From: Lijo Lazar Date: Mon, 13 May 2024 06:34:50 +0000 (+0530) Subject: Documentation/amdgpu: Add PM policy documentation X-Git-Tag: v6.11-rc1~141^2~25^2~128 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=f88e570d4b1fb97dc4d1b27235757cedec7707d3;p=thirdparty%2Fkernel%2Flinux.git Documentation/amdgpu: Add PM policy documentation Add documentation about the newly added pm_policy node in sysfs. Signed-off-by: Lijo Lazar Acked-by: Alex Deucher Reviewed-by: Asad Kamal Signed-off-by: Alex Deucher --- diff --git a/Documentation/gpu/amdgpu/thermal.rst b/Documentation/gpu/amdgpu/thermal.rst index 2f6166f81e6a6..6d942b5c58f05 100644 --- a/Documentation/gpu/amdgpu/thermal.rst +++ b/Documentation/gpu/amdgpu/thermal.rst @@ -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 --------------- diff --git a/drivers/gpu/drm/amd/pm/amdgpu_pm.c b/drivers/gpu/drm/amd/pm/amdgpu_pm.c index 125fd1a25351b..d5d6ab484e5ad 100644 --- a/drivers/gpu/drm/amd/pm/amdgpu_pm.c +++ b/drivers/gpu/drm/amd/pm/amdgpu_pm.c @@ -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/ + * + * 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 > /sys/bus/pci/devices/.../pm_policy/" + * + * 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)