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Alex Elder says: ==================== net: ipa: kill off ipa_clock_get() This series replaces the remaining uses of ipa_clock_get() with calls to pm_runtime_get_sync() instead. It replaces all calls to ipa_clock_put() with calls to pm_runtime_put(). This completes the preparation for enabling automated suspend under the control of the power management core code. The next patch (in an upcoming series) enables that. Then the "ipa_clock" files and symbols will switch to using an "ipa_power" naming convention instead. Additional info It is possible for pm_runtime_get_sync() to return an error. There are really three cases, identified by return value: - 1, meaning power was already active - 0, meaning power was not previously active, but is now - EACCES, meaning runtime PM is disabled One additional case is EINVAL, meaning a previous suspend or resume (or idle) call returned an error. But we have always assumed this won't happen (we previously didn't even check for an error). But because we use pm_runtime_force_suspend() to implement system suspend, there's a chance we'd get an EACCES error (the first thing that function does is disable runtime suspend). Individual patches explain what happens in that case, but generally we just accept that it could be an unlikely problem (occurring only at startup time). Similarly, pm_runtime_put() could return an error. There too, we ignore EINVAL, assuming the IPA suspend and resume operations won't produce an error. EBUSY and EPERM are not applicable, EAGAIN is not expected (and harmless). We should never get EACCES (runtime suspend disabled), because pm_runtime_put() calls match prior pm_runtime_get_sync() calls, and a system suspend will not be started while a runtime suspend or resume is underway. In summary, the value returned from pm_runtime_put() is not meaningful, so we explicitly ignore it. ==================== Signed-off-by: David S. Miller <davem@davemloft.net> |
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| README | ||
README
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.