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e8195f0630
Currently, if power.no_callbacks is set, device_prepare() will also set
power.direct_complete for the device. If power.direct_complete is set
in device_resume(), the clearing of power.is_prepared will be skipped
and if new children appear under the device at that point, a warning
will be printed.
After commit (f76b168b6f PM: Rename dev_pm_info.in_suspend to
is_prepared), power.is_prepared is generally cleared in device_resume()
before invoking the resume callback for the device which allows that
callback to add new children without triggering the warning, but this
does not happen for devices with power.direct_complete set.
This problem is visible in USB where usb_set_interface() can be called
before device_complete() clears power.is_prepared for interface devices
and since ep devices are added then, the warning is printed:
usb 1-1: reset high-speed USB device number 3 using ci_hdrc
ep_81: PM: parent 1-1:1.1 should not be sleeping
PM: resume devices took 0.936 seconds
Since it is legitimate to add the ep devices at that point, the
warning above is not particularly useful, so get rid of it by
clearing power.is_prepared in device_resume() for devices with
power.direct_complete set if they have no PM callbacks, in which
case they need not actually resume for the new children to work.
Suggested-by: Rafael J. Wysocki <rafael@kernel.org>
Signed-off-by: Xu Yang <xu.yang_2@nxp.com>
Link: https://patch.msgid.link/20250224070049.3338646-1-xu.yang_2@nxp.com
[ rjw: New subject, changelog edits, rephrased new code comment ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.