From: Marek Szyprowski <m.szyprowski@samsung.com>
To: Sudeep Holla <sudeep.holla@arm.com>
Cc: linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org,
linux-samsung-soc@vger.kernel.org,
Viresh Kumar <viresh.kumar@linaro.org>,
"Rafael J . Wysocki" <rjw@rjwysocki.net>,
Nishanth Menon <nm@ti.com>, Stephen Boyd <sboyd@kernel.org>,
Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>,
Dave Gerlach <d-gerlach@ti.com>, Wolfram Sang <wsa@the-dreams.de>
Subject: Re: [PATCH 0/2] cpufreq/opp: rework regulator initialization
Date: Fri, 8 Feb 2019 13:04:18 +0100 [thread overview]
Message-ID: <66b33c07-4970-b60a-d924-d4baba79c836@samsung.com> (raw)
In-Reply-To: <20190208115122.GA13043@e107155-lin>
Hi Sudeep,
On 2019-02-08 12:51, Sudeep Holla wrote:
> On Fri, Feb 08, 2019 at 12:47:06PM +0100, Marek Szyprowski wrote:
>> On 2019-02-08 12:00, Sudeep Holla wrote:
>>> On Thu, Feb 07, 2019 at 01:22:25PM +0100, Marek Szyprowski wrote:
>>>> Dear All,
>>>>
>>>> This is a scenario that triggers the above issue:
>>> [...]
>>>> 1. system disables non-boot cpu's at the end of system suspend procedure,
>>>> 2. this in turn deinitializes cpufreq drivers for the disabled cpus,
>>>> 3. early in the system resume procedure all cpus are got back to online
>>>> state,
>>>> 4. this in turn causes cpufreq to be initialized for the newly onlined
>>>> cpus,
>>>> 5. cpufreq-dt acquires all its resources (clocks, regulators) during
>>>> ->init() callback,
>>> This is strictly not just restricted to cpufreq-dt, but to any driver
>>> supporting multiple policies. So we need a generic fix not just
>>> cpufreq-dt specific.
>> Could you point which other driver needs similar fix? Here in cpufreq-dt
>> the problem was caused by using regulator api (indirectly) from
>> ->init(). All other drivers, which have regulators support, are for old,
>> obsolete, uni-processor systems, which don't have the problem of
>> secondary cpu suspend during system suspend/resume cycle.
>>
> scmi_cpufreq for instance. We can fix that in driver my moving to polling
> to get cpufreq_get_rate, but we support both polling and interrupt based.
> We may wait for remote processor interrupt in get_rate.
Frankly, I don't feel I know enough to touch this driver and I don't
think that this can even be fixed in a generic way in the cpufreq core.
Maybe a comment somewhere is needed that ->init() might be called during
early system resume with irqs off and driver is responsible for handling
such case until the proper resume?
Best regards
--
Marek Szyprowski, PhD
Samsung R&D Institute Poland
next prev parent reply other threads:[~2019-02-08 12:04 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20190207122255eucas1p1cdebed838c799eca46cce6a654a26187@eucas1p1.samsung.com>
2019-02-07 12:22 ` [PATCH 0/2] cpufreq/opp: rework regulator initialization Marek Szyprowski
[not found] ` <CGME20190207122255eucas1p1444023f01217a43cfb958fe0bd48ef4d@eucas1p1.samsung.com>
2019-02-07 12:22 ` [PATCH 1/2] cpufreq: dt/ti/opp: move regulators initialization to the drivers Marek Szyprowski
[not found] ` <CGME20190207122256eucas1p17e8742176bda911263d2d14d2797a886@eucas1p1.samsung.com>
2019-02-07 12:22 ` [PATCH 2/2] cpufreq: dt: rework resources initialization Marek Szyprowski
2019-02-08 1:26 ` kbuild test robot
2019-02-08 6:49 ` [PATCH 0/2] cpufreq/opp: rework regulator initialization Viresh Kumar
2019-02-08 8:12 ` Marek Szyprowski
2019-02-08 8:55 ` Viresh Kumar
2019-02-08 9:15 ` Marek Szyprowski
2019-02-08 9:23 ` Viresh Kumar
2019-02-08 10:02 ` Marek Szyprowski
2019-02-08 10:08 ` Rafael J. Wysocki
2019-02-08 10:18 ` Rafael J. Wysocki
2019-02-08 10:28 ` Viresh Kumar
2019-02-08 10:22 ` Rafael J. Wysocki
2019-02-08 10:31 ` Marek Szyprowski
2019-02-08 10:31 ` Viresh Kumar
2019-02-08 10:42 ` Rafael J. Wysocki
2019-02-08 10:52 ` Rafael J. Wysocki
2019-02-08 11:39 ` Sudeep Holla
2019-02-08 12:03 ` Rafael J. Wysocki
2019-02-08 12:09 ` Sudeep Holla
2019-02-08 12:23 ` Rafael J. Wysocki
2019-02-08 14:28 ` Sudeep Holla
2019-02-08 11:00 ` Sudeep Holla
2019-02-08 11:47 ` Marek Szyprowski
2019-02-08 11:51 ` Sudeep Holla
2019-02-08 12:04 ` Marek Szyprowski [this message]
2019-02-08 12:11 ` Rafael J. Wysocki
2019-02-08 12:16 ` Sudeep Holla
2019-02-08 17:41 ` Sudeep Holla
2019-02-11 8:47 ` Viresh Kumar
2019-02-11 14:08 ` Sudeep Holla
2019-02-11 8:44 ` Viresh Kumar
2019-02-11 9:52 ` Marek Szyprowski
2019-02-11 9:55 ` Viresh Kumar
2019-02-11 12:22 ` Marek Szyprowski
2019-02-12 5:08 ` Viresh Kumar
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