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ALSA: firewire/bebob: Add a workaround for M-Audio special Firewire series 

In post commit, a quirk of this firmware about transactions is reported.
This commit apply a workaround for this quirk.

They often fail transactions due to gap_count mismatch. This state is changed
by generating bus reset.

The fw_schedule_bus_reset() is an exported symbol in firewire-core. But there
are no header for public. This commit moves its prototype from
drivers/firewire/core.h to include/linux/firewire.h.

This mismatch still affects bus management before generating this bus reset.
It still takes a time to call driver's probe() because transactions are still
often failed.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Takashi Sakamoto 2014-04-25 22:45:30 +09:00 committed by Takashi Iwai
parent a2b2a7798f
commit 9b1ee0b2cb
4 changed files with 32 additions and 5 deletions
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1
drivers/firewire/core.h
View File

@ -118,7 +118,6 @@ int fw_card_add(struct fw_card *card,
u32 max_receive, u32 link_speed, u64 guid);
void fw_core_remove_card(struct fw_card *card);
int fw_compute_block_crc(__be32 *block);
void fw_schedule_bus_reset(struct fw_card *card, bool delayed, bool short_reset);
void fw_schedule_bm_work(struct fw_card *card, unsigned long delay);
/* -cdev */

3
include/linux/firewire.h
View File

@ -367,6 +367,9 @@ static inline int fw_stream_packet_destination_id(int tag, int channel, int sy)
return tag << 14 | channel << 8 | sy;
}
void fw_schedule_bus_reset(struct fw_card *card, bool delayed,
bool short_reset);
struct fw_descriptor {
struct list_head link;
size_t length;

32
sound/firewire/bebob/bebob.c
View File

@ -247,10 +247,26 @@ bebob_probe(struct fw_unit *unit,
if (err < 0)
goto error;
err = snd_card_register(card);
if (err < 0) {
snd_bebob_stream_destroy_duplex(bebob);
goto error;
if (!bebob->maudio_special_quirk) {
err = snd_card_register(card);
if (err < 0) {
snd_bebob_stream_destroy_duplex(bebob);
goto error;
}
} else {
/*
* This is a workaround. This bus reset seems to have an effect
* to make devices correctly handling transactions. Without
* this, the devices have gap_count mismatch. This causes much
* failure of transaction.
*
* Just after registration, user-land application receive
* 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);
@ -273,6 +289,14 @@ bebob_update(struct fw_unit *unit)
fcp_bus_reset(bebob->unit);
snd_bebob_stream_update_duplex(bebob);
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;
}
}
static void bebob_remove(struct fw_unit *unit)

1
sound/firewire/bebob/bebob.h
View File

@ -109,6 +109,7 @@ struct snd_bebob {
/* for M-Audio special devices */
void *maudio_special_quirk;
bool deferred_registration;
};
static inline int