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All uploaded PM data from non-dom0 CPUs takes the info from vCPU 0 and changing only the acpi_id. For processors which P-state coordination type is HW_ALL (0xFD) it is OK to upload bogus P-state dependency information (_PSD), because Xen will ignore any cpufreq domains created for past CPUs. Albeit for platforms which expose coordination types as SW_ANY or SW_ALL, this will have some unintended side effects. Effectively, it will look at the P-state domain existence and *if it already exists* it will skip the acpi-cpufreq initialization and thus inherit the policy from the first CPU in the cpufreq domain. This will finally lead to the original cpu not changing target freq to P0 other than the first in the domain. Which will make turbo boost not getting enabled (e.g. for 'performance' governor) for all cpus. This patch fixes that, by also evaluating _PSD when we enumerate all ACPI processors and thus always uploading the correct info to Xen. We export acpi_processor_get_psd() for that this purpose, but change signature to not assume an existent of acpi_processor given that ACPI isn't creating an acpi_processor for non-dom0 CPUs. Signed-off-by: Joao Martins <joao.m.martins@oracle.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
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.