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authorChangbin Du <changbin.du@gmail.com>2019-04-25 01:53:04 +0800
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2019-04-25 23:07:20 +0200
commit4887954cac779abe38d3ba6446dec341ccca04ea (patch)
treeab9ec6c57324c628188cad0a2911a50fd28ffd43 /Documentation/acpi
parent3e57460f007c86476c376a08e31da441cae0b195 (diff)
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Documentation: ACPI: move lpit.txt to firmware-guide/acpi and convert to reST
This converts the plain text documentation to reStructuredText format and adds it to Sphinx TOC tree. No essential content change. Signed-off-by: Changbin Du <changbin.du@gmail.com> Reviewed-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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diff --git a/Documentation/acpi/lpit.txt b/Documentation/acpi/lpit.txt
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-To enumerate platform Low Power Idle states, Intel platforms are using
-“Low Power Idle Table” (LPIT). More details about this table can be
-downloaded from:
-http://www.uefi.org/sites/default/files/resources/Intel_ACPI_Low_Power_S0_Idle.pdf
-
-Residencies for each low power state can be read via FFH
-(Function fixed hardware) or a memory mapped interface.
-
-On platforms supporting S0ix sleep states, there can be two types of
-residencies:
-- CPU PKG C10 (Read via FFH interface)
-- Platform Controller Hub (PCH) SLP_S0 (Read via memory mapped interface)
-
-The following attributes are added dynamically to the cpuidle
-sysfs attribute group:
- /sys/devices/system/cpu/cpuidle/low_power_idle_cpu_residency_us
- /sys/devices/system/cpu/cpuidle/low_power_idle_system_residency_us
-
-The "low_power_idle_cpu_residency_us" attribute shows time spent
-by the CPU package in PKG C10
-
-The "low_power_idle_system_residency_us" attribute shows SLP_S0
-residency, or system time spent with the SLP_S0# signal asserted.
-This is the lowest possible system power state, achieved only when CPU is in
-PKG C10 and all functional blocks in PCH are in a low power state.