diff --git a/src/core/operators/cross.ml b/src/core/operators/cross.ml
index 2313a75dd1..9a9eb6b508 100644
--- a/src/core/operators/cross.ml
+++ b/src/core/operators/cross.ml
@@ -116,7 +116,7 @@ class cross val_source ~duration_getter ~override_duration ~persist_override
 
     method private prepare_transition_source s =
       let s = (s :> source) in
-      s#get_ready ~dynamic:true [(self :> source)];
+      s#get_ready [(self :> source)];
       Clock.unify ~pos:self#pos source#clock s#clock;
       transition_source <- Some s
 
@@ -124,24 +124,20 @@ class cross val_source ~duration_getter ~override_duration ~persist_override
       match transition_source with
         | None -> ()
         | Some s ->
-            s#leave ~dynamic:true (self :> source);
+            s#leave (self :> source);
             transition_source <- None
 
     method! private wake_up a =
       self#reset_analysis;
       super#wake_up a;
-      source#get_ready ~dynamic:true [(self :> source)];
       source#get_ready [(self :> source)];
-      Lang.iter_sources
-        (fun s -> s#get_ready ~dynamic:true [(self :> source)])
-        transition
+      source#get_ready [(self :> source)];
+      Lang.iter_sources (fun s -> s#get_ready [(self :> source)]) transition
 
     method! private sleep =
       source#leave (self :> source);
-      s#leave ~dynamic:true (self :> source);
-      Lang.iter_sources
-        (fun s -> s#leave ~dynamic:true (self :> source))
-        transition;
+      s#leave (self :> source);
+      Lang.iter_sources (fun s -> s#leave (self :> source)) transition;
       self#cleanup_transition_source
 
     (* in main time *)
diff --git a/src/core/operators/dyn_op.ml b/src/core/operators/dyn_op.ml
index ad78490e4e..b3b63848a9 100644
--- a/src/core/operators/dyn_op.ml
+++ b/src/core/operators/dyn_op.ml
@@ -73,14 +73,12 @@ class dyn ~init ~track_sensitive ~infallible ~resurection_time f =
       Lang.iter_sources
         (fun s ->
           Typing.(s#frame_type <: self#frame_type);
-          s#get_ready ~dynamic:true activation)
+          s#get_ready activation)
         f;
       self#select
 
     method! private sleep =
-      Lang.iter_sources
-        (fun s -> s#leave ~dynamic:true (self :> Source.source))
-        f;
+      Lang.iter_sources (fun s -> s#leave (self :> Source.source)) f;
       self#unregister_source ~already_locked:false
 
     method private _is_ready ?frame () =
diff --git a/src/core/operators/switch.ml b/src/core/operators/switch.ml
index 99b998c03a..342480b295 100644
--- a/src/core/operators/switch.ml
+++ b/src/core/operators/switch.ml
@@ -97,19 +97,15 @@ class virtual switch ~name ~override_meta ~transition_length
       activation <- (self :> source) :: activator;
       List.iter
         (fun { transition; source = s; _ } ->
-          s#get_ready ~dynamic:true activation;
-          Lang.iter_sources
-            (fun s -> s#get_ready ~dynamic:true activation)
-            transition)
+          s#get_ready activation;
+          Lang.iter_sources (fun s -> s#get_ready activation) transition)
         cases
 
     method! private sleep =
       List.iter
         (fun { transition; source = s; _ } ->
-          s#leave ~dynamic:true (self :> source);
-          Lang.iter_sources
-            (fun s -> s#leave ~dynamic:true (self :> source))
-            transition)
+          s#leave (self :> source);
+          Lang.iter_sources (fun s -> s#leave (self :> source)) transition)
         cases;
       if self#is_selected_generated then
         (Option.get selected).effective_source#leave (self :> source)
diff --git a/src/core/source.ml b/src/core/source.ml
index 29b77ee11f..34b9168c42 100644
--- a/src/core/source.ml
+++ b/src/core/source.ml
@@ -446,28 +446,15 @@ class virtual operator ?pos ?(name = "src") sources =
       consistency of the delivered stream chunk.
 
       Before that a source P accesses another source S it must activate it. The
-      activation can be static, or dynamic. A static activation means that
-      P may pull data from S at any time. A dynamic activation means that P
-      won't use S directly but may at some point build a source which will
-      access S. This dynamic creation may occur in the middle of an output
-      round, which is why S needs to know in advance, since in some cases it
-      might have to enter caching mode from the beginning of the round in case
-      the dynamic activation occurs.
-
       An activation is identified by the path to the source which required it.
       It is possible that two identical activations are done, and they should
       not be treated as a single one.
 
-      In short, a source can avoid caching when: it has only one static
-      activation and all its dynamic activations are sub-paths of the static
-      one. When there is no static activation, there cannot be any access.
-
       It is assumed that all streaming is done in one thread for a given clock,
       so the activation management API is not thread-safe. *)
 
     val mutable caching = false
-    val mutable dynamic_activations : operator list list = []
-    val mutable static_activations : operator list list = []
+    val mutable activations : operator list list = []
 
     method private update_caching_mode =
       let string_of activations =
@@ -476,23 +463,14 @@ class virtual operator ?pos ?(name = "src") sources =
              (fun l -> String.concat ":" (List.map (fun s -> s#id) l))
              activations)
       in
-      self#log#debug "Activations changed: static=[%s], dynamic=[%s]."
-        (string_of static_activations)
-        (string_of dynamic_activations);
+      self#log#debug "Activations changed: static=[%s]." (string_of activations);
 
       (* Decide whether caching mode is needed, and why *)
       match
         if self#is_active then Some "active source"
         else (
-          match static_activations with
-            | [] -> None
-            | [s] ->
-                if
-                  List.exists
-                    (fun d -> not (Utils.prefix (List.rev d) (List.rev s)))
-                    dynamic_activations
-                then Some "possible dynamic activation"
-                else None
+          match activations with
+            | [] | _ :: [] -> None
             | _ -> Some "two static activations")
       with
         | None ->
@@ -524,16 +502,15 @@ class virtual operator ?pos ?(name = "src") sources =
        The current implementation makes it dangerous to call #get_ready from
        another thread than the Root one, as interleaving with #get is
        forbidden. *)
-    method get_ready ?(dynamic = false) (activation : operator list) =
+    method get_ready (activation : operator list) =
       self#content_type_computation_allowed;
       if log == source_log then self#create_log;
-      if static_activations = [] && dynamic_activations = [] then (
+      if activations = [] then (
         source_log#info "Source %s gets up with content type: %s." id
           (Frame.string_of_content_type self#content_type);
         self#wake_up activation;
         List.iter (fun fn -> fn ()) on_wake_up);
-      if dynamic then dynamic_activations <- activation :: dynamic_activations
-      else static_activations <- activation :: static_activations;
+      activations <- activation :: activations;
       self#update_caching_mode
 
     val mutable on_sleep = []
@@ -546,7 +523,7 @@ class virtual operator ?pos ?(name = "src") sources =
        The current implementation makes it dangerous to call #leave from
        another thread than the Root one, as interleaving with #get is
        forbidden. *)
-    method leave ?(failed_to_start = true) ?(dynamic = false) src =
+    method leave ?(failed_to_start = true) src =
       let rec remove acc = function
         | [] when failed_to_start -> []
         | [] ->
@@ -555,15 +532,14 @@ class virtual operator ?pos ?(name = "src") sources =
         | (s :: _) :: tl when s = src -> List.rev_append acc tl
         | h :: tl -> remove (h :: acc) tl
       in
-      if dynamic then dynamic_activations <- remove [] dynamic_activations
-      else static_activations <- remove [] static_activations;
+      activations <- remove [] activations;
       self#update_caching_mode;
-      if static_activations = [] && dynamic_activations = [] then (
+      if activations = [] then (
         source_log#info "Source %s gets down." id;
         self#sleep;
         List.iter (fun fn -> try fn () with _ -> ()) on_sleep)
 
-    method is_up = static_activations <> [] || dynamic_activations <> []
+    method is_up = activations <> []
 
     (** Two methods called for initialization and shutdown of the source *)
     method private wake_up activation =
@@ -571,12 +547,11 @@ class virtual operator ?pos ?(name = "src") sources =
       self#log#important "Content type is %s."
         (Frame.string_of_content_type self#content_type);
       let activation = (self :> operator) :: activation in
-      List.iter (fun s -> s#get_ready ?dynamic:None activation) sources
+      List.iter (fun s -> s#get_ready activation) sources
 
     method private sleep =
       List.iter
-        (fun s ->
-          s#leave ?failed_to_start:None ?dynamic:None (self :> operator))
+        (fun s -> s#leave ?failed_to_start:None (self :> operator))
         sources
 
     (** Streaming *)
diff --git a/src/core/source.mli b/src/core/source.mli
index a2b8ba95b2..76ec44b0e8 100644
--- a/src/core/source.mli
+++ b/src/core/source.mli
@@ -125,7 +125,7 @@ class virtual source :
        method private set_clock : unit
 
        (** The operator says to the source that he will ask it frames. It may be called multiple times. *)
-       method get_ready : ?dynamic:bool -> source list -> unit
+       method get_ready : source list -> unit
 
        (** Register a callback when wake_up is called. *)
        method on_wake_up : (unit -> unit) -> unit
@@ -137,7 +137,7 @@ class virtual source :
        method private wake_up : source list -> unit
 
        (** Opposite of [get_ready] : the operator no longer needs the source. it may be called multiple times. *)
-       method leave : ?failed_to_start:bool -> ?dynamic:bool -> source -> unit
+       method leave : ?failed_to_start:bool -> source -> unit
 
        (** Register a callback when sleep is called. *)
        method on_sleep : (unit -> unit) -> unit
diff --git a/src/core/tools/producer_consumer.ml b/src/core/tools/producer_consumer.ml
index b7958750ab..876d11cdcc 100644
--- a/src/core/tools/producer_consumer.ml
+++ b/src/core/tools/producer_consumer.ml
@@ -107,14 +107,13 @@ class producer ?pos ?create_known_clock ~check_self_sync ~consumers ~name () =
       List.iter
         (fun c ->
           c#set_producer_buffer self#buffer;
-          c#get_ready ?dynamic:None [(self :> Source.source)])
+          c#get_ready [(self :> Source.source)])
         consumers
 
     method! sleep =
       super#sleep;
       List.iter
-        (fun c ->
-          c#leave ?failed_to_start:None ?dynamic:None (self :> Source.source))
+        (fun c -> c#leave ?failed_to_start:None (self :> Source.source))
         consumers
 
     method private get_frame buf =