From 9b1ee0b2cb8bffdbb3003b1d5205f3ae0592c15a Mon Sep 17 00:00:00 2001 From: Takashi Sakamoto Date: Fri, 25 Apr 2014 22:45:30 +0900 Subject: [PATCH 49/61] 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 Signed-off-by: Takashi Iwai --- drivers/firewire/core.h | 1 - include/linux/firewire.h | 3 +++ sound/firewire/bebob/bebob.c | 32 ++++++++++++++++++++++++++++---- sound/firewire/bebob/bebob.h | 1 + 4 files changed, 32 insertions(+), 5 deletions(-) diff --git a/drivers/firewire/core.h b/drivers/firewire/core.h index c98764aeeec6..870044e82316 100644 --- a/drivers/firewire/core.h +++ b/drivers/firewire/core.h @@ -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 */ diff --git a/include/linux/firewire.h b/include/linux/firewire.h index c3683bdf28fe..d4b7683c722d 100644 --- a/include/linux/firewire.h +++ b/include/linux/firewire.h @@ -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; diff --git a/sound/firewire/bebob/bebob.c b/sound/firewire/bebob/bebob.c index e1dd4219ea6c..31b96b7264cf 100644 --- a/sound/firewire/bebob/bebob.c +++ b/sound/firewire/bebob/bebob.c @@ -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) diff --git a/sound/firewire/bebob/bebob.h b/sound/firewire/bebob/bebob.h index 4a54e746c5c6..91b26b0c649a 100644 --- a/sound/firewire/bebob/bebob.h +++ b/sound/firewire/bebob/bebob.h @@ -109,6 +109,7 @@ struct snd_bebob { /* for M-Audio special devices */ void *maudio_special_quirk; + bool deferred_registration; }; static inline int -- 1.8.5.5