From: Perry Yuan <perry.yuan@amd.com>
To: <rafael.j.wysocki@intel.com>, <Mario.Limonciello@amd.com>,
<ray.huang@amd.com>, <viresh.kumar@linaro.org>
Cc: <Deepak.Sharma@amd.com>, <Nathan.Fontenot@amd.com>,
<Alexander.Deucher@amd.com>, <Shimmer.Huang@amd.com>,
<Xiaojian.Du@amd.com>, <Li.Meng@amd.com>, <wyes.karny@amd.com>,
<linux-pm@vger.kernel.org>, <linux-kernel@vger.kernel.org>
Subject: [PATCH v12 11/11] Documentation: amd-pstate: introduce new global sysfs attributes
Date: Tue, 31 Jan 2023 17:00:16 +0800 [thread overview]
Message-ID: <20230131090016.3970625-12-perry.yuan@amd.com> (raw)
In-Reply-To: <20230131090016.3970625-1-perry.yuan@amd.com>
The amd-pstate driver supports switching working modes at runtime.
Users can view and change modes by interacting with the "status" sysfs
attribute.
1) check driver mode:
$ cat /sys/devices/system/cpu/amd-pstate/status
2) switch mode:
`# echo "passive" | sudo tee /sys/devices/system/cpu/amd-pstate/status`
or
`# echo "active" | sudo tee /sys/devices/system/cpu/amd-pstate/status`
Acked-by: Huang Rui <ray.huang@amd.com>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Reviewed-by: Wyes Karny <wyes.karny@amd.com>
Tested-by: Wyes Karny <wyes.karny@amd.com>
Signed-off-by: Perry Yuan <perry.yuan@amd.com>
---
Documentation/admin-guide/pm/amd-pstate.rst | 29 +++++++++++++++++++++
1 file changed, 29 insertions(+)
diff --git a/Documentation/admin-guide/pm/amd-pstate.rst b/Documentation/admin-guide/pm/amd-pstate.rst
index b6aee69f564f..5304adf2fc2f 100644
--- a/Documentation/admin-guide/pm/amd-pstate.rst
+++ b/Documentation/admin-guide/pm/amd-pstate.rst
@@ -339,6 +339,35 @@ processor must provide at least nominal performance requested and go higher if c
operating conditions allow.
+User Space Interface in ``sysfs``
+=================================
+
+Global Attributes
+-----------------
+
+``amd-pstate`` exposes several global attributes (files) in ``sysfs`` to
+control its functionality at the system level. They are located in the
+``/sys/devices/system/cpu/amd-pstate/`` directory and affect all CPUs.
+
+``status``
+ Operation mode of the driver: "active", "passive" or "disable".
+
+ "active"
+ The driver is functional and in the ``active mode``
+
+ "passive"
+ The driver is functional and in the ``passive mode``
+
+ "disable"
+ The driver is unregistered and not functional now.
+
+ This attribute can be written to in order to change the driver's
+ operation mode or to unregister it. The string written to it must be
+ one of the possible values of it and, if successful, writing one of
+ these values to the sysfs file will cause the driver to switch over
+ to the operation mode represented by that string - or to be
+ unregistered in the "disable" case.
+
``cpupower`` tool support for ``amd-pstate``
===============================================
--
2.34.1
next prev parent reply other threads:[~2023-01-31 9:06 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-31 9:00 [PATCH v12 00/11] Implement AMD Pstate EPP Driver Perry Yuan
2023-01-31 9:00 ` [PATCH v12 01/11] ACPI: CPPC: Add AMD pstate energy performance preference cppc control Perry Yuan
2023-01-31 9:00 ` [PATCH v12 02/11] Documentation: amd-pstate: add EPP profiles introduction Perry Yuan
2023-01-31 9:00 ` [PATCH v12 03/11] cpufreq: amd-pstate: optimize driver working mode selection in amd_pstate_param() Perry Yuan
2023-01-31 9:00 ` [PATCH v12 04/11] cpufreq: amd-pstate: implement Pstate EPP support for the AMD processors Perry Yuan
2023-01-31 9:00 ` [PATCH v12 05/11] cpufreq: amd-pstate: implement amd pstate cpu online and offline callback Perry Yuan
2023-01-31 9:00 ` [PATCH v12 06/11] cpufreq: amd-pstate: implement suspend and resume callbacks Perry Yuan
2023-01-31 9:00 ` [PATCH v12 07/11] cpufreq: amd-pstate: add driver working mode switch support Perry Yuan
2023-01-31 9:00 ` [PATCH v12 08/11] Documentation: amd-pstate: add amd pstate driver mode introduction Perry Yuan
2023-01-31 9:00 ` [PATCH v12 09/11] Documentation: introduce amd pstate active mode kernel command line options Perry Yuan
2023-01-31 9:00 ` [PATCH v12 10/11] cpufreq: amd-pstate: convert sprintf with sysfs_emit() Perry Yuan
2023-01-31 9:00 ` Perry Yuan [this message]
2023-01-31 12:36 ` [PATCH v12 00/11] Implement AMD Pstate EPP Driver Muhammad Usama Anjum
2023-02-03 21:03 ` Rafael J. Wysocki
2023-02-06 2:57 ` Yuan, Perry
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