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Date: Fri, 16 Oct 2020 08:44:05 +0200
From: Geert Uytterhoeven <geert@...ux-m68k.org>
To: Viresh Kumar <viresh.kumar@...aro.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
Hi Viresh,
On Fri, Oct 16, 2020 at 7:03 AM Viresh Kumar <viresh.kumar@...aro.org> wrote:
> On 14-10-20, 18:40, Geert Uytterhoeven wrote:
> > On this platform (r8a7791-koelsch.dts), there is no opp table in DT.
I think you missed the clue above: this DTS does not have an opp-table
with operating-points-v2, but cpu0 does have the operating-points (v1)
property (note the latter is something I missed before).
> >
> > Before:
>
> I assume this means before this patchset came in..
Indeed.
> > boot:
> > cpufreq-dt cpufreq-dt: dt_cpufreq_probe:362
> > cpu cpu0: resources_available:95
> > cpu cpu0: resources_available:102: clk_get() returned z
> > cpu cpu0: resources_available:120:
> > dev_pm_opp_of_find_icc_paths() returned 0
> > cpu cpu0: resources_available:125: find_supply_name() returned cpu0
> > cpu cpu0: resources_available:132: regulator_get_optional()
> > returned -EPROBE_DEFER
> > cpu cpu0: cpu0 regulator not ready, retry
> > cpufreq-dt cpufreq-dt: dt_cpufreq_probe:371:
> > resources_available() returned -517
>
> we deferred probe once.
>
> > ...
> > cpufreq-dt cpufreq-dt: dt_cpufreq_probe:362
> > cpu cpu0: resources_available:95
> > cpu cpu0: resources_available:102: clk_get() returned z
> > cpu cpu0: resources_available:120:
> > dev_pm_opp_of_find_icc_paths() returned 0
> > cpu cpu0: resources_available:125: find_supply_name() returned cpu0
> > cpu cpu0: resources_available:132: regulator_get_optional()
> > returned (ptrval)
>
> found regulator next time.
>
> > cpufreq-dt cpufreq-dt: dt_cpufreq_probe:371:
> > resources_available() returned 0
> > cpufreq-dt cpufreq-dt: dt_cpufreq_probe:375
> > cpufreq_dt: cpufreq_init:162
> > cpu cpu0: cpufreq_init:170: clk_get() returned z
> > cpu cpu0: cpufreq_init:179: dev_pm_opp_of_get_sharing_cpus() returned -2
> > cpu cpu0: cpufreq_init:198: find_supply_name() returned cpu0
> > <i2c comm>
> > cpu cpu0: cpufreq_init:201: dev_pm_opp_set_regulators() returned (ptrval)
> > <i2c comm>
> > cpu cpu0: cpufreq_init:230: dev_pm_opp_of_cpumask_add_table() returned 0
> > cpu cpu0: cpufreq_init:239: dev_pm_opp_get_opp_count() returned 0
> > cpu cpu0: OPP table is not ready, deferring probe
>
> This failed, as we couldn't have deferred probe from cpufreq_init.
> Which means that cpufreq didn't work here.
No opp-table in DT.
Shouldn't it use operating-points v1 instead?
> > cpufreq_dt: cpufreq_init:162
> > cpu cpu1: cpufreq_init:170: clk_get() returned z
> > cpu cpu1: cpufreq_init:179: dev_pm_opp_of_get_sharing_cpus() returned -2
> > cpu cpu1: no regulator for cpu1
> > cpu cpu1: cpufreq_init:198: find_supply_name() returned (null)
> > cpu cpu1: cpufreq_init:230: dev_pm_opp_of_cpumask_add_table() returned 0
> > cpu cpu1: cpufreq_init:239: dev_pm_opp_get_opp_count() returned 0
> > cpu cpu1: OPP table is not ready, deferring probe
>
> Same for CPU1.
Note that only CPU0 has operating-points v1.
>
> >
> > s2ram:
> > cpufreq_dt: cpufreq_init:162
> > cpu cpu1: cpufreq_init:170: clk_get() returned z
> > cpu cpu1: cpufreq_init:179: dev_pm_opp_of_get_sharing_cpus() returned -2
> > cpu cpu1: no regulator for cpu1
> > cpu cpu1: cpufreq_init:198: find_supply_name() returned (null)
> > cpu cpu1: cpufreq_init:230: dev_pm_opp_of_cpumask_add_table() returned 0
> > cpu cpu1: cpufreq_init:239: dev_pm_opp_get_opp_count() returned 0
> > cpu cpu1: OPP table is not ready, deferring probe
>
> And same here.
>
> > CPU1 is up
> >
> > After:
> > boot:
> > cpufreq-dt cpufreq-dt: dt_cpufreq_probe:356
> > cpufreq_dt: dt_cpufreq_early_init:251
> > cpu cpu0: dt_cpufreq_early_init:256
> > cpu cpu0: dt_cpufreq_early_init:271: dev_pm_opp_get_opp_table()
> > returned (ptrval)
> > cpu cpu0: dt_cpufreq_early_init:284: find_supply_name() returned cpu0
> > cpu cpu0: dt_cpufreq_early_init:288: dev_pm_opp_set_regulators()
> > returned -EPROBE_DEFER
> > cpufreq-dt cpufreq-dt: dt_cpufreq_probe:360:
> > dt_cpufreq_early_init() returned -517
> > ...
> > cpufreq-dt cpufreq-dt: dt_cpufreq_probe:356
> > cpufreq_dt: dt_cpufreq_early_init:251
> > cpu cpu0: dt_cpufreq_early_init:256
> > cpu cpu0: dt_cpufreq_early_init:271: dev_pm_opp_get_opp_table()
> > returned (ptrval)
> > cpu cpu0: dt_cpufreq_early_init:284: find_supply_name() returned cpu0
> > cpu cpu0: dt_cpufreq_early_init:288: dev_pm_opp_set_regulators()
> > returned (ptrval)
> > cpu cpu0: dt_cpufreq_early_init:301:
> > dev_pm_opp_of_get_sharing_cpus() returned -2
> > cpufreq-dt cpufreq-dt: dt_cpufreq_probe:360:
> > dt_cpufreq_early_init() returned 0
> > cpufreq_dt: dt_cpufreq_early_init:251
> > cpufreq-dt cpufreq-dt: dt_cpufreq_probe:360:
> > dt_cpufreq_early_init() returned 0
> > cpufreq-dt cpufreq-dt: dt_cpufreq_probe:365
> > cpufreq_dt: cpufreq_init:114
> > cpu cpu0: cpufreq_init:124: clk_get() returned z
> > cpu cpu0: cpufreq_init:142: dev_pm_opp_of_cpumask_add_table() returned 0
> > cpu cpu0: cpufreq_init:151: dev_pm_opp_get_opp_count() returned 0
> > cpu cpu0: OPP table can't be empty
>
> Same issue here.
>
> > cpufreq_dt: cpufreq_init:114
> > cpu cpu0: cpufreq_init:124: clk_get() returned z
> > <i2c comm>
> > cpu cpu0: cpufreq_init:142: dev_pm_opp_of_cpumask_add_table() returned 0
> > cpu cpu0: cpufreq_init:151: dev_pm_opp_get_opp_count() returned 0
> >
> > s2ram:
> >
> > cpufreq_dt: cpufreq_init:114
> > cpu cpu0: cpufreq_init:124: clk_get() returned z
> > WARNING: CPU: 1 PID: 14 at drivers/i2c/i2c-core.h:54
> > __i2c_transfer+0x2d8/0x310
> > i2c i2c-6: Transfer while suspended
> > cpu cpu0: cpufreq_init:142: dev_pm_opp_of_cpumask_add_table() returned 0
> > cpu cpu0: cpufreq_init:151: dev_pm_opp_get_opp_count() returned 0
> > cpu cpu0: OPP table can't be empty
> > CPU1 is up
> >
> > I hope this helps.
>
> Unfortunately it raised more questions than what it answered :(
Before, it bailed out before talking to the regulator during s2ram,
After, it talks to the regulator before bailing out, triggering the WARN().
1. Why is it bailing out without an opp-table, as operating-points (v1)
is present?
2. Even in the presence of an opp-table, the code would talk to the
PMIC while the I2C controller is suspended.
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
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