drm/i915: Drop the CONTEXT_CLONE API (v2)

This API allows one context to grab bits out of another context upon
creation.  It can be used as a short-cut for setparam(getparam()) for
things like I915_CONTEXT_PARAM_VM.  However, it's never been used by any
real userspace.  It's used by a few IGT tests and that's it.  Since it
doesn't add any real value (most of the stuff you can CLONE you can copy
in other ways), drop it.

There is one thing that this API allows you to clone which you cannot
clone via getparam/setparam: timelines.  However, timelines are an
implementation detail of i915 and not really something that needs to be
exposed to userspace.  Also, sharing timelines between contexts isn't
obviously useful and supporting it has the potential to complicate i915
internally.  It also doesn't add any functionality that the client can't
get in other ways.  If a client really wants a shared timeline, they can
use a syncobj and set it as an in and out fence on every submit.

v2 (Jason Ekstrand):
 - More detailed commit message

Signed-off-by: Jason Ekstrand <jason@jlekstrand.net>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210708154835.528166-7-jason@jlekstrand.net

1 files changed, 3 insertions, 13 deletions

diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
index 79dcafaf476e..e334a8b14ef2 100644
--- a/include/uapi/drm/i915_drm.h
+++ b/include/uapi/drm/i915_drm.h
@@ -2006,20 +2006,10 @@ struct drm_i915_gem_context_create_ext_setparam {
 	struct drm_i915_gem_context_param param;
 };
 
-struct drm_i915_gem_context_create_ext_clone {
+/* This API has been removed.  On the off chance someone somewhere has
+ * attempted to use it, never re-use this extension number.
+ */
 #define I915_CONTEXT_CREATE_EXT_CLONE 1
-	struct i915_user_extension base;
-	__u32 clone_id;
-	__u32 flags;
-#define I915_CONTEXT_CLONE_ENGINES	(1u << 0)
-#define I915_CONTEXT_CLONE_FLAGS	(1u << 1)
-#define I915_CONTEXT_CLONE_SCHEDATTR	(1u << 2)
-#define I915_CONTEXT_CLONE_SSEU		(1u << 3)
-#define I915_CONTEXT_CLONE_TIMELINE	(1u << 4)
-#define I915_CONTEXT_CLONE_VM		(1u << 5)
-#define I915_CONTEXT_CLONE_UNKNOWN -(I915_CONTEXT_CLONE_VM << 1)
-	__u64 rsvd;
-};
 
 struct drm_i915_gem_context_destroy {
 	__u32 ctx_id;