From 5acd4ee978d9fa1da9476c0338190e08c53ea2aa Mon Sep 17 00:00:00 2001
From: Woody Chow <woodychow@google.com>
Date: Tue, 12 Oct 2021 13:42:38 +0900
Subject: [PATCH] snd: Add debug prints and comments to virtio-snd (cras)

BUG=None
TEST=cargo test

Change-Id: Id4d0795f9001215dea07b8ff4edeee723782d7c0
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/3217344
Reviewed-by: Chirantan Ekbote <chirantan@chromium.org>
Reviewed-by: Chih-Yang Hsia <paulhsia@chromium.org>
Tested-by: kokoro <noreply+kokoro@google.com>
Commit-Queue: Woody Chow <woodychow@google.com>
---
 devices/src/virtio/snd/common.rs              |  8 ++++++++
 .../virtio/snd/cras_backend/async_funcs.rs    | 13 +++++++++++-
 devices/src/virtio/snd/cras_backend/mod.rs    | 20 +++++++++++++++++--
 3 files changed, 38 insertions(+), 3 deletions(-)

diff --git a/devices/src/virtio/snd/common.rs b/devices/src/virtio/snd/common.rs
index c7f06b6c43..0f734e9c20 100644
--- a/devices/src/virtio/snd/common.rs
+++ b/devices/src/virtio/snd/common.rs
@@ -102,3 +102,11 @@ pub fn get_virtio_snd_r_pcm_cmd_name(cmd_code: u32) -> &'static str {
         _ => unreachable!(),
     }
 }
+
+pub fn get_virtio_direction_name(dir: u8) -> &'static str {
+    match dir {
+        VIRTIO_SND_D_OUTPUT => "VIRTIO_SND_D_OUTPUT",
+        VIRTIO_SND_D_INPUT => "VIRTIO_SND_D_INPUT",
+        _ => unreachable!(),
+    }
+}
diff --git a/devices/src/virtio/snd/cras_backend/async_funcs.rs b/devices/src/virtio/snd/cras_backend/async_funcs.rs
index a5fd6b7573..d67a230728 100644
--- a/devices/src/virtio/snd/cras_backend/async_funcs.rs
+++ b/devices/src/virtio/snd/cras_backend/async_funcs.rs
@@ -6,7 +6,7 @@ use futures::{channel::mpsc, SinkExt, StreamExt};
 use std::io::{self, Write};
 use std::rc::Rc;
 
-use base::error;
+use base::{debug, error};
 use cros_async::{sync::Condvar, sync::Mutex as AsyncMutex, EventAsync, Executor};
 use data_model::{DataInit, Le32};
 use vm_memory::GuestMemory;
@@ -48,6 +48,12 @@ async fn process_pcm_ctrl(
         }
     };
 
+    debug!(
+        "{} for stream id={}",
+        get_virtio_snd_r_pcm_cmd_name(cmd_code),
+        stream_id
+    );
+
     let result = match cmd_code {
         VIRTIO_SND_R_PCM_PREPARE => {
             stream
@@ -548,6 +554,11 @@ pub async fn handle_ctrl_queue(
                     stream_info.direction = dir;
                     stream_info.state = VIRTIO_SND_R_PCM_SET_PARAMS;
 
+                    debug!(
+                        "VIRTIO_SND_R_PCM_SET_PARAMS for stream id={}. Stream info: {:#?}",
+                        stream_id, *stream_info
+                    );
+
                     writer
                         .write_obj(VIRTIO_SND_S_OK)
                         .map_err(Error::WriteResponse)
diff --git a/devices/src/virtio/snd/cras_backend/mod.rs b/devices/src/virtio/snd/cras_backend/mod.rs
index 5d2cf4c237..d870ce7358 100644
--- a/devices/src/virtio/snd/cras_backend/mod.rs
+++ b/devices/src/virtio/snd/cras_backend/mod.rs
@@ -4,6 +4,7 @@
 
 // virtio-sound spec: https://github.com/oasis-tcs/virtio-spec/blob/master/virtio-sound.tex
 
+use std::fmt;
 use std::io;
 use std::rc::Rc;
 use std::str::{FromStr, ParseBoolError};
@@ -160,6 +161,7 @@ pub enum WorkerStatus {
     Running = 1,
     Quit = 2,
 }
+
 pub struct StreamInfo<'a> {
     client: Option<CrasClient<'a>>,
     channels: u8,
@@ -167,8 +169,8 @@ pub struct StreamInfo<'a> {
     frame_rate: u32,
     buffer_bytes: usize,
     period_bytes: usize,
-    direction: u8,
-    state: u32, // VIRTIO_SND_R_PCM_SET_PARAMS -> VIRTIO_SND_R_PCM_STOP, or 0 (uninitialized)
+    direction: u8, // VIRTIO_SND_D_*
+    state: u32,    // VIRTIO_SND_R_PCM_SET_PARAMS -> VIRTIO_SND_R_PCM_STOP, or 0 (uninitialized)
 
     // Worker related
     status_mutex: Rc<AsyncMutex<WorkerStatus>>,
@@ -177,6 +179,20 @@ pub struct StreamInfo<'a> {
     worker_future: Option<Box<dyn Future<Output = Result<(), Error>> + Unpin>>,
 }
 
+impl fmt::Debug for StreamInfo<'_> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_struct("StreamInfo")
+            .field("channels", &self.channels)
+            .field("format", &self.format)
+            .field("frame_rate", &self.frame_rate)
+            .field("buffer_bytes", &self.buffer_bytes)
+            .field("period_bytes", &self.period_bytes)
+            .field("direction", &get_virtio_direction_name(self.direction))
+            .field("state", &get_virtio_snd_r_pcm_cmd_name(self.state))
+            .finish()
+    }
+}
+
 impl Default for StreamInfo<'_> {
     fn default() -> Self {
         StreamInfo {