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Diffstat (limited to 'Documentation/gpu')
| -rw-r--r-- | Documentation/gpu/amdgpu/thermal.rst | 41 |
1 files changed, 41 insertions, 0 deletions
diff --git a/Documentation/gpu/amdgpu/thermal.rst b/Documentation/gpu/amdgpu/thermal.rst index 8aeb0186c9ef..997231b6adcf 100644 --- a/Documentation/gpu/amdgpu/thermal.rst +++ b/Documentation/gpu/amdgpu/thermal.rst @@ -63,3 +63,44 @@ gpu_metrics .. kernel-doc:: drivers/gpu/drm/amd/pm/amdgpu_pm.c :doc: gpu_metrics + +GFXOFF +====== + +GFXOFF is a feature found in most recent GPUs that saves power at runtime. The +card's RLC (RunList Controller) firmware powers off the gfx engine +dynamically when there is no workload on gfx or compute pipes. GFXOFF is on by +default on supported GPUs. + +Userspace can interact with GFXOFF through a debugfs interface: + +``amdgpu_gfxoff`` +----------------- + +Use it to enable/disable GFXOFF, and to check if it's current enabled/disabled:: + + $ xxd -l1 -p /sys/kernel/debug/dri/0/amdgpu_gfxoff + 01 + +- Write 0 to disable it, and 1 to enable it. +- Read 0 means it's disabled, 1 it's enabled. + +If it's enabled, that means that the GPU is free to enter into GFXOFF mode as +needed. Disabled means that it will never enter GFXOFF mode. + +``amdgpu_gfxoff_status`` +------------------------ + +Read it to check current GFXOFF's status of a GPU:: + + $ xxd -l1 -p /sys/kernel/debug/dri/0/amdgpu_gfxoff_status + 02 + +- 0: GPU is in GFXOFF state, the gfx engine is powered down. +- 1: Transition out of GFXOFF state +- 2: Not in GFXOFF state +- 3: Transition into GFXOFF state + +If GFXOFF is enabled, the value will be transitioning around [0, 3], always +getting into 0 when possible. When it's disabled, it's always at 2. Returns +``-EINVAL`` if it's not supported. |