Automatically reload sound system when alsa channel is skewed

Bug report: https://github.com/nicklan/pnmixer/issues/182

src/audio/alsa/backend.rs

@@ -352,5 +352,12 @@ fn on_alsa_event(
                 self::AudioUser::Unknown,
             );
         }
+        AlsaEvent::AlsaCardReload => {
+            invoke_handlers(
+                handlers,
+                self::AudioSignal::CardReload,
+                self::AudioUser::Unknown,
+            );
+        }
     }
 }

src/audio/alsa/card.rs

@@ -32,6 +32,8 @@ pub enum AlsaEvent {
     AlsaCardDiconnected,
     /// The values of the mixer changed, including mute state.
     AlsaCardValuesChanged,
+    /// Alsa needs to be reloaded due to recoverable error.
+    AlsaCardReload,
 }
 
 
@@ -236,8 +238,9 @@ extern "C" fn watch_cb(
                 continue;
             }
             glib_sys::G_IO_STATUS_NORMAL => {
-                error!("Alsa failed to clear the channel");
-                cb(AlsaEvent::AlsaCardError);
+                // BUG: https://github.com/nicklan/pnmixer/issues/182
+                warn!("Alsa failed to clear the channel");
+                cb(AlsaEvent::AlsaCardReload);
             }
             glib_sys::G_IO_STATUS_ERROR => (),
             glib_sys::G_IO_STATUS_EOF => {

src/audio/frontend.rs

@@ -49,6 +49,7 @@ pub enum AudioSignal {
     CardDisconnected,
     CardError,
     ValuesChanged,
+    CardReload,
 }
 
 

src/ui/entry.rs

@@ -72,7 +72,7 @@ where
                         &apps.prefs.borrow(),
                         AudioUser::Unknown,
                     ));
-                }
+                },
                 (AudioSignal::CardError, _) => {
                     if run_audio_error_dialog(
                         &apps.gui.popup_menu.menu_window,
@@ -84,7 +84,14 @@ where
                             AudioUser::Unknown,
                         ));
                     }
-                }
+                },
+                (AudioSignal::CardReload, _) => {
+                    try_w!(audio_reload(
+                        apps.audio.as_ref(),
+                        &apps.prefs.borrow(),
+                        AudioUser::Unknown,
+                    ));
+                },
                 _ => (),
             }),
         );