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ALSA: firewire-lib: add new function to schedule a work for sound card registration

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In former commit, ALSA dice driver postpone sound card registration after
IEEE 1394 bus is calm. This idea has advantages for the other drivers.

This commit adds a helper function for it to firewire-lib module. The
function is really for the specific purpose. Callers should initialize
delayed work structure with callback function.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Takashi Sakamoto 2016-03-31 08:47:04 +09:00 committed by Takashi Iwai
parent 0eced45ca6
commit 923f92ebb4
3 changed files with 38 additions and 20 deletions
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23
sound/firewire/dice/dice.c
View File

@ -20,8 +20,6 @@ MODULE_LICENSE("GPL v2");
#define WEISS_CATEGORY_ID 0x00
#define LOUD_CATEGORY_ID 0x10
#define PROBE_DELAY_MS (2 * MSEC_PER_SEC)
/*
* Some models support several isochronous channels, while these streams are not
* always available. In this case, add the model name to this list.
@ -235,27 +233,12 @@ static void do_registration(struct work_struct *work)
error:
snd_dice_stream_destroy_duplex(dice);
snd_dice_transaction_destroy(dice);
snd_dice_stream_destroy_duplex(dice);
snd_card_free(dice->card);
dev_info(&dice->unit->device,
"Sound card registration failed: %d\n", err);
}
static void schedule_registration(struct snd_dice *dice)
{
struct fw_card *fw_card = fw_parent_device(dice->unit)->card;
u64 now, delay;
now = get_jiffies_64();
delay = fw_card->reset_jiffies + msecs_to_jiffies(PROBE_DELAY_MS);
if (time_after64(delay, now))
delay -= now;
else
delay = 0;
mod_delayed_work(system_wq, &dice->dwork, delay);
}
static int dice_probe(struct fw_unit *unit, const struct ieee1394_device_id *id)
{
struct snd_dice *dice;
@ -280,7 +263,7 @@ static int dice_probe(struct fw_unit *unit, const struct ieee1394_device_id *id)
/* Allocate and register this sound card later. */
INIT_DEFERRABLE_WORK(&dice->dwork, do_registration);
schedule_registration(dice);
snd_fw_schedule_registration(unit, &dice->dwork);
return 0;
}
@ -311,7 +294,7 @@ static void dice_bus_reset(struct fw_unit *unit)
/* Postpone a workqueue for deferred registration. */
if (!dice->registered)
schedule_registration(dice);
snd_fw_schedule_registration(unit, &dice->dwork);
/* The handler address register becomes initialized. */
snd_dice_transaction_reinit(dice);

32
sound/firewire/lib.c
View File

@ -67,6 +67,38 @@ int snd_fw_transaction(struct fw_unit *unit, int tcode,
}
EXPORT_SYMBOL(snd_fw_transaction);
#define PROBE_DELAY_MS (2 * MSEC_PER_SEC)
/**
* snd_fw_schedule_registration - schedule work for sound card registration
* @unit: an instance for unit on IEEE 1394 bus
* @dwork: delayed work with callback function
*
* This function is not designed for general purposes. When new unit is
* connected to IEEE 1394 bus, the bus is under bus-reset state because of
* topological change. In this state, units tend to fail both of asynchronous
* and isochronous communication. To avoid this problem, this function is used
* to postpone sound card registration after the state. The callers must
* set up instance of delayed work in advance.
*/
void snd_fw_schedule_registration(struct fw_unit *unit,
struct delayed_work *dwork)
{
u64 now, delay;
now = get_jiffies_64();
delay = fw_parent_device(unit)->card->reset_jiffies
+ msecs_to_jiffies(PROBE_DELAY_MS);
if (time_after64(delay, now))
delay -= now;
else
delay = 0;
mod_delayed_work(system_wq, dwork, delay);
}
EXPORT_SYMBOL(snd_fw_schedule_registration);
static void async_midi_port_callback(struct fw_card *card, int rcode,
void *data, size_t length,
void *callback_data)

3
sound/firewire/lib.h
View File

@ -22,6 +22,9 @@ static inline bool rcode_is_permanent_error(int rcode)
return rcode == RCODE_TYPE_ERROR || rcode == RCODE_ADDRESS_ERROR;
}
void snd_fw_schedule_registration(struct fw_unit *unit,
struct delayed_work *dwork);
struct snd_fw_async_midi_port;
typedef int (*snd_fw_async_midi_port_fill)(
struct snd_rawmidi_substream *substream,