multiband_drc: instantaneous enabled state switch on processing

In present multiband_drc design, the enabled state is determined by
the switch control while multiband_drc starts to process. If the
switch control toggles while processing, it will take effects on the
next time multiband_drc starts to process.

This commit makes change to let the enabled state update
instantaneously by the switch control toggle when multiband_drc is
processing.

Signed-off-by: Pin-chih Lin <johnylin@google.com>
(cherry picked from commit 8e8ff75)

Author: johnylin76

src/audio/multiband_drc/multiband_drc.c

@@ -126,6 +126,14 @@ static int multiband_drc_init_coef(struct processing_module *mod, int16_t nch, u
 	comp_info(dev, "multiband_drc_init_coef(), initializing %i-way crossover",
 		  config->num_bands);
 
+	/* Crossover: determine the split function */
+	cd->crossover_split = crossover_find_split_func(config->num_bands);
+	if (!cd->crossover_split) {
+		comp_err(dev, "multiband_drc_init_coef(), No crossover_split for band count(%i)",
+			 config->num_bands);
+		return -EINVAL;
+	}
+
 	/* Crossover: collect the coef array and assign it to every channel */
 	crossover = config->crossover_coef;
 	for (ch = 0; ch < nch; ch++) {
@@ -328,7 +336,10 @@ static int multiband_drc_process(struct processing_module *mod,
 		}
 	}
 
-	cd->multiband_drc_func(mod, source, sink, frames);
+	if (cd->process_enabled)
+		cd->multiband_drc_func(mod, source, sink, frames);
+	else
+		multiband_drc_default_pass(mod, source, sink, frames);
 
 	/* calc new free and available */
 	module_update_buffer_position(&input_buffers[0], &output_buffers[0], frames);
@@ -364,32 +375,18 @@ static int multiband_drc_prepare(struct processing_module *mod,
 	comp_dbg(dev, "multiband_drc_prepare(), source_format=%d, sink_format=%d",
 		 cd->source_format, cd->source_format);
 	cd->config = comp_get_data_blob(cd->model_handler, NULL, NULL);
-	if (cd->config && cd->process_enabled) {
+	if (cd->config) {
 		ret = multiband_drc_setup(mod, channels, rate);
 		if (ret < 0) {
 			comp_err(dev, "multiband_drc_prepare() error: multiband_drc_setup failed.");
 			return ret;
 		}
+	}
 
-		cd->multiband_drc_func = multiband_drc_find_proc_func(cd->source_format);
-		if (!cd->multiband_drc_func) {
-			comp_err(dev, "multiband_drc_prepare(), No proc func");
-			return -EINVAL;
-		}
-
-		cd->crossover_split = crossover_find_split_func(cd->config->num_bands);
-		if (!cd->crossover_split) {
-			comp_err(dev, "multiband_drc_prepare(), No crossover_split for band num %i",
-				 cd->config->num_bands);
-			return -EINVAL;
-		}
-	} else {
-		comp_info(dev, "multiband_drc_prepare(), DRC is in passthrough mode");
-		cd->multiband_drc_func = multiband_drc_find_proc_func_pass(cd->source_format);
-		if (!cd->multiband_drc_func) {
-			comp_err(dev, "multiband_drc_prepare(), No proc func passthrough");
-			return -EINVAL;
-		}
+	cd->multiband_drc_func = multiband_drc_find_proc_func(cd->source_format);
+	if (!cd->multiband_drc_func) {
+		comp_err(dev, "multiband_drc_prepare(), No proc func");
+		return -EINVAL;
 	}
 
 	return ret;

src/audio/multiband_drc/multiband_drc.h

@@ -54,6 +54,11 @@ extern const struct multiband_drc_proc_fnmap multiband_drc_proc_fnmap[];
 extern const struct multiband_drc_proc_fnmap multiband_drc_proc_fnmap_pass[];
 extern const size_t multiband_drc_proc_fncount;
 
+void multiband_drc_default_pass(const struct processing_module *mod,
+                                const struct audio_stream *source,
+                                struct audio_stream *sink,
+                                uint32_t frames);
+
 /**
  * \brief Returns Multiband DRC processing function.
  */

src/audio/multiband_drc/multiband_drc_generic.c

@@ -11,10 +11,10 @@
 #include "multiband_drc.h"
 #include "../drc/drc_algorithm.h"
 
-static void multiband_drc_default_pass(const struct processing_module *mod,
-				       const struct audio_stream *source,
-				       struct audio_stream *sink,
-				       uint32_t frames)
+void multiband_drc_default_pass(const struct processing_module *mod,
+				const struct audio_stream *source,
+				struct audio_stream *sink,
+				uint32_t frames)
 {
 	audio_stream_copy(source, 0, sink, 0, audio_stream_get_channels(source) * frames);
 }