[alsa-devel] [PATCH 6/8] ALSA: oxfw: delayed registration of sound card
Takashi Sakamoto
o-takashi at sakamocchi.jp
Thu Mar 31 01:47:07 CEST 2016
Some oxfw 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 at sakamocchi.jp>
---
sound/firewire/oxfw/oxfw.c | 151 +++++++++++++++++++++++++++++----------------
sound/firewire/oxfw/oxfw.h | 3 +
2 files changed, 101 insertions(+), 53 deletions(-)
diff --git a/sound/firewire/oxfw/oxfw.c b/sound/firewire/oxfw/oxfw.c
index abedc22..e629b88 100644
--- a/sound/firewire/oxfw/oxfw.c
+++ b/sound/firewire/oxfw/oxfw.c
@@ -118,15 +118,8 @@ end:
return err;
}
-/*
- * This module releases the FireWire unit data after all ALSA character devices
- * are released by applications. This is for releasing stream data or finishing
- * transactions safely. Thus at returning from .remove(), this module still keep
- * references for the unit.
- */
-static void oxfw_card_free(struct snd_card *card)
+static void oxfw_free(struct snd_oxfw *oxfw)
{
- struct snd_oxfw *oxfw = card->private_data;
unsigned int i;
snd_oxfw_stream_destroy_simplex(oxfw, &oxfw->rx_stream);
@@ -144,6 +137,17 @@ static void oxfw_card_free(struct snd_card *card)
mutex_destroy(&oxfw->mutex);
}
+/*
+ * This module releases the FireWire unit data after all ALSA character devices
+ * are released by applications. This is for releasing stream data or finishing
+ * transactions safely. Thus at returning from .remove(), this module still keep
+ * references for the unit.
+ */
+static void oxfw_card_free(struct snd_card *card)
+{
+ oxfw_free(card->private_data);
+}
+
static int detect_quirks(struct snd_oxfw *oxfw)
{
struct fw_device *fw_dev = fw_parent_device(oxfw->unit);
@@ -205,41 +209,39 @@ static int detect_quirks(struct snd_oxfw *oxfw)
return 0;
}
-static int oxfw_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_oxfw *oxfw;
+ struct snd_oxfw *oxfw = container_of(work, struct snd_oxfw, dwork.work);
int err;
- if (entry->vendor_id == VENDOR_LOUD && !detect_loud_models(unit))
- return -ENODEV;
+ if (oxfw->registered)
+ return;
- err = snd_card_new(&unit->device, -1, NULL, THIS_MODULE,
- sizeof(*oxfw), &card);
+ err = snd_card_new(&oxfw->unit->device, -1, NULL, THIS_MODULE, 0,
+ &oxfw->card);
if (err < 0)
- return err;
+ return;
- card->private_free = oxfw_card_free;
- oxfw = card->private_data;
- oxfw->card = card;
- mutex_init(&oxfw->mutex);
- oxfw->unit = fw_unit_get(unit);
- oxfw->entry = entry;
- spin_lock_init(&oxfw->lock);
- init_waitqueue_head(&oxfw->hwdep_wait);
+ err = name_card(oxfw);
+ if (err < 0)
+ goto error;
- err = snd_oxfw_stream_discover(oxfw);
+ err = detect_quirks(oxfw);
if (err < 0)
goto error;
- err = name_card(oxfw);
+ err = snd_oxfw_stream_discover(oxfw);
if (err < 0)
goto error;
- err = detect_quirks(oxfw);
+ err = snd_oxfw_stream_init_simplex(oxfw, &oxfw->rx_stream);
if (err < 0)
goto error;
+ if (oxfw->has_output) {
+ err = snd_oxfw_stream_init_simplex(oxfw, &oxfw->tx_stream);
+ if (err < 0)
+ goto error;
+ }
err = snd_oxfw_create_pcm(oxfw);
if (err < 0)
@@ -255,54 +257,97 @@ static int oxfw_probe(struct fw_unit *unit,
if (err < 0)
goto error;
- err = snd_oxfw_stream_init_simplex(oxfw, &oxfw->rx_stream);
+ err = snd_card_register(oxfw->card);
if (err < 0)
goto error;
- if (oxfw->has_output) {
- err = snd_oxfw_stream_init_simplex(oxfw, &oxfw->tx_stream);
- if (err < 0)
- goto error;
- }
- err = snd_card_register(card);
- if (err < 0) {
- snd_oxfw_stream_destroy_simplex(oxfw, &oxfw->rx_stream);
- if (oxfw->has_output)
- snd_oxfw_stream_destroy_simplex(oxfw, &oxfw->tx_stream);
- goto error;
- }
+ /*
+ * After registered, oxfw instance can be released corresponding to
+ * releasing the sound card instance.
+ */
+ oxfw->card->private_free = oxfw_card_free;
+ oxfw->card->private_data = oxfw;
+ oxfw->registered = true;
+
+ return;
+error:
+ snd_oxfw_stream_destroy_simplex(oxfw, &oxfw->rx_stream);
+ if (oxfw->has_output)
+ snd_oxfw_stream_destroy_simplex(oxfw, &oxfw->tx_stream);
+ snd_card_free(oxfw->card);
+ dev_info(&oxfw->unit->device,
+ "Sound card registration failed: %d\n", err);
+}
+
+static int oxfw_probe(struct fw_unit *unit,
+ const struct ieee1394_device_id *entry)
+{
+ struct snd_oxfw *oxfw;
+
+ if (entry->vendor_id == VENDOR_LOUD && !detect_loud_models(unit))
+ return -ENODEV;
+
+ /* Allocate this independent of sound card instance. */
+ oxfw = kzalloc(sizeof(struct snd_oxfw), GFP_KERNEL);
+ if (oxfw == NULL)
+ return -ENOMEM;
+
+ oxfw->entry = entry;
+ oxfw->unit = fw_unit_get(unit);
dev_set_drvdata(&unit->device, oxfw);
+ mutex_init(&oxfw->mutex);
+ spin_lock_init(&oxfw->lock);
+ init_waitqueue_head(&oxfw->hwdep_wait);
+
+ /* Allocate and register this sound card later. */
+ INIT_DEFERRABLE_WORK(&oxfw->dwork, do_registration);
+ snd_fw_schedule_registration(unit, &oxfw->dwork);
+
return 0;
-error:
- snd_card_free(card);
- return err;
}
static void oxfw_bus_reset(struct fw_unit *unit)
{
struct snd_oxfw *oxfw = dev_get_drvdata(&unit->device);
+ if (!oxfw->registered)
+ snd_fw_schedule_registration(unit, &oxfw->dwork);
+
fcp_bus_reset(oxfw->unit);
- mutex_lock(&oxfw->mutex);
+ if (oxfw->registered) {
+ mutex_lock(&oxfw->mutex);
- snd_oxfw_stream_update_simplex(oxfw, &oxfw->rx_stream);
- if (oxfw->has_output)
- snd_oxfw_stream_update_simplex(oxfw, &oxfw->tx_stream);
+ snd_oxfw_stream_update_simplex(oxfw, &oxfw->rx_stream);
+ if (oxfw->has_output)
+ snd_oxfw_stream_update_simplex(oxfw, &oxfw->tx_stream);
- mutex_unlock(&oxfw->mutex);
+ mutex_unlock(&oxfw->mutex);
- if (oxfw->entry->vendor_id == OUI_STANTON)
- snd_oxfw_scs1x_update(oxfw);
+ if (oxfw->entry->vendor_id == OUI_STANTON)
+ snd_oxfw_scs1x_update(oxfw);
+ }
}
static void oxfw_remove(struct fw_unit *unit)
{
struct snd_oxfw *oxfw = dev_get_drvdata(&unit->device);
- /* No need to wait for releasing card object in this context. */
- snd_card_free_when_closed(oxfw->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(&oxfw->dwork);
+
+ if (oxfw->registered) {
+ /* No need to wait for releasing card object in this context. */
+ snd_card_free_when_closed(oxfw->card);
+ } else {
+ /* Don't forget this case. */
+ oxfw_free(oxfw);
+ }
}
static const struct compat_info griffin_firewave = {
diff --git a/sound/firewire/oxfw/oxfw.h b/sound/firewire/oxfw/oxfw.h
index 2c84714e..2047dcb 100644
--- a/sound/firewire/oxfw/oxfw.h
+++ b/sound/firewire/oxfw/oxfw.h
@@ -39,6 +39,9 @@ struct snd_oxfw {
struct mutex mutex;
spinlock_t lock;
+ bool registered;
+ struct delayed_work dwork;
+
bool wrong_dbs;
bool has_output;
u8 *tx_stream_formats[SND_OXFW_STREAM_FORMAT_ENTRIES];
--
2.7.4
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