Messages in this thread Patch in this message | | | From | Fenghua Yu <> | Subject | [PATCH v5 5/5] x86/umwait: Document umwait control sysfs interfaces | Date | Wed, 19 Jun 2019 18:33:58 -0700 |
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Since two new sysfs interface files are created for umwait control, add an ABI document entry for the files: /sys/devices/system/cpu/umwait_control/enable_c02 /sys/devices/system/cpu/umwait_control/max_time
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com> Reviewed-by: Ashok Raj <ashok.raj@intel.com> --- .../ABI/testing/sysfs-devices-system-cpu | 21 +++++++++++++++++++ 1 file changed, 21 insertions(+)
diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu index 1528239f69b2..d22cdadd3161 100644 --- a/Documentation/ABI/testing/sysfs-devices-system-cpu +++ b/Documentation/ABI/testing/sysfs-devices-system-cpu @@ -538,3 +538,24 @@ Description: Intel Energy and Performance Bias Hint (EPB) This attribute is present for all online CPUs supporting the Intel EPB feature. + +What: /sys/devices/system/cpu/umwait_control + /sys/devices/system/cpu/umwait_control/enable_c02 + /sys/devices/system/cpu/umwait_control/max_time +Date: May 2019 +Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org> +Description: Umwait control + + enable_c02: Read/write interface to control umwait C0.2 state + Read returns C0.2 state status: + 0: C0.2 is disabled + 1: C0.2 is enabled + + Write 'Yy1' or [oO][nN] for on to enable C0.2 state. + Write 'Nn0' or [oO][fF] for off to disable C0.2 state. + + max_time: Read/write interface to control umwait maximum time + in TSC-quanta that the CPU can reside in either C0.1 + or C0.2 state. The time is an unsigned 32-bit number. + Note that a value of zero means there is no limit. + Low order two bits must be zero. -- 2.19.1
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