[PATCH] Documentation/gpu: Document the situation with unqualified drm-memory-

[Tvrtko Ursulin]

From: Tvrtko Ursulin <tvrtko.ursulin at igalia.com>

Currently it is not well defined what is drm-memory- compared to other
categories.

In practice the only driver which emits these keys is amdgpu and in them
exposes the total memory use (including shared).

Document that drm-memory- and drm-total-memory- are aliases to prevent any
confusion in the future.

While at it also clarify that the reserved sub-string 'memory' refers to
the memory region component.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin at igalia.com>
Cc: Alex Deucher <alexander.deucher at amd.com>
Cc: Christian König <christian.keonig at amd.com>
Cc: Rob Clark <robdclark at chromium.org>
---
 Documentation/gpu/drm-usage-stats.rst | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/Documentation/gpu/drm-usage-stats.rst b/Documentation/gpu/drm-usage-stats.rst
index 6dc299343b48..ef5c0a0aa477 100644
--- a/Documentation/gpu/drm-usage-stats.rst
+++ b/Documentation/gpu/drm-usage-stats.rst
@@ -128,7 +128,9 @@ Memory
 
 Each possible memory type which can be used to store buffer objects by the
 GPU in question shall be given a stable and unique name to be returned as the
-string here.  The name "memory" is reserved to refer to normal system memory.
+string here.
+
+The region name "memory" is reserved to refer to normal system memory.
 
 Value shall reflect the amount of storage currently consumed by the buffer
 objects belong to this client, in the respective memory region.
@@ -136,6 +138,9 @@ objects belong to this client, in the respective memory region.
 Default unit shall be bytes with optional unit specifiers of 'KiB' or 'MiB'
 indicating kibi- or mebi-bytes.
 
+This is an alias for drm-total-<region> and only one of the two should be
+present.
+
 - drm-shared-<region>: <uint> [KiB|MiB]
 
 The total size of buffers that are shared with another file (e.g., have more
@@ -145,6 +150,9 @@ than a single handle).
 
 The total size of buffers that including shared and private memory.
 
+This is an alias for drm-memory-<region> and only one of the two should be
+present.
+
 - drm-resident-<region>: <uint> [KiB|MiB]
 
 The total size of buffers that are resident in the specified region.
-- 
2.44.0