Date:   Wed, 28 Oct 2020 15:22:39 +0530
From:   Viresh Kumar <viresh.kumar@...aro.org>
To:     Geert Uytterhoeven <geert@...ux-m68k.org>
Cc:     Stephan Gerhold <stephan@...hold.net>,
        Ulf Hansson <ulf.hansson@...aro.org>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Liam Girdwood <lgirdwood@...il.com>,
        Mark Brown <broonie@...nel.org>,
        Linux PM list <linux-pm@...r.kernel.org>,
        Vincent Guittot <vincent.guittot@...aro.org>,
        Stephen Boyd <sboyd@...nel.org>, Nishanth Menon <nm@...com>,
        nks@...wful.org, Georgi Djakov <georgi.djakov@...aro.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Wolfram Sang <wsa@...-dreams.de>,
        Linux I2C <linux-i2c@...r.kernel.org>,
        Linux-Renesas <linux-renesas-soc@...r.kernel.org>
Subject: Re: [PATCH V2 2/2] cpufreq: dt: Refactor initialization to handle
 probe deferral properly

On 28-10-20, 10:49, Geert Uytterhoeven wrote:
> Hi Viresh,
> 
> On Wed, Oct 28, 2020 at 6:48 AM Viresh Kumar <viresh.kumar@...aro.org> wrote:
> > On 27-10-20, 17:29, Geert Uytterhoeven wrote:
> > > On plain v5.9, with #define DEBUG and a few extra debug prints
> > > added, I get:
> > >
> > >     cpufreq_dt: cpufreq_init:164: policy->cpu = 0
> > >     cpufreq_dt: cpufreq_init:165: policy->cpus = 0
> > >     cpufreq_dt: cpufreq_init:166: policy->related_cpus =
> > >     cpufreq_dt: cpufreq_init:167: policy->real_cpus =
> > >     cpu cpu0: dev_pm_opp_of_get_sharing_cpus: Couldn't find opp node.
> > >     of: dev_pm_opp_of_cpumask_add_table:1049
> > >     of: dev_pm_opp_of_cpumask_add_table:1054: cpu 0
> > >     cpu cpu0: dev_pm_opp_of_add_table:954
> > >     cpu cpu0: dev_pm_opp_of_add_table:956:
> > > dev_pm_opp_get_opp_table_indexed() returned (ptrval)
> > >     cpu cpu0: _of_add_opp_table_v1:891
> > >     cpu cpu0: _of_add_opp_table_v1:893: _find_opp_table() returned (ptrval)
> > >     cpu cpu0: _of_add_opp_table_v1:909: 6 entries
> > >     cpu cpu0: dev_pm_opp_get_opp_count:331
> > >     cpu cpu0: dev_pm_opp_get_opp_count:333: _find_opp_table() returned (ptrval)
> > >     cpu cpu0: dev_pm_opp_get_opp_count:342: _get_opp_count() returned 6
> > >     cpu cpu0: dev_pm_opp_get_opp_count:331
> > >     cpu cpu0: dev_pm_opp_get_opp_count:333: _find_opp_table() returned (ptrval)
> > >     cpu cpu0: dev_pm_opp_get_opp_count:342: _get_opp_count() returned 6
> > >     cpu cpu0: dev_pm_opp_get_opp_count:331
> > >     cpu cpu0: dev_pm_opp_get_opp_count:333: _find_opp_table() returned (ptrval)
> > >     cpu cpu0: dev_pm_opp_get_opp_count:342: _get_opp_count() returned 6
> > >     cpu cpu0: Couldn't find proper 'dynamic-power-coefficient' in DT
> > >     cpu cpu0: Couldn't register Energy Model -22
> > >
> > > This happens quite late in the boot sequence, long after cpu1 has been
> > > brought online.
> > > So it finds the v1 opp table for cpu0, which has 6 entries.
> > > The last two messages should be harmless, right?
> >
> > Yes.
> >
> > > So you say cpufreq is not working? How can I verify that?
> >
> > I said it because your earlier logs showed that we defered probed
> > again or the count was 0 and we failed. Something like that.
> >
> > Give output of this to verify if cpufreq is working or not:
> >
> > grep . /sys/devices/system/cpu/cpufreq/policy*/*
> >
> > This will be empty if there is no cpufreq.
> 
> /sys/devices/system/cpu/cpufreq/policy0/affected_cpus:0 1
> /sys/devices/system/cpu/cpufreq/policy0/cpuinfo_cur_freq:375000
> /sys/devices/system/cpu/cpufreq/policy0/cpuinfo_max_freq:1500000
> /sys/devices/system/cpu/cpufreq/policy0/cpuinfo_min_freq:375000
> /sys/devices/system/cpu/cpufreq/policy0/cpuinfo_transition_latency:300000
> /sys/devices/system/cpu/cpufreq/policy0/related_cpus:0 1
> /sys/devices/system/cpu/cpufreq/policy0/scaling_available_frequencies:375000
> 750000 937500 1125000 1312500 1500000
> /sys/devices/system/cpu/cpufreq/policy0/scaling_available_governors:conservative
> ondemand userspace powersave performance schedutil
> /sys/devices/system/cpu/cpufreq/policy0/scaling_cur_freq:375000
> /sys/devices/system/cpu/cpufreq/policy0/scaling_driver:cpufreq-dt
> /sys/devices/system/cpu/cpufreq/policy0/scaling_governor:schedutil
> /sys/devices/system/cpu/cpufreq/policy0/scaling_max_freq:1500000
> /sys/devices/system/cpu/cpufreq/policy0/scaling_min_freq:375000
> /sys/devices/system/cpu/cpufreq/policy0/scaling_setspeed:<unsupported>
> 
> So it works in v5.9, but not in v5.10-rc1.
> 
> Bisection says it was broken by commit 90d46d71cce279d8 ("opp: Handle
> multiple calls for same OPP table in _of_add_opp_table_v1()").
> 
> > >     cpu cpu0: dev_pm_opp_get_opp_count:331
> > >     cpu cpu0: dev_pm_opp_get_opp_count:333: _find_opp_table() returned (ptrval)
> > >     cpu cpu0: dev_pm_opp_get_opp_count:342: _get_opp_count() returned 0
> > >     cpu cpu0: OPP table can't be empty
> > >
> > > Wait, _get_opp_count() returns 0?
> >
> > Does this fix it for you as well ?
> >
> > https://lore.kernel.org/lkml/2c73ab54717ef358b118ea0cfb727b1427e7730a.1602648719.git.viresh.kumar@linaro.org/
> 
> Thanks, it does. I had arrived at the same conclusion after bisection.
> 
> > I didn't point you to this earlier as your logs said something else.
> 
> All my logs said _get_opp_count() returns 0.
> 
> > > During s2ram, v5.10-rc1, it redoes most of the above, incl. touching the
> > > PMIC, which it shouldn't due in this phase of system resume:
> > >
> > >     Disabling non-boot CPUs ...
> > >     Enabling non-boot CPUs ...
> > >     cpufreq_dt: cpufreq_init:112: policy->cpu = 1
> > >     cpufreq_dt: cpufreq_init:113: policy->cpus = 1
> > >     cpufreq_dt: cpufreq_init:114: policy->related_cpus =
> > >     cpufreq_dt: cpufreq_init:115: policy->real_cpus =
> > >     of: dev_pm_opp_of_cpumask_add_table:1075
> > >     of: dev_pm_opp_of_cpumask_add_table:1080: cpu 0
> > >     cpu cpu0: dev_pm_opp_of_add_table:980
> > >     cpu cpu0: dev_pm_opp_of_add_table:982:
> > > dev_pm_opp_get_opp_table_indexed() returned f680980b
> > >     cpu cpu0: _of_add_opp_table_v1:914
> > >     cpu cpu0: _of_add_opp_table_v1:916: _find_opp_table() returned a4afd426
> > >     cpu cpu0: _of_add_opp_table_v1:937: 6 entries
> > >     i2c-sh_mobile e60b0000.i2c: Transfer request timed out
> > >
> > > The i2c controller is suspended, this could go boom...
> > >
> > >     i2c-sh_mobile e60b0000.i2c: Transfer request timed out
> > >     i2c-sh_mobile e60b0000.i2c: Transfer request timed out
> > >     i2c-sh_mobile e60b0000.i2c: Transfer request timed out
> > >     i2c-sh_mobile e60b0000.i2c: Transfer request timed out
> > >     i2c-sh_mobile e60b0000.i2c: Transfer request timed out
> > >     of: dev_pm_opp_of_cpumask_add_table:1080: cpu 1
> > >     cpu cpu1: dev_pm_opp_of_add_table:980
> > >     cpu cpu1: dev_pm_opp_of_add_table:982:
> > > dev_pm_opp_get_opp_table_indexed() returned f680980b
> > >     cpu cpu1: _of_add_opp_table_v1:914
> > >     cpu cpu1: _of_add_opp_table_v1:916: _find_opp_table() returned 9087c76d
> > >     cpu cpu1: _of_add_opp_table_v1:937: 6 entries
> > >     i2c-sh_mobile e60b0000.i2c: Transfer request timed out
> > >     i2c-sh_mobile e60b0000.i2c: Transfer request timed out
> > >     i2c-sh_mobile e60b0000.i2c: Transfer request timed out
> > >     i2c-sh_mobile e60b0000.i2c: Transfer request timed out
> > >     i2c-sh_mobile e60b0000.i2c: Transfer request timed out
> > >     i2c-sh_mobile e60b0000.i2c: Transfer request timed out
> > >     cpu cpu0: dev_pm_opp_get_opp_count:331
> > >     cpu cpu0: dev_pm_opp_get_opp_count:333: _find_opp_table() returned f680980b
> > >     cpu cpu0: dev_pm_opp_get_opp_count:342: _get_opp_count() returned 0
> > >     cpu cpu0: OPP table can't be empty
> > >     CPU1 is up
> >
> > Lets make the normal boot work first and see about this later.
> 
> This is also fixed by your patch: the PMIC is no longer accessed while
> suspended.

Ah finally. Thanks, everything worked as expected :)

-- 
viresh

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