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authorClemens Ladisch <clemens@ladisch.de>2012-05-13 22:03:09 +0200
committerTakashi Iwai <tiwai@suse.de>2012-05-14 10:43:30 +0200
commit76fb87894828756e069a43ce55f775a6c893a53d (patch)
tree270c4ca71a84ace95f7aef751477427365f395e3 /sound/firewire
parent7df4a691fb6645405c9d3dad8d27f8e5e3451e00 (diff)
downloadlinaro-lsk-76fb87894828756e069a43ce55f775a6c893a53d.tar.gz
ALSA: firewire-lib: taskletize the snd_pcm_period_elapsed() call
The following patch might introduce this call chain: PCM .pointer callback + fw_iso_context_flush_completions + packet callback + snd_pcm_period_elapsed + PCM .pointer callback Recursive calls to the pointer callback are not possible due to the PCM group locking, so avoid this by moving the period notification into a separate tasklet. Signed-off-by: Clemens Ladisch <clemens@ladisch.de> Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound/firewire')
-rw-r--r--sound/firewire/amdtp.c29
-rw-r--r--sound/firewire/amdtp.h15
2 files changed, 31 insertions, 13 deletions
diff --git a/sound/firewire/amdtp.c b/sound/firewire/amdtp.c
index 87657dd7714..3284ee9c1ec 100644
--- a/sound/firewire/amdtp.c
+++ b/sound/firewire/amdtp.c
@@ -31,6 +31,8 @@
#define INTERRUPT_INTERVAL 16
#define QUEUE_LENGTH 48
+static void pcm_period_tasklet(unsigned long data);
+
/**
* amdtp_out_stream_init - initialize an AMDTP output stream structure
* @s: the AMDTP output stream to initialize
@@ -47,6 +49,7 @@ int amdtp_out_stream_init(struct amdtp_out_stream *s, struct fw_unit *unit,
s->flags = flags;
s->context = ERR_PTR(-1);
mutex_init(&s->mutex);
+ tasklet_init(&s->period_tasklet, pcm_period_tasklet, (unsigned long)s);
s->packet_index = 0;
return 0;
@@ -164,6 +167,20 @@ void amdtp_out_stream_set_pcm_format(struct amdtp_out_stream *s,
}
EXPORT_SYMBOL(amdtp_out_stream_set_pcm_format);
+/**
+ * amdtp_out_stream_pcm_prepare - prepare PCM device for running
+ * @s: the AMDTP output stream
+ *
+ * This function should be called from the PCM device's .prepare callback.
+ */
+void amdtp_out_stream_pcm_prepare(struct amdtp_out_stream *s)
+{
+ tasklet_kill(&s->period_tasklet);
+ s->pcm_buffer_pointer = 0;
+ s->pcm_period_pointer = 0;
+}
+EXPORT_SYMBOL(amdtp_out_stream_pcm_prepare);
+
static unsigned int calculate_data_blocks(struct amdtp_out_stream *s)
{
unsigned int phase, data_blocks;
@@ -376,11 +393,20 @@ static void queue_out_packet(struct amdtp_out_stream *s, unsigned int cycle)
s->pcm_period_pointer += data_blocks;
if (s->pcm_period_pointer >= pcm->runtime->period_size) {
s->pcm_period_pointer -= pcm->runtime->period_size;
- snd_pcm_period_elapsed(pcm);
+ tasklet_hi_schedule(&s->period_tasklet);
}
}
}
+static void pcm_period_tasklet(unsigned long data)
+{
+ struct amdtp_out_stream *s = (void *)data;
+ struct snd_pcm_substream *pcm = ACCESS_ONCE(s->pcm);
+
+ if (pcm)
+ snd_pcm_period_elapsed(pcm);
+}
+
static void out_packet_callback(struct fw_iso_context *context, u32 cycle,
size_t header_length, void *header, void *data)
{
@@ -532,6 +558,7 @@ void amdtp_out_stream_stop(struct amdtp_out_stream *s)
return;
}
+ tasklet_kill(&s->period_tasklet);
fw_iso_context_stop(s->context);
fw_iso_context_destroy(s->context);
s->context = ERR_PTR(-1);
diff --git a/sound/firewire/amdtp.h b/sound/firewire/amdtp.h
index 537a9cb8358..4987f826f9f 100644
--- a/sound/firewire/amdtp.h
+++ b/sound/firewire/amdtp.h
@@ -1,6 +1,7 @@
#ifndef SOUND_FIREWIRE_AMDTP_H_INCLUDED
#define SOUND_FIREWIRE_AMDTP_H_INCLUDED
+#include <linux/interrupt.h>
#include <linux/mutex.h>
#include <linux/spinlock.h>
#include "packets-buffer.h"
@@ -55,6 +56,7 @@ struct amdtp_out_stream {
struct iso_packets_buffer buffer;
struct snd_pcm_substream *pcm;
+ struct tasklet_struct period_tasklet;
int packet_index;
unsigned int data_block_counter;
@@ -81,6 +83,7 @@ void amdtp_out_stream_stop(struct amdtp_out_stream *s);
void amdtp_out_stream_set_pcm_format(struct amdtp_out_stream *s,
snd_pcm_format_t format);
+void amdtp_out_stream_pcm_prepare(struct amdtp_out_stream *s);
void amdtp_out_stream_pcm_abort(struct amdtp_out_stream *s);
/**
@@ -123,18 +126,6 @@ static inline bool amdtp_out_streaming_error(struct amdtp_out_stream *s)
}
/**
- * amdtp_out_stream_pcm_prepare - prepare PCM device for running
- * @s: the AMDTP output stream
- *
- * This function should be called from the PCM device's .prepare callback.
- */
-static inline void amdtp_out_stream_pcm_prepare(struct amdtp_out_stream *s)
-{
- s->pcm_buffer_pointer = 0;
- s->pcm_period_pointer = 0;
-}
-
-/**
* amdtp_out_stream_pcm_trigger - start/stop playback from a PCM device
* @s: the AMDTP output stream
* @pcm: the PCM device to be started, or %NULL to stop the current device