diff options
Diffstat (limited to 'drivers/gpu/drm/amd/pm/amdgpu_pm.c')
| -rw-r--r-- | drivers/gpu/drm/amd/pm/amdgpu_pm.c | 53 |
1 files changed, 53 insertions, 0 deletions
diff --git a/drivers/gpu/drm/amd/pm/amdgpu_pm.c b/drivers/gpu/drm/amd/pm/amdgpu_pm.c index 125fd1a25351..d5d6ab484e5a 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/<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) |