fix(audio): release instances without supported streams

Retain an audio function when at least one direction has a supported configuration, but release the tentative instance when neither direction does. Unsupported and MIDI-only functions no longer consume host slots or emit mount callbacks.

Signed-off-by: HiFiPHile <[email protected]>

2 files changed, 38 insertions, 11 deletions

diff --git a/src/class/audio/audio_host.c b/src/class/audio/audio_host.c
index 2aad4040e..c29db658c 100644
--- a/src/class/audio/audio_host.c
+++ b/src/class/audio/audio_host.c
@@ -798,7 +798,6 @@ uint16_t audioh_open(uint8_t rhport, uint8_t dev_addr, const tusb_desc_interface
 
   uint8_t usb_input_terminal_id = 0;
   uint8_t usb_output_source_id  = 0;
-  bool    found_as_interface    = false;
   // A Feature Unit may precede the USB terminal that identifies its stream.
   typedef struct {
     uint8_t id;
@@ -887,15 +886,14 @@ uint16_t audioh_open(uint8_t rhport, uint8_t dev_addr, const tusb_desc_interface
       break;
     }
 
-    found_as_interface = true;
     TU_LOG_DRV("  Found AS Interface %u (alt = %u)\r\n", desc_interface->bInterfaceNumber,
                desc_interface->bAlternateSetting);
     p_desc = audioh_parse_as(p_audio, desc_interface, p_desc, desc_end);
   }
 
-  // This AC interface belongs to MIDI or another Audio subclass. Release the
-  // tentative instance and let the next class driver claim the interface.
-  if (!found_as_interface) {
+  // Release the tentative instance when no supported stream configuration was
+  // collected, including MIDI-only and unsupported Audio functions.
+  if (p_audio->in_stream.config_count == 0 && p_audio->out_stream.config_count == 0) {
     audioh_stream_reset(&p_audio->in_stream);
     audioh_stream_reset(&p_audio->out_stream);
     p_audio->daddr        = 0;
diff --git a/test/unit-test/test/host/audio/test_audio_host.c b/test/unit-test/test/host/audio/test_audio_host.c
index b11d5a766..37b35dae8 100644
--- a/test/unit-test/test/host/audio/test_audio_host.c
+++ b/test/unit-test/test/host/audio/test_audio_host.c
@@ -346,6 +346,24 @@ static const uint8_t duplex_fus_before_usb_terminals[] = {
   TEST_UAC1_CS_DATA_EP,
 };
 
+static const uint8_t playback_with_unsupported_capture[] = {
+  TEST_UAC1_AC_HEADER_2,
+  TEST_UAC1_INPUT_TERM(PLAYBACK_INPUT_TERM, AUDIO_TERM_TYPE_USB_STREAMING, 2),
+  TEST_UAC1_OUTPUT_TERM(CAPTURE_OUTPUT_TERM, AUDIO_TERM_TYPE_USB_STREAMING, CAPTURE_INPUT_TERM),
+  TEST_UAC1_AS_ALT0,
+  TEST_UAC1_AS_INTERFACE(1, 1),
+  TEST_UAC1_AS_GENERAL(PLAYBACK_INPUT_TERM),
+  TEST_UAC1_FORMAT(2, 2, 16, 48000),
+  TEST_UAC1_DATA_EP(0x01, TUSB_ISO_EP_ATT_ADAPTIVE, 192, 1),
+  TEST_UAC1_CS_DATA_EP,
+  TEST_UAC1_AS_INTERFACE_NUM(AUDIO_AS_IN_ITF, 0, 0),
+  TEST_UAC1_AS_INTERFACE_NUM(AUDIO_AS_IN_ITF, 1, 1),
+  TEST_UAC1_AS_GENERAL(CAPTURE_OUTPUT_TERM),
+  TEST_UAC1_FORMAT(1, 2, 12, 48000),
+  TEST_UAC1_DATA_EP(0x81, TUSB_ISO_EP_ATT_ASYNCHRONOUS, 96, 1),
+  TEST_UAC1_CS_DATA_EP,
+};
+
 static const uint8_t playback_with_two_frequencies[] = {
   TEST_UAC1_AC_HEADER,
   TEST_UAC1_INPUT_TERM(PLAYBACK_INPUT_TERM, AUDIO_TERM_TYPE_USB_STREAMING, 2),
@@ -667,16 +685,27 @@ void test_audio_host_parses_discrete_frequencies_with_interval_greater_than_one(
   TEST_ASSERT_EQUAL_UINT32(48000, config.sample_rate);
 }
 
-void test_audio_host_rejects_sampling_frequency_range(void) {
-  open_descriptors(playback_with_frequency_range, sizeof(playback_with_frequency_range));
+void test_audio_host_keeps_supported_stream_when_other_as_format_is_unsupported(void) {
+  open_descriptors(playback_with_unsupported_capture, sizeof(playback_with_unsupported_capture));
 
-  TEST_ASSERT_EQUAL_UINT8(0, tuh_audio_stream_count(0));
+  TEST_ASSERT_EQUAL_UINT8(1, tuh_audio_stream_count(0));
+  TEST_ASSERT_EQUAL(TUH_AUDIO_STREAM_PLAYBACK, tuh_audio_stream_direction(0, 0));
 }
 
-void test_audio_host_rejects_overflowed_frame_size_for_large_channel_count(void) {
-  open_descriptors(capture_with_large_channel_count, sizeof(capture_with_large_channel_count));
+void test_audio_host_rejects_sampling_frequency_range_and_releases_instance(void) {
+  TEST_ASSERT_EQUAL_UINT16(0, audioh_open(0, AUDIO_DEV_ADDR, (const tusb_desc_interface_t *)playback_with_frequency_range,
+                                          sizeof(playback_with_frequency_range)));
+  TEST_ASSERT_EQUAL_UINT8(0, tuh_audio_get_dev_addr(0));
 
-  TEST_ASSERT_EQUAL_UINT8(0, tuh_audio_stream_count(0));
+  open_descriptors(playback_with_explicit_feedback, sizeof(playback_with_explicit_feedback));
+  TEST_ASSERT_EQUAL_UINT8(1, tuh_audio_stream_count(0));
+}
+
+void test_audio_host_rejects_overflowed_frame_size_for_large_channel_count(void) {
+  TEST_ASSERT_EQUAL_UINT16(0, audioh_open(0, AUDIO_DEV_ADDR,
+                                          (const tusb_desc_interface_t *)capture_with_large_channel_count,
+                                          sizeof(capture_with_large_channel_count)));
+  TEST_ASSERT_EQUAL_UINT8(0, tuh_audio_get_dev_addr(0));
 }
 
 void test_audio_host_uses_cs_endpoint_declared_before_data_endpoint_on_start(void) {