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Documentation/amdgpu: Add PM policy documentation

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Add documentation about the newly added pm_policy node in sysfs.

Signed-off-by: Lijo Lazar <lijo.lazar@amd.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Asad Kamal <asad.kamal@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
This commit is contained in:
Lijo Lazar 2024-05-13 12:04:50 +05:30 committed by Alex Deucher
parent 04806c1a21
commit f88e570d4b
2 changed files with 59 additions and 0 deletions
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6
Documentation/gpu/amdgpu/thermal.rst
View File

@ -49,6 +49,12 @@ pp_power_profile_mode
.. kernel-doc:: drivers/gpu/drm/amd/pm/amdgpu_pm.c
:doc: pp_power_profile_mode
pm_policy
---------------------
.. kernel-doc:: drivers/gpu/drm/amd/pm/amdgpu_pm.c
:doc: pm_policy
\*_busy_percent
---------------

53
drivers/gpu/drm/amd/pm/amdgpu_pm.c
View File

@ -2220,6 +2220,59 @@ struct amdgpu_pm_policy_attr {
enum pp_pm_policy id;
};
/**
* DOC: pm_policy
*
* Certain SOCs can support different power policies to optimize application
* performance. However, this policy is provided only at SOC level and not at a
* per-process level. This is useful especially when entire SOC is utilized for
* dedicated workload.
*
* The amdgpu driver provides a sysfs API for selecting the policy. Presently,
* only two types of policies are supported through this interface.
*
* Pstate Policy Selection - This is to select different Pstate profiles which
* decides clock/throttling preferences.
*
* XGMI PLPD Policy Selection - When multiple devices are connected over XGMI,
* this helps to select policy to be applied for per link power down.
*
* The list of available policies and policy levels vary between SOCs. They can
* be viewed under pm_policy node directory. If SOC doesn't support any policy,
* this node won't be available. The different policies supported will be
* available as separate nodes under pm_policy.
*
* cat /sys/bus/pci/devices/.../pm_policy/<policy_type>
*
* Reading the policy file shows the different levels supported. The level which
* is applied presently is denoted by * (asterisk). E.g.,
*
* .. code-block:: console
*
* cat /sys/bus/pci/devices/.../pm_policy/soc_pstate
* 0 : soc_pstate_default
* 1 : soc_pstate_0
* 2 : soc_pstate_1*
* 3 : soc_pstate_2
*
* cat /sys/bus/pci/devices/.../pm_policy/xgmi_plpd
* 0 : plpd_disallow
* 1 : plpd_default
* 2 : plpd_optimized*
*
* To apply a specific policy
*
* "echo <level> > /sys/bus/pci/devices/.../pm_policy/<policy_type>"
*
* For the levels listed in the example above, to select "plpd_optimized" for
* XGMI and "soc_pstate_2" for soc pstate policy -
*
* .. code-block:: console
*
* echo "2" > /sys/bus/pci/devices/.../pm_policy/xgmi_plpd
* echo "3" > /sys/bus/pci/devices/.../pm_policy/soc_pstate
*
*/
static ssize_t amdgpu_get_pm_policy_attr(struct device *dev,
struct device_attribute *attr,
char *buf)