target/linux/brcm2708/patches-4.14/950-0254-Fix-for-Pisound-s-MIDI-Input-getting-blocked-for-a-w.patch

   1 From a845f23bddcb2b0e48e8158bb06b0990c4760e7e Mon Sep 17 00:00:00 2001
   2 From: Giedrius <giedrius@blokas.io>
   3 Date: Fri, 16 Mar 2018 18:14:31 +0200
   4 Subject: [PATCH 254/454] Fix for Pisound's MIDI Input getting blocked for a
   5  while in rare cases.
   6
   7 There was a possible race condition which could lead to Input's FIFO queue
   8 to be underflown, causing high amount of processing in the worker thread for
   9 some period of time.
  10
  11 Signed-off-by: Giedrius Trainavicius <giedrius@blokas.io>
  12 ---
  13  sound/soc/bcm/pisound.c | 12 +++++++-----
  14  1 file changed, 7 insertions(+), 5 deletions(-)
  15
  16 --- a/sound/soc/bcm/pisound.c
  17 +++ b/sound/soc/bcm/pisound.c
  18 @@ -56,6 +56,12 @@ static const char *pisnd_spi_get_version
  19  static int pisnd_midi_init(struct snd_card *card);
  20  static void pisnd_midi_uninit(void);
  21
  22 +enum task_e {
  23 +       TASK_PROCESS = 0,
  24 +};
  25 +
  26 +static void pisnd_schedule_process(enum task_e task);
  27 +
  28  #define PISOUND_LOG_PREFIX "pisound: "
  29
  30  #ifdef PISOUND_DEBUG
  31 @@ -129,7 +135,7 @@ static void pisnd_input_trigger(struct s
  32  {
  33         if (up) {
  34                 pisnd_spi_set_callback(pisnd_midi_recv_callback, substream);
  35 -               pisnd_midi_recv_callback(substream);
  36 +               pisnd_schedule_process(TASK_PROCESS);
  37         } else {
  38                 pisnd_spi_set_callback(NULL, NULL);
  39         }
  40 @@ -258,10 +264,6 @@ static bool pisnd_spi_has_more(void)
  41         return gpiod_get_value(data_available);
  42  }
  43
  44 -enum task_e {
  45 -       TASK_PROCESS = 0,
  46 -};
  47 -
  48  static void pisnd_schedule_process(enum task_e task)
  49  {
  50         if (pisnd_spi_device != NULL &&