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ALSA: firewire: use nonatomic PCM operation

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In the former commits, the callback of isochronous context runs on usual
work process. In the case, ALSA PCM device has a flag, nonatomic, to
acquire mutex lock instead of spin lock for PCM substream group.

This commit uses the flag. It has an advantage in the case that ALSA PCM
application uses the large size of intermediate buffer, since it takes
too long time even in tasklet softIRQ to process many of isochronous
packets, then result in the delay of system event due to disabled IRQ so
long. It is avertible to switch to nonatomic operation.

Reviewed-by: Takashi Iwai <tiwai@suse.de>
Tested-by: Edmund Raile <edmund.raile@protonmail.com>
Link: https://lore.kernel.org/r/20240904125155.461886-6-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
This commit is contained in:
Takashi Sakamoto 2024-09-04 21:51:54 +09:00
parent f62ec13e8b
commit 5c49cc0ed4
10 changed files with 36 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

34
sound/firewire/amdtp-stream.c
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@ -615,6 +615,22 @@ static void update_pcm_pointers(struct amdtp_stream *s,
// The program in user process should periodically check the status of intermediate
// buffer associated to PCM substream to process PCM frames in the buffer, instead
// of receiving notification of period elapsed by poll wait.
//
// Use another work item for period elapsed event to prevent the following AB/BA
// deadlock:
//
// thread 1 thread 2
// ================================= =================================
// A.work item (process) pcm ioctl (process)
// v v
// process_rx_packets() B.PCM stream lock
// process_tx_packets() v
// v callbacks in snd_pcm_ops
// update_pcm_pointers() v
// snd_pcm_elapsed() fw_iso_context_flush_completions()
// snd_pcm_stream_lock_irqsave() disable_work_sync()
// v v
// wait until release of B wait until A exits
if (!pcm->runtime->no_period_wakeup)
queue_work(system_highpri_wq, &s->period_work);
}
@ -1055,8 +1071,15 @@ static void generate_rx_packet_descs(struct amdtp_stream *s, struct pkt_desc *de
static inline void cancel_stream(struct amdtp_stream *s)
{
struct work_struct *work = current_work();
s->packet_index = -1;
if (in_softirq())
// Detect work items for any isochronous context. The work item for pcm_period_work()
// should be avoided since the call of snd_pcm_period_elapsed() can reach via
// snd_pcm_ops.pointer() under acquiring PCM stream(group) lock and causes dead lock at
// snd_pcm_stop_xrun().
if (work && work != &s->period_work)
amdtp_stream_pcm_abort(s);
WRITE_ONCE(s->pcm_buffer_pointer, SNDRV_PCM_POS_XRUN);
}
@ -1856,12 +1879,9 @@ unsigned long amdtp_domain_stream_pcm_pointer(struct amdtp_domain *d,
struct amdtp_stream *irq_target = d->irq_target;
if (irq_target && amdtp_stream_running(irq_target)) {
// use wq to prevent AB/BA deadlock competition for
// substream lock:
// fw_iso_context_flush_completions() acquires
// lock by ohci_flush_iso_completions(),
// amdtp-stream process_rx_packets() attempts to
// acquire same lock by snd_pcm_elapsed()
// The work item to call snd_pcm_period_elapsed() can reach here by the call of
// snd_pcm_ops.pointer(), however less packets would be available then. Therefore
// the following call is just for user process contexts.
if (current_work() != &s->period_work)
fw_iso_context_flush_completions(irq_target->context);
}

1
sound/firewire/bebob/bebob_pcm.c
View File

@ -367,6 +367,7 @@ int snd_bebob_create_pcm_devices(struct snd_bebob *bebob)
goto end;
pcm->private_data = bebob;
pcm->nonatomic = true;
snprintf(pcm->name, sizeof(pcm->name),
"%s PCM", bebob->card->shortname);
snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &playback_ops);

1
sound/firewire/dice/dice-pcm.c
View File

@ -441,6 +441,7 @@ int snd_dice_create_pcm(struct snd_dice *dice)
if (err < 0)
return err;
pcm->private_data = dice;
pcm->nonatomic = true;
strcpy(pcm->name, dice->card->shortname);
if (capture > 0)

1
sound/firewire/digi00x/digi00x-pcm.c
View File

@ -350,6 +350,7 @@ int snd_dg00x_create_pcm_devices(struct snd_dg00x *dg00x)
return err;
pcm->private_data = dg00x;
pcm->nonatomic = true;
snprintf(pcm->name, sizeof(pcm->name),
"%s PCM", dg00x->card->shortname);
snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &playback_ops);

1
sound/firewire/fireface/ff-pcm.c
View File

@ -390,6 +390,7 @@ int snd_ff_create_pcm_devices(struct snd_ff *ff)
return err;
pcm->private_data = ff;
pcm->nonatomic = true;
snprintf(pcm->name, sizeof(pcm->name),
"%s PCM", ff->card->shortname);
snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &pcm_playback_ops);

1
sound/firewire/fireworks/fireworks_pcm.c
View File

@ -397,6 +397,7 @@ int snd_efw_create_pcm_devices(struct snd_efw *efw)
goto end;
pcm->private_data = efw;
pcm->nonatomic = true;
snprintf(pcm->name, sizeof(pcm->name), "%s PCM", efw->card->shortname);
snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &playback_ops);
snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &capture_ops);

1
sound/firewire/isight.c
View File

@ -454,6 +454,7 @@ static int isight_create_pcm(struct isight *isight)
if (err < 0)
return err;
pcm->private_data = isight;
pcm->nonatomic = true;
strcpy(pcm->name, "iSight");
isight->pcm = pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream;
isight->pcm->ops = &ops;

1
sound/firewire/motu/motu-pcm.c
View File

@ -360,6 +360,7 @@ int snd_motu_create_pcm_devices(struct snd_motu *motu)
if (err < 0)
return err;
pcm->private_data = motu;
pcm->nonatomic = true;
strcpy(pcm->name, motu->card->shortname);
snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &capture_ops);

1
sound/firewire/oxfw/oxfw-pcm.c
View File

@ -440,6 +440,7 @@ int snd_oxfw_create_pcm(struct snd_oxfw *oxfw)
return err;
pcm->private_data = oxfw;
pcm->nonatomic = true;
strcpy(pcm->name, oxfw->card->shortname);
snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &playback_ops);
if (cap > 0)

1
sound/firewire/tascam/tascam-pcm.c
View File

@ -279,6 +279,7 @@ int snd_tscm_create_pcm_devices(struct snd_tscm *tscm)
return err;
pcm->private_data = tscm;
pcm->nonatomic = true;
snprintf(pcm->name, sizeof(pcm->name),
"%s PCM", tscm->card->shortname);
snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &playback_ops);