[PATCH v2 3/4] Documentation/gpu: Document GFXOFF's count and residency

From: André Almeida
Date: Tue Jul 26 2022 - 14:23:30 EST


Add documentation explaining those two new files.

While here, add a note about the value type.

Signed-off-by: André Almeida <andrealmeid@xxxxxxxxxx>
---
Documentation/gpu/amdgpu/thermal.rst | 18 +++++++++++++++++-
1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/Documentation/gpu/amdgpu/thermal.rst b/Documentation/gpu/amdgpu/thermal.rst
index 997231b6adcf..5e27e4eb3959 100644
--- a/Documentation/gpu/amdgpu/thermal.rst
+++ b/Documentation/gpu/amdgpu/thermal.rst
@@ -72,7 +72,8 @@ 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:
+Userspace can interact with GFXOFF through a debugfs interface (all values in
+`uint32_t`, unless otherwise noted):

``amdgpu_gfxoff``
-----------------
@@ -104,3 +105,18 @@ Read it to check current GFXOFF's status of a GPU::
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.
+
+``amdgpu_gfxoff_count``
+-----------------------
+
+Read it to get the total GFXOFF entry count at the time of query since system
+power-up. The value is an `uint64_t` type, however, due to firmware limitations,
+it can currently overflow as an `uint32_t`. *Only supported in vangogh*
+
+``amdgpu_gfxoff_residency``
+---------------------------
+
+Write 1 to amdgpu_gfxoff_residency to start logging, and 0 to stop. Read it to
+get average GFXOFF residency % multiplied by 100 during the last logging
+interval. E.g. a value of 7854 means 78.54% of the time in the last logging
+interval the GPU was in GFXOFF mode. *Only supported in vangogh*
--
2.37.1