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From: Sudeep Holla <sudeep.holla@arm.com>
To: Viresh Kumar <viresh.kumar@linaro.org>
Cc: ulf.hansson@linaro.org, "Rafael J. Wysocki" <rjw@rjwysocki.net>,
	Kevin Hilman <khilman@kernel.org>, Pavel Machek <pavel@ucw.cz>,
	Len Brown <len.brown@intel.com>,
	Sudeep Holla <sudeep.holla@arm.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Viresh Kumar <vireshk@kernel.org>, Nishanth Menon <nm@ti.com>,
	Stephen Boyd <sboyd@kernel.org>, Kukjin Kim <kgene@kernel.org>,
	Krzysztof Kozlowski <krzk@kernel.org>,
	linux-pm@vger.kernel.org,
	Vincent Guittot <vincent.guittot@linaro.org>,
	nks@flawful.org, georgi.djakov@linaro.org,
	Stephan Gerhold <stephan@gerhold.net>,
	linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	linux-samsung-soc@vger.kernel.org
Subject: Re: [PATCH V2 1/2] opp: Allow dev_pm_opp_get_opp_table() to return -EPROBE_DEFER
Date: Fri, 16 Oct 2020 12:12:22 +0100	[thread overview]
Message-ID: <20201016111222.lvakbmjhlrocpogt@bogus> (raw)
In-Reply-To: <20201016060021.sotk72u4hioctg7o@bogus>

On Fri, Oct 16, 2020 at 07:00:21AM +0100, Sudeep Holla wrote:
> On Fri, Oct 16, 2020 at 09:54:34AM +0530, Viresh Kumar wrote:
> > On 15-10-20, 19:05, Sudeep Holla wrote:
> > > OK, this breaks with SCMI which doesn't provide clocks but manage OPPs
> > > directly. Before this change clk_get(dev..) was allowed to fail and
> > > --EPROBE_DEFER was not an error.
> >
> > I think the change in itself is fine. We should be returning from
> > there if we get EPROBE_DEFER. The question is rather why are you
> > getting EPROBE_DEFER here ?
> >
>
> Ah OK, I didn't spend too much time, saw -EPROBE_DEFER, just reverted
> this patch and it worked. I need to check it in detail yet.
>

You confused me earlier. As I said there will be no clock provider
registered for SCMI CPU/Dev DVFS.
	opp_table->clk = clk_get(dev, NULL);
will always return -EPROBE_DEFER as there is no clock provider for dev.
But this change now propagates that error to caller of dev_pm_opp_add
which means we can't add opp to a device if there are no clock providers.
This breaks for DVFS which don't operate separately with clocks and
regulators.

--
Regards,
Sudeep

WARNING: multiple messages have this Message-ID (diff)
From: Sudeep Holla <sudeep.holla@arm.com>
To: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Nishanth Menon <nm@ti.com>, Len Brown <len.brown@intel.com>,
	ulf.hansson@linaro.org, linux-samsung-soc@vger.kernel.org,
	Vincent Guittot <vincent.guittot@linaro.org>,
	Stephan Gerhold <stephan@gerhold.net>,
	Kevin Hilman <khilman@kernel.org>,
	Stephen Boyd <sboyd@kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	linux-pm@vger.kernel.org, "Rafael J. Wysocki" <rjw@rjwysocki.net>,
	linux-kernel@vger.kernel.org,
	Krzysztof Kozlowski <krzk@kernel.org>,
	nks@flawful.org, Kukjin Kim <kgene@kernel.org>,
	Pavel Machek <pavel@ucw.cz>, Sudeep Holla <sudeep.holla@arm.com>,
	georgi.djakov@linaro.org, linux-arm-kernel@lists.infradead.org,
	Viresh Kumar <vireshk@kernel.org>
Subject: Re: [PATCH V2 1/2] opp: Allow dev_pm_opp_get_opp_table() to return -EPROBE_DEFER
Date: Fri, 16 Oct 2020 12:12:22 +0100	[thread overview]
Message-ID: <20201016111222.lvakbmjhlrocpogt@bogus> (raw)
In-Reply-To: <20201016060021.sotk72u4hioctg7o@bogus>

On Fri, Oct 16, 2020 at 07:00:21AM +0100, Sudeep Holla wrote:
> On Fri, Oct 16, 2020 at 09:54:34AM +0530, Viresh Kumar wrote:
> > On 15-10-20, 19:05, Sudeep Holla wrote:
> > > OK, this breaks with SCMI which doesn't provide clocks but manage OPPs
> > > directly. Before this change clk_get(dev..) was allowed to fail and
> > > --EPROBE_DEFER was not an error.
> >
> > I think the change in itself is fine. We should be returning from
> > there if we get EPROBE_DEFER. The question is rather why are you
> > getting EPROBE_DEFER here ?
> >
>
> Ah OK, I didn't spend too much time, saw -EPROBE_DEFER, just reverted
> this patch and it worked. I need to check it in detail yet.
>

You confused me earlier. As I said there will be no clock provider
registered for SCMI CPU/Dev DVFS.
	opp_table->clk = clk_get(dev, NULL);
will always return -EPROBE_DEFER as there is no clock provider for dev.
But this change now propagates that error to caller of dev_pm_opp_add
which means we can't add opp to a device if there are no clock providers.
This breaks for DVFS which don't operate separately with clocks and
regulators.

--
Regards,
Sudeep

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linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  reply	other threads:[~2020-10-16 11:12 UTC|newest]

Thread overview: 65+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-24  9:09 [PATCH V2 1/2] opp: Allow dev_pm_opp_get_opp_table() to return -EPROBE_DEFER Viresh Kumar
2020-08-24  9:09 ` Viresh Kumar
2020-08-24  9:09 ` [PATCH V2 2/2] cpufreq: dt: Refactor initialization to handle probe deferral properly Viresh Kumar
2020-08-24 14:25   ` kernel test robot
2020-08-24 14:25   ` [PATCH] cpufreq: dt: fix semicolon.cocci warnings kernel test robot
2020-08-25  4:29     ` Viresh Kumar
     [not found]   ` <CGME20200901085708eucas1p231ccacd7b41685ece92ee21e3b726f28@eucas1p2.samsung.com>
2020-09-01  8:57     ` [PATCH V2 2/2] cpufreq: dt: Refactor initialization to handle probe deferral properly Marek Szyprowski
2020-09-01  9:45       ` Viresh Kumar
2020-09-01 10:05         ` Marek Szyprowski
2020-09-01 10:12           ` Viresh Kumar
2020-10-13  9:47   ` Geert Uytterhoeven
2020-10-13  9:56     ` Viresh Kumar
2020-10-14 16:40       ` Geert Uytterhoeven
2020-10-16  5:03         ` Viresh Kumar
2020-10-16  6:44           ` Geert Uytterhoeven
2020-10-16  8:07             ` Viresh Kumar
2020-10-27 16:29               ` Geert Uytterhoeven
2020-10-28  5:48                 ` Viresh Kumar
2020-10-28  9:49                   ` Geert Uytterhoeven
2020-10-28  9:52                     ` Viresh Kumar
2020-08-24  9:17 ` [PATCH V2 1/2] opp: Allow dev_pm_opp_get_opp_table() to return -EPROBE_DEFER Krzysztof Kozlowski
2020-08-24  9:17   ` Krzysztof Kozlowski
2020-08-24 11:08 ` Ulf Hansson
2020-08-24 11:08   ` Ulf Hansson
2020-08-24 11:39 ` Stephan Gerhold
2020-08-24 11:39   ` Stephan Gerhold
2020-10-15 18:05 ` Sudeep Holla
2020-10-15 18:05   ` Sudeep Holla
2020-10-16  4:24   ` Viresh Kumar
2020-10-16  4:24     ` Viresh Kumar
2020-10-16  6:00     ` Sudeep Holla
2020-10-16  6:00       ` Sudeep Holla
2020-10-16 11:12       ` Sudeep Holla [this message]
2020-10-16 11:12         ` Sudeep Holla
2020-10-16 15:28         ` Stephan Gerhold
2020-10-16 15:28           ` Stephan Gerhold
2020-10-19  4:58         ` Viresh Kumar
2020-10-19  4:58           ` Viresh Kumar
2020-10-19  9:17           ` Sudeep Holla
2020-10-19  9:17             ` Sudeep Holla
2020-10-19  9:24             ` Viresh Kumar
2020-10-19  9:24               ` Viresh Kumar
2020-10-19 10:12               ` Sudeep Holla
2020-10-19 10:12                 ` Sudeep Holla
2020-10-19 10:35                 ` Viresh Kumar
2020-10-19 10:35                   ` Viresh Kumar
2020-10-19 14:10                   ` Sudeep Holla
2020-10-19 14:10                     ` Sudeep Holla
2020-10-20  5:05                     ` Viresh Kumar
2020-10-20  5:05                       ` Viresh Kumar
2020-10-20  5:54                       ` Viresh Kumar
2020-10-20  5:54                         ` Viresh Kumar
2020-10-20  9:37                         ` Sudeep Holla
2020-10-20  9:37                           ` Sudeep Holla
2020-10-20  9:41                           ` Viresh Kumar
2020-10-20  9:41                             ` Viresh Kumar
2020-10-20  9:52                             ` Sudeep Holla
2020-10-20  9:52                               ` Sudeep Holla
2020-10-20  9:59                               ` Viresh Kumar
2020-10-20  9:59                                 ` Viresh Kumar
2020-10-27 22:24 ` Guenter Roeck
2020-10-27 22:24   ` Guenter Roeck
2020-10-28  4:06   ` Viresh Kumar
2020-10-28  4:06     ` Viresh Kumar
2020-10-28 17:29     ` Guenter Roeck

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