diff --git a/src/process.c b/src/process.c
index 08cb810ec13..5db56692fe1 100644
--- a/src/process.c
+++ b/src/process.c
@@ -6112,6 +6112,11 @@ read_and_dispose_of_process_output (struct Lisp_Process *p, char *chars,
 				    ssize_t nbytes,
 				    struct coding_system *coding);
 
+static void
+read_and_insert_process_output (struct Lisp_Process *p, char *buf,
+				    ssize_t nread,
+				struct coding_system *process_coding);
+
 /* Read pending output from the process channel,
    starting with our buffered-ahead character if we have one.
    Yield number of decoded characters read,
@@ -6227,7 +6232,10 @@ read_process_output (Lisp_Object proc, int channel)
      friends don't expect current-buffer to be changed from under them.  */
   record_unwind_current_buffer ();
 
-  read_and_dispose_of_process_output (p, chars, nbytes, coding);
+  if (p->filter == Qinternal_default_process_filter)
+    read_and_insert_process_output (p, chars, nbytes, coding);
+  else
+    read_and_dispose_of_process_output (p, chars, nbytes, coding);
 
   /* Handling the process output should not deactivate the mark.  */
   Vdeactivate_mark = odeactivate;
@@ -6236,6 +6244,46 @@ read_process_output (Lisp_Object proc, int channel)
   return nbytes;
 }
 
+static void read_and_insert_process_output (struct Lisp_Process *p, char *buf,
+				    ssize_t nread,
+				    struct coding_system *process_coding)
+{
+  if (!nread || NILP (p->buffer) || !BUFFER_LIVE_P (XBUFFER (p->buffer)))
+    ;
+  else if (NILP (BVAR (XBUFFER(p->buffer), enable_multibyte_characters))
+	   && ! CODING_MAY_REQUIRE_DECODING (process_coding))
+    {
+      insert_1_both (buf, nread, nread, 0, 0, 0);
+      signal_after_change (PT - nread, 0, nread);
+    }
+  else
+    {			/* We have to decode the input.  */
+      Lisp_Object curbuf;
+      int carryover = 0;
+      specpdl_ref count1 = SPECPDL_INDEX ();
+
+      XSETBUFFER (curbuf, current_buffer);
+      /* We cannot allow after-change-functions be run
+	 during decoding, because that might modify the
+	 buffer, while we rely on process_coding.produced to
+	 faithfully reflect inserted text until we
+	 TEMP_SET_PT_BOTH below.  */
+      specbind (Qinhibit_modification_hooks, Qt);
+      decode_coding_c_string (process_coding,
+			      (unsigned char *) buf, nread, curbuf);
+      unbind_to (count1, Qnil);
+
+      TEMP_SET_PT_BOTH (PT + process_coding->produced_char,
+			PT_BYTE + process_coding->produced);
+      signal_after_change (PT - process_coding->produced_char,
+			   0, process_coding->produced_char);
+      carryover = process_coding->carryover_bytes;
+      if (carryover > 0)
+	memcpy (buf, process_coding->carryover,
+		process_coding->carryover_bytes);
+    }
+}
+
 static void
 read_and_dispose_of_process_output (struct Lisp_Process *p, char *chars,
 				    ssize_t nbytes,