From: Ulf Hansson <ulf.hansson@linaro.org>
To: Saravana Kannan <saravanak@google.com>,
"Rafael J. Wysocki" <rjw@rjwysocki.net>,
Stephen Boyd <sboyd@kernel.org>
Cc: Rob Herring <robh@kernel.org>,
John Stultz <john.stultz@linaro.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Linux PM <linux-pm@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
DTML <devicetree@vger.kernel.org>
Subject: [RFD] drivers: base: A driver's ->sync_state() callback don't get called
Date: Tue, 31 Aug 2021 15:55:47 +0200 [thread overview]
Message-ID: <CAPDyKFo9Bxremkb1dDrr4OcXSpE0keVze94Cm=zrkOVxHHxBmQ@mail.gmail.com> (raw)
Hi Saravana, Rafael, Stephen,
I have observed an issue with a driver's ->sync_state() callback that
doesn't get called, even if consumers/supplier device links conditions
should have been satisfied. I have narrowed down the problem, but I am
not sure what is the best solution to fix it, hence I am turning to
you for some discussion/advice.
I have two test platform drivers, one that matches on the
"test,pm-domains-test" compatible string (this driver also has the
->sync_state() callback assigned) and another driver that matches on
"test,runtime-pm-test".
This is the relevant part in my DTS file:
pm_domain_test {
compatible = "test,pm-domains-test";
pdParent: power-domain-parent {
#power-domain-cells = <0>;
};
pdChild: power-domain-child {
#power-domain-cells = <0>;
power-domains = <&pdParent>;
};
};
soctest: soctest {
compatible = "simple-bus";
rpmtest0 {
compatible = "test,runtime-pm-test";
power-domains = <&pdParent>;
};
};
During boot the fw_devlinks are being created and their corresponding
links. With some debug enabled this shows some of the interesting
parts that are being printed to the log:
[ 0.041539] device: 'pm_domain_test': device_add
[ 0.041629] OF: Not linking pm_domain_test to pm_domain_test - is descendant
[ 0.041718] device: 'soctest': device_add
[ 0.041803] OF: Linking rpmtest0 (consumer) to pm_domain_test (supplier)
[ 0.041829] device: 'platform:pm_domain_test--platform:soctest': device_add
[ 0.041892] platform soctest: Linked as a sync state only consumer
to pm_domain_test
[ 0.041957] OF: create child: /soctest/rpmtest0
[ 0.041995] device: 'soctest:rpmtest0': device_add
[ 0.042072] device:
'platform:pm_domain_test--platform:soctest:rpmtest0': device_add
[ 0.042132] devices_kset: Moving soctest:rpmtest0 to end of list
[ 0.042141] platform soctest:rpmtest0: Linked as a consumer to pm_domain_test
The interesting thing here is the "sync state only" link that gets
created. I assume there are good reasons for creating this link, even
if I fail to understand exactly why.
In any case, the sync state only link never gets dropped, which I
assume is because there is no driver getting bound for the "soctest"
device (it has only the "simple-bus" compatible).
In other words, it doesn't matter that both the rpmtest0 and the
pm_domain_test devices are probed, thus satisfying the
supplier/consumer conditions, the ->sync_state() callback doesn't get
called anyway.
Can you perhaps help to point me in a direction of how to best fix this problem?
Kind regards
Ulf Hansson
next reply other threads:[~2021-08-31 13:56 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-31 13:55 Ulf Hansson [this message]
2021-08-31 16:59 ` [RFD] drivers: base: A driver's ->sync_state() callback don't get called Saravana Kannan
2021-08-31 22:46 ` Saravana Kannan
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