Fix for Pisound's MIDI Input getting blocked for a while in rare cases.

There was a possible race condition which could lead to Input's FIFO queue
to be underflown, causing high amount of processing in the worker thread for
some period of time.

Signed-off-by: Giedrius Trainavicius <giedrius@blokas.io>

diff --git a/sound/soc/bcm/pisound.c b/sound/soc/bcm/pisound.c
index 00ae628acdd296e785cd87081703adb8decafe6e..ab9ea1f32931aa65c55c2a3b74a96da2d4ac126e 100644 (file)
--- a/sound/soc/bcm/pisound.c
+++ b/sound/soc/bcm/pisound.c
@@ -56,6 +56,12 @@ static const char *pisnd_spi_get_version(void);
 static int pisnd_midi_init(struct snd_card *card);
 static void pisnd_midi_uninit(void);
 
+enum task_e {
+       TASK_PROCESS = 0,
+};
+
+static void pisnd_schedule_process(enum task_e task);
+
 #define PISOUND_LOG_PREFIX "pisound: "
 
 #ifdef PISOUND_DEBUG
@@ -129,7 +135,7 @@ static void pisnd_input_trigger(struct snd_rawmidi_substream *substream, int up)
 {
        if (up) {
                pisnd_spi_set_callback(pisnd_midi_recv_callback, substream);
-               pisnd_midi_recv_callback(substream);
+               pisnd_schedule_process(TASK_PROCESS);
        } else {
                pisnd_spi_set_callback(NULL, NULL);
        }
@@ -258,10 +264,6 @@ static bool pisnd_spi_has_more(void)
        return gpiod_get_value(data_available);
 }
 
-enum task_e {
-       TASK_PROCESS = 0,
-};
-
 static void pisnd_schedule_process(enum task_e task)
 {
        if (pisnd_spi_device != NULL &&