ALSA: bebob: delayed registration of sound card

Some bebob based units tends to fail asynchronous communication when
IEEE 1394 bus is under bus-reset state. When registering sound card
instance at unit probe callback, userspace applications can be involved
to the state.

This commit postpones the registration till the bus is calm.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/sound/firewire/bebob/bebob.c b/sound/firewire/bebob/bebob.c
index 932901d..f7e2cbd 100644 (file)
--- a/sound/firewire/bebob/bebob.c
+++ b/sound/firewire/bebob/bebob.c
@@ -126,6 +126,17 @@ end:
        return err;
 }
 
+static void bebob_free(struct snd_bebob *bebob)
+{
+       snd_bebob_stream_destroy_duplex(bebob);
+       fw_unit_put(bebob->unit);
+
+       kfree(bebob->maudio_special_quirk);
+
+       mutex_destroy(&bebob->mutex);
+       kfree(bebob);
+}
+
 /*
  * This module releases the FireWire unit data after all ALSA character devices
  * are released by applications. This is for releasing stream data or finishing
@@ -137,18 +148,11 @@ bebob_card_free(struct snd_card *card)
 {
        struct snd_bebob *bebob = card->private_data;
 
-       snd_bebob_stream_destroy_duplex(bebob);
-       fw_unit_put(bebob->unit);
-
-       kfree(bebob->maudio_special_quirk);
-
-       if (bebob->card_index >= 0) {
-               mutex_lock(&devices_mutex);
-               clear_bit(bebob->card_index, devices_used);
-               mutex_unlock(&devices_mutex);
-       }
+       mutex_lock(&devices_mutex);
+       clear_bit(bebob->card_index, devices_used);
+       mutex_unlock(&devices_mutex);
 
-       mutex_destroy(&bebob->mutex);
+       bebob_free(card->private_data);
 }
 
 static const struct snd_bebob_spec *
@@ -176,16 +180,17 @@ check_audiophile_booted(struct fw_unit *unit)
        return strncmp(name, "FW Audiophile Bootloader", 15) != 0;
 }
 
-static int
-bebob_probe(struct fw_unit *unit,
-           const struct ieee1394_device_id *entry)
+static void
+do_registration(struct work_struct *work)
 {
-       struct snd_card *card;
-       struct snd_bebob *bebob;
-       const struct snd_bebob_spec *spec;
+       struct snd_bebob *bebob =
+                       container_of(work, struct snd_bebob, dwork.work);
        unsigned int card_index;
        int err;
 
+       if (bebob->registered)
+               return;
+
        mutex_lock(&devices_mutex);
 
        for (card_index = 0; card_index < SNDRV_CARDS; card_index++) {
@@ -193,64 +198,39 @@ bebob_probe(struct fw_unit *unit,
                        break;
        }
        if (card_index >= SNDRV_CARDS) {
-               err = -ENOENT;
-               goto end;
+               mutex_unlock(&devices_mutex);
+               return;
        }
 
-       if ((entry->vendor_id == VEN_FOCUSRITE) &&
-           (entry->model_id == MODEL_FOCUSRITE_SAFFIRE_BOTH))
-               spec = get_saffire_spec(unit);
-       else if ((entry->vendor_id == VEN_MAUDIO1) &&
-                (entry->model_id == MODEL_MAUDIO_AUDIOPHILE_BOTH) &&
-                !check_audiophile_booted(unit))
-               spec = NULL;
-       else
-               spec = (const struct snd_bebob_spec *)entry->driver_data;
-
-       if (spec == NULL) {
-               if ((entry->vendor_id == VEN_MAUDIO1) ||
-                   (entry->vendor_id == VEN_MAUDIO2))
-                       err = snd_bebob_maudio_load_firmware(unit);
-               else
-                       err = -ENOSYS;
-               goto end;
+       err = snd_card_new(&bebob->unit->device, index[card_index],
+                          id[card_index], THIS_MODULE, 0, &bebob->card);
+       if (err < 0) {
+               mutex_unlock(&devices_mutex);
+               return;
        }
 
-       err = snd_card_new(&unit->device, index[card_index], id[card_index],
-                          THIS_MODULE, sizeof(struct snd_bebob), &card);
-       if (err < 0)
-               goto end;
-       bebob = card->private_data;
-       bebob->card_index = card_index;
-       set_bit(card_index, devices_used);
-       card->private_free = bebob_card_free;
-
-       bebob->card = card;
-       bebob->unit = fw_unit_get(unit);
-       bebob->spec = spec;
-       mutex_init(&bebob->mutex);
-       spin_lock_init(&bebob->lock);
-       init_waitqueue_head(&bebob->hwdep_wait);
-
        err = name_device(bebob);
        if (err < 0)
                goto error;
 
-       if ((entry->vendor_id == VEN_MAUDIO1) &&
-           (entry->model_id == MODEL_MAUDIO_FW1814))
-               err = snd_bebob_maudio_special_discover(bebob, true);
-       else if ((entry->vendor_id == VEN_MAUDIO1) &&
-                (entry->model_id == MODEL_MAUDIO_PROJECTMIX))
-               err = snd_bebob_maudio_special_discover(bebob, false);
-       else
+       if (bebob->spec == &maudio_special_spec) {
+               if (bebob->entry->model_id == MODEL_MAUDIO_FW1814)
+                       err = snd_bebob_maudio_special_discover(bebob, true);
+               else
+                       err = snd_bebob_maudio_special_discover(bebob, false);
+       } else {
                err = snd_bebob_stream_discover(bebob);
+       }
+       if (err < 0)
+               goto error;
+
+       err = snd_bebob_stream_init_duplex(bebob);
        if (err < 0)
                goto error;
 
        snd_bebob_proc_init(bebob);
 
-       if ((bebob->midi_input_ports > 0) ||
-           (bebob->midi_output_ports > 0)) {
+       if (bebob->midi_input_ports > 0 || bebob->midi_output_ports > 0) {
                err = snd_bebob_create_midi_devices(bebob);
                if (err < 0)
                        goto error;
@@ -264,16 +244,75 @@ bebob_probe(struct fw_unit *unit,
        if (err < 0)
                goto error;
 
-       err = snd_bebob_stream_init_duplex(bebob);
+       err = snd_card_register(bebob->card);
        if (err < 0)
                goto error;
 
-       if (!bebob->maudio_special_quirk) {
-               err = snd_card_register(card);
-               if (err < 0) {
-                       snd_bebob_stream_destroy_duplex(bebob);
-                       goto error;
-               }
+       set_bit(card_index, devices_used);
+       mutex_unlock(&devices_mutex);
+
+       /*
+        * After registered, bebob instance can be released corresponding to
+        * releasing the sound card instance.
+        */
+       bebob->card->private_free = bebob_card_free;
+       bebob->card->private_data = bebob;
+       bebob->registered = true;
+
+       return;
+error:
+       mutex_unlock(&devices_mutex);
+       snd_bebob_stream_destroy_duplex(bebob);
+       snd_card_free(bebob->card);
+       dev_info(&bebob->unit->device,
+                "Sound card registration failed: %d\n", err);
+}
+
+static int
+bebob_probe(struct fw_unit *unit, const struct ieee1394_device_id *entry)
+{
+       struct snd_bebob *bebob;
+       const struct snd_bebob_spec *spec;
+
+       if (entry->vendor_id == VEN_FOCUSRITE &&
+           entry->model_id == MODEL_FOCUSRITE_SAFFIRE_BOTH)
+               spec = get_saffire_spec(unit);
+       else if (entry->vendor_id == VEN_MAUDIO1 &&
+                entry->model_id == MODEL_MAUDIO_AUDIOPHILE_BOTH &&
+                !check_audiophile_booted(unit))
+               spec = NULL;
+       else
+               spec = (const struct snd_bebob_spec *)entry->driver_data;
+
+       if (spec == NULL) {
+               if (entry->vendor_id == VEN_MAUDIO1 ||
+                   entry->vendor_id == VEN_MAUDIO2)
+                       return snd_bebob_maudio_load_firmware(unit);
+               else
+                       return -ENODEV;
+       }
+
+       /* Allocate this independent of sound card instance. */
+       bebob = kzalloc(sizeof(struct snd_bebob), GFP_KERNEL);
+       if (bebob == NULL)
+               return -ENOMEM;
+
+       bebob->unit = fw_unit_get(unit);
+       bebob->entry = entry;
+       bebob->spec = spec;
+       dev_set_drvdata(&unit->device, bebob);
+
+       mutex_init(&bebob->mutex);
+       spin_lock_init(&bebob->lock);
+       init_waitqueue_head(&bebob->hwdep_wait);
+
+       /* Allocate and register this sound card later. */
+       INIT_DEFERRABLE_WORK(&bebob->dwork, do_registration);
+
+       if (entry->vendor_id != VEN_MAUDIO1 ||
+           (entry->model_id != MODEL_MAUDIO_FW1814 &&
+            entry->model_id != MODEL_MAUDIO_PROJECTMIX)) {
+               snd_fw_schedule_registration(unit, &bebob->dwork);
        } else {
                /*
                 * This is a workaround. This bus reset seems to have an effect
@@ -285,19 +324,11 @@ bebob_probe(struct fw_unit *unit,
                 * signals from dbus and starts I/Os. To avoid I/Os till the
                 * future bus reset, registration is done in next update().
                 */
-               bebob->deferred_registration = true;
                fw_schedule_bus_reset(fw_parent_device(bebob->unit)->card,
                                      false, true);
        }
 
-       dev_set_drvdata(&unit->device, bebob);
-end:
-       mutex_unlock(&devices_mutex);
-       return err;
-error:
-       mutex_unlock(&devices_mutex);
-       snd_card_free(card);
-       return err;
+       return 0;
 }
 
 /*
@@ -324,15 +355,11 @@ bebob_update(struct fw_unit *unit)
        if (bebob == NULL)
                return;
 
-       fcp_bus_reset(bebob->unit);
-
-       if (bebob->deferred_registration) {
-               if (snd_card_register(bebob->card) < 0) {
-                       snd_bebob_stream_destroy_duplex(bebob);
-                       snd_card_free(bebob->card);
-               }
-               bebob->deferred_registration = false;
-       }
+       /* Postpone a workqueue for deferred registration. */
+       if (!bebob->registered)
+               snd_fw_schedule_registration(unit, &bebob->dwork);
+       else
+               fcp_bus_reset(bebob->unit);
 }
 
 static void bebob_remove(struct fw_unit *unit)
@@ -342,8 +369,20 @@ static void bebob_remove(struct fw_unit *unit)
        if (bebob == NULL)
                return;
 
-       /* No need to wait for releasing card object in this context. */
-       snd_card_free_when_closed(bebob->card);
+       /*
+        * Confirm to stop the work for registration before the sound card is
+        * going to be released. The work is not scheduled again because bus
+        * reset handler is not called anymore.
+        */
+       cancel_delayed_work_sync(&bebob->dwork);
+
+       if (bebob->registered) {
+               /* No need to wait for releasing card object in this context. */
+               snd_card_free_when_closed(bebob->card);
+       } else {
+               /* Don't forget this case. */
+               bebob_free(bebob);
+       }
 }
 
 static const struct snd_bebob_rate_spec normal_rate_spec = {

diff --git a/sound/firewire/bebob/bebob.h b/sound/firewire/bebob/bebob.h
index b50bb33..2a442a7 100644 (file)
--- a/sound/firewire/bebob/bebob.h
+++ b/sound/firewire/bebob/bebob.h
@@ -83,6 +83,10 @@ struct snd_bebob {
        struct mutex mutex;
        spinlock_t lock;
 
+       bool registered;
+       struct delayed_work dwork;
+
+       const struct ieee1394_device_id *entry;
        const struct snd_bebob_spec *spec;
 
        unsigned int midi_input_ports;
@@ -111,7 +115,6 @@ struct snd_bebob {
 
        /* for M-Audio special devices */
        void *maudio_special_quirk;
-       bool deferred_registration;
 
        /* For BeBoB version quirk. */
        unsigned int version;