Re: [PATCH] PM / Domains: defer dev_pm_domain_set() until genpd->attach_dev succeeds if present

From	Kevin Hilman <khilman@baylibre.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH] PM / Domains: defer dev_pm_domain_set() until genpd->attach_dev succeeds if present
Date	2017-07-11 21:00 +0200
Message-ID	<u28y6-5YV-37@gated-at.bofh.it> (permalink)
References	<tXM37-2wf-5@gated-at.bofh.it> <tZCM2-4Vk-7@gated-at.bofh.it>
Organization	BayLibre

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"Rafael J. Wysocki" <rafael@kernel.org> writes:

> On Thu, Jun 29, 2017 at 8:00 PM, Sudeep Holla <sudeep.holla@arm.com> wrote:
>> If the genpd->attach_dev or genpd->power_on fails, genpd_dev_pm_attach
>> may return -EPROBE_DEFER initially. However genpd_alloc_dev_data sets
>> the PM domain for the device unconditionally.
>>
>> When subsequent attempts are made to call genpd_dev_pm_attach, it may
>> return -EEXISTS checking dev->pm_domain without re-attempting to call
>> attach_dev or power_on.
>>
>> platform_drv_probe then attempts to call drv->probe as the return value
>> -EEXIST != -EPROBE_DEFER, which may end up in a situation where the
>> device is accessed without it's power domain switched on.
>>
>> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
>> Cc: Kevin Hilman <khilman@kernel.org>
>> Cc: Ulf Hansson <ulf.hansson@linaro.org>
>> Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
>
> Ulf, this looks like a genuine fix to me, any comments?
>

This looks like the right fix to me.

Acked-by: Kevin Hilman <khilman@baylibre.com>

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Re: [PATCH] PM / Domains: defer dev_pm_domain_set() until  genpd->attach_dev succeeds if present "Rafael J. Wysocki" <rafael@kernel.org> - 2017-07-04 22:40 +0200
  Re: [PATCH] PM / Domains: defer dev_pm_domain_set() until genpd->attach_dev succeeds if present Kevin Hilman <khilman@baylibre.com> - 2017-07-11 21:00 +0200

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