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[ Upstream commit 5241ab40f6e742f8a1631f8826faf6dc6412b3b5 ] During system-wide PM, genpd relies on its PM callbacks to be invoked for all its attached devices, as to deal with powering off/on the PM domain. In other words, genpd is not compatible with the direct_complete path, if executed by the PM core for any of its attached devices. However, when genpd's ->prepare() callback invokes pm_generic_prepare(), it does not take into account that it may return 1. Instead it treats that as an error internally and expects the PM core to abort the prepare phase and roll back. This leads to genpd not properly powering on/off the PM domain, because its internal counters gets wrongly balanced. To fix the behaviour, allow drivers to return 1 from their ->prepare() callbacks, but let's return 0 from genpd's ->prepare() callback in such case, as that prevents the PM core from running the direct_complete path for the device. Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Sasha Levin <alexander.levin@verizon.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. 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.