@...vell.com>,
	Jason Cooper <jason@...edaemon.net>,
	Stefan Wahren <stefan.wahren@...e.com>,
	Andrew Bresticker <abrestic@...omium.org>,
	Robert Jarzmik <robert.jarzmik@...e.fr>,
	Georgi Djakov <georgi.djakov@...aro.org>,
	Sylwester Nawrocki <s.nawrocki@...sung.com>,
	Geert Uytterhoeven <geert+renesas@...der.be>,
	Barry Song <baohua@...nel.org>,
	Dinh Nguyen <dinguyen@...nsource.altera.com>,
	Viresh Kumar <viresh.linux@...il.com>,
	Gabriel FERNANDEZ <gabriel.fernandez@...com>,
	Emilio López <emilio@...pez.com.ar>,
	Peter De Sc hrijver <pdeschrijver@...dia.com>,
	Tero Kristo <t-kristo@...com>,
	Ulf Hansson <ulf.hansson@...aro.org>,
	Pawel Moll <pawel.moll@....com>,
	Michal Simek <michal.simek@...inx.com>,
	Olof Johansson <olof@...om.net>,
	Tyler Baker <tyler.baker@...aro.org>,
	Maxime Ripard <maxime.ripard@...e-electrons.com>
Subject: Re: [PATCH v3 0/2] clk: improve handling of orphan clocks

On Thu, May 7, 2015 at 2:03 PM, Stephen Boyd <sboyd@...eaurora.org> wrote:
> On 05/07/15 08:17, Kevin Hilman wrote:
>> On Fri, May 1, 2015 at 4:40 PM, Stephen Boyd <sboyd@...eaurora.org> wrote:
>>> On 05/01/15 15:07, Heiko Stübner 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 <heiko@...ech.de>
>>>> Reviewed-by: Heiko Stuebner <heiko@...ech.de>
>>> 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.

> 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@...20054
[    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).

Kevin
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