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| author | Takashi Sakamoto <o-takashi@sakamocchi.jp> | 2021-05-20 06:01:51 +0200 |
|---|---|---|
| committer | Takashi Iwai <tiwai@suse.de> | 2021-05-20 14:00:38 +0200 |
| commit | 26541cb15a1a237b12b861b42231cc0a304545ed (patch) | |
| tree | e499f33139f388f9c16f892fff7db206fe1ed7e5 /sound/firewire/bebob | |
| parent | ALSA: firewire-lib: start processing content of packet at the same cycle in s... (diff) | |
| download | linux-26541cb15a1a237b12b861b42231cc0a304545ed.tar.xz linux-26541cb15a1a237b12b861b42231cc0a304545ed.zip | |
ALSA: firewire-lib: skip initial packets instead of scheduling IR context
Current implementation of ALSA IEC 61883-1/6 packet streaming engine
allows drivers to decide isochronous cycle to start IR context. This
option is mainly used to avoid processing the sequence of packet with
some quirks; e.g. discontinuity of counter. However, it's inconvenient
to fail to continue packet processing when the target device doesn't
start transmission of packet till the decided cycle.
This commit changes the behaviour. As an alternative to the start cycle
for IR context, the cycle count to drop content of packet in the beginning
of IR context.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20210520040154.80450-6-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound/firewire/bebob')
| -rw-r--r-- | sound/firewire/bebob/bebob_stream.c | 21 |
1 files changed, 8 insertions, 13 deletions
diff --git a/sound/firewire/bebob/bebob_stream.c b/sound/firewire/bebob/bebob_stream.c index b612ee3e33b6..8053d02b68f0 100644 --- a/sound/firewire/bebob/bebob_stream.c +++ b/sound/firewire/bebob/bebob_stream.c @@ -626,7 +626,7 @@ int snd_bebob_stream_start_duplex(struct snd_bebob *bebob) enum snd_bebob_clock_type src; struct amdtp_stream *master, *slave; unsigned int curr_rate; - unsigned int ir_delay_cycle; + unsigned int tx_init_skip_cycles; if (bebob->maudio_special_quirk) { err = bebob->spec->rate->get(bebob, &curr_rate); @@ -654,20 +654,13 @@ int snd_bebob_stream_start_duplex(struct snd_bebob *bebob) if (err < 0) goto error; - // The device postpones start of transmission mostly for 1 sec - // after receives packets firstly. For safe, IR context starts - // 0.4 sec (=3200 cycles) later to version 1 or 2 firmware, - // 2.0 sec (=16000 cycles) for version 3 firmware. This is - // within 2.5 sec (=CALLBACK_TIMEOUT). - // Furthermore, some devices transfer isoc packets with - // discontinuous counter in the beginning of packet streaming. - // The delay has an effect to avoid detection of this - // discontinuity. + // Some devices transfer isoc packets with discontinuous counter in the beginning + // of packet streaming. if (bebob->version < 2) - ir_delay_cycle = 3200; + tx_init_skip_cycles = 3200; else - ir_delay_cycle = 16000; - err = amdtp_domain_start(&bebob->domain, ir_delay_cycle); + tx_init_skip_cycles = 16000; + err = amdtp_domain_start(&bebob->domain, tx_init_skip_cycles); if (err < 0) goto error; @@ -684,6 +677,8 @@ int snd_bebob_stream_start_duplex(struct snd_bebob *bebob) } } + // Some devices postpone start of transmission mostly for 1 sec after receives + // packets firstly. if (!amdtp_stream_wait_callback(&bebob->rx_stream, CALLBACK_TIMEOUT) || !amdtp_stream_wait_callback(&bebob->tx_stream, |