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The users of the idle injection framework allow 100% idle injection. For example: thermal/cpuidle_cooling.c driver. When the ratio is set to 100%, the runtime_duration becomes zero. However, idle_inject_set_duration() in the idle injection framework silently ignores run_duration_us == 0 without any error (it is a void function). The caller will then assume that everything is fine and 100% idle is effective, but in reality the idle duration will not change. There are two options: - The caller may change their max state to 99% instead of 100% and document that 100% is not supported by the idle inject framework. - Add 100% idle support to the idle inject framework. Since there are other protections via RT throttling, this framework can allow 100% idle. The RT throttling will be activated at 95% idle by default. The caller disabling RT throttling and injecting 100% idle, should be aware that CPU can't be used at all. The idle inject timer is started for (run_duration_us + idle_duration_us) duration. Hence replace (run_duration_us && idle_duration_us) with (run_duration_us + idle_duration_us) in the function idle_inject_set_duration(). Also check for !(run_duration_us + idle_duration_us) to return -EINVAL in idle_inject_start(). Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org> [ rjw: Changelog edits ] 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 Restructured Text 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.