diff --git a/src/include/sof/trace/trace.h b/src/include/sof/trace/trace.h
index d0c2df28a..437dbd388 100644
--- a/src/include/sof/trace/trace.h
+++ b/src/include/sof/trace/trace.h
@@ -161,7 +161,7 @@ int trace_filter_update(const struct trace_filter *elem);
 /** The start of this linker output MUST match the 'ldc_entry_header'
  *  struct defined in the logger program running in user space.
  */
-#define _DECLARE_LOG_ENTRY(lvl, format, comp_class, params)	\
+#define _DECLARE_LOG_ENTRY(lvl, format, comp_class, n_params)	\
 	__section(".static_log." #lvl)				\
 	static const struct {					\
 		uint32_t level;					\
@@ -175,7 +175,7 @@ int trace_filter_update(const struct trace_filter *elem);
 	} log_entry = {						\
 		lvl,						\
 		comp_class,					\
-		params,						\
+		n_params,						\
 		__LINE__,					\
 		sizeof(RELATIVE_FILE),				\
 		sizeof(format),					\
@@ -306,10 +306,14 @@ static inline int trace_filter_update(const struct trace_filter *filter)
 
 #endif /* CONFIG_TRACEE, CONFIG_TRACE */
 
-
-#define _TRACE_INV_CLASS	TRACE_CLASS_DEPRECATED
+/** Default value when there is no specific pipeline, dev, dai, etc. */
 #define _TRACE_INV_ID		-1
 
+/** This has been replaced in commits 6ce635aa82 and earlier by the
+ * DECLARE_TR_CTX, tr_ctx and component UUID system below
+ */
+#define _TRACE_INV_CLASS	TRACE_CLASS_DEPRECATED
+
 /**
  * Trace context.
  */
diff --git a/src/trace/dma-trace.c b/src/trace/dma-trace.c
index efabc75c0..1949022e7 100644
--- a/src/trace/dma-trace.c
+++ b/src/trace/dma-trace.c
@@ -120,6 +120,10 @@ out:
 	return SOF_TASK_STATE_RESCHEDULE;
 }
 
+/** Do this early so we can log at initialization time even before the
+ * DMA runs. The rest happens later in dma_trace_init_complete() and
+ * dma_trace_enable()
+ */
 int dma_trace_init_early(struct sof *sof)
 {
 	sof->dmat = rzalloc(SOF_MEM_ZONE_SYS_SHARED, 0, SOF_MEM_CAPS_RAM, sizeof(*sof->dmat));
@@ -135,6 +139,7 @@ int dma_trace_init_early(struct sof *sof)
 	return 0;
 }
 
+/** Run after dma_trace_init_early() and before dma_trace_enable() */
 int dma_trace_init_complete(struct dma_trace_data *d)
 {
 	int ret = 0;
@@ -317,6 +322,9 @@ static int dma_trace_get_avail_data(struct dma_trace_data *d,
 
 #endif  /* CONFIG_DMA_GW */
 
+/** Invoked remotely by SOF_IPC_TRACE_DMA_PARAMS* Depends on
+ * dma_trace_init_complete()
+ */
 int dma_trace_enable(struct dma_trace_data *d)
 {
 	int err;