From: Alex Deucher <alexander.deucher@amd.com>
Date: Thu, 19 Apr 2018 13:56:41 -0500
Subject: drm/amdgpu/pm: document power_dpm_state
Git-commit: ca8d40ca194dfb573e59a5e42b88da83e63a6630
Patch-mainline: v4.18-rc1
References: FATE#326289 FATE#326079 FATE#326049 FATE#322398 FATE#326166

This is a legacy file and is only provided for
backwards compatibility.

Acked-by: Felix Kuehling <Felix.Kuehling@amd.com>
Reviewed-by: Huang Rui <ray.huang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c |   31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)

--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c
@@ -75,6 +75,37 @@ void amdgpu_pm_acpi_event_handler(struct
 	}
 }
 
+/**
+ * DOC: power_dpm_state
+ *
+ * This is a legacy interface and is only provided for backwards compatibility.
+ * The amdgpu driver provides a sysfs API for adjusting certain power
+ * related parameters.  The file power_dpm_state is used for this.
+ * It accepts the following arguments:
+ * - battery
+ * - balanced
+ * - performance
+ *
+ * battery
+ *
+ * On older GPUs, the vbios provided a special power state for battery
+ * operation.  Selecting battery switched to this state.  This is no
+ * longer provided on newer GPUs so the option does nothing in that case.
+ *
+ * balanced
+ *
+ * On older GPUs, the vbios provided a special power state for balanced
+ * operation.  Selecting balanced switched to this state.  This is no
+ * longer provided on newer GPUs so the option does nothing in that case.
+ *
+ * performance
+ *
+ * On older GPUs, the vbios provided a special power state for performance
+ * operation.  Selecting performance switched to this state.  This is no
+ * longer provided on newer GPUs so the option does nothing in that case.
+ *
+ */
+
 static ssize_t amdgpu_get_dpm_state(struct device *dev,
 				    struct device_attribute *attr,
 				    char *buf)