[alsa-devel] [PATCH alsa-lib v2 2/3] pcm: Remove home brew atomic operations
Takashi Iwai
tiwai at suse.de
Thu Jul 7 16:40:12 CEST 2016
We've had a few home brew atomic operations in a couple of places in
the PCM code. This was for supporting the concurrent accesses, but in
practice, it couldn't cover the race properly by itself alone.
Since we have a wider concurrency protection via mutex now, we can get
rid of these atomic codes, which worsens the portability
significantly.
Signed-off-by: Takashi Iwai <tiwai at suse.de>
---
include/Makefile.am | 2 +-
include/iatomic.h | 170 ---------------------------------------------------
src/pcm/Makefile.am | 2 +-
src/pcm/atomic.c | 43 -------------
src/pcm/pcm_plugin.c | 72 +++++-----------------
src/pcm/pcm_plugin.h | 2 -
src/pcm/pcm_rate.c | 34 ++---------
7 files changed, 20 insertions(+), 305 deletions(-)
delete mode 100644 include/iatomic.h
delete mode 100644 src/pcm/atomic.c
diff --git a/include/Makefile.am b/include/Makefile.am
index 31a3f748dc46..67f32e36c911 100644
--- a/include/Makefile.am
+++ b/include/Makefile.am
@@ -5,7 +5,7 @@ alsaincludedir = ${includedir}/alsa
alsainclude_HEADERS = asoundlib.h asoundef.h \
version.h global.h input.h output.h error.h \
- conf.h control.h iatomic.h
+ conf.h control.h
if BUILD_CTL_PLUGIN_EXT
alsainclude_HEADERS += control_external.h
diff --git a/include/iatomic.h b/include/iatomic.h
deleted file mode 100644
index acdd3e29c13a..000000000000
--- a/include/iatomic.h
+++ /dev/null
@@ -1,170 +0,0 @@
-#ifndef __ALSA_IATOMIC_H
-#define __ALSA_IATOMIC_H
-
-#ifdef __i386__
-#define mb() __asm__ __volatile__ ("lock; addl $0,0(%%esp)": : :"memory")
-#define rmb() mb()
-#define wmb() __asm__ __volatile__ ("": : :"memory")
-#define IATOMIC_DEFINED 1
-#endif
-
-#ifdef __x86_64__
-#define mb() asm volatile("mfence":::"memory")
-#define rmb() asm volatile("lfence":::"memory")
-#define wmb() asm volatile("sfence":::"memory")
-#define IATOMIC_DEFINED 1
-#endif
-
-#ifdef __ia64__
-/*
- * Macros to force memory ordering. In these descriptions, "previous"
- * and "subsequent" refer to program order; "visible" means that all
- * architecturally visible effects of a memory access have occurred
- * (at a minimum, this means the memory has been read or written).
- *
- * wmb(): Guarantees that all preceding stores to memory-
- * like regions are visible before any subsequent
- * stores and that all following stores will be
- * visible only after all previous stores.
- * rmb(): Like wmb(), but for reads.
- * mb(): wmb()/rmb() combo, i.e., all previous memory
- * accesses are visible before all subsequent
- * accesses and vice versa. This is also known as
- * a "fence."
- *
- * Note: "mb()" and its variants cannot be used as a fence to order
- * accesses to memory mapped I/O registers. For that, mf.a needs to
- * be used. However, we don't want to always use mf.a because (a)
- * it's (presumably) much slower than mf and (b) mf.a is supported for
- * sequential memory pages only.
- */
-#define mb() __asm__ __volatile__ ("mf" ::: "memory")
-#define rmb() mb()
-#define wmb() mb()
-
-#define IATOMIC_DEFINED 1
-
-#endif /* __ia64__ */
-
-#ifdef __alpha__
-
-#define mb() \
-__asm__ __volatile__("mb": : :"memory")
-
-#define rmb() \
-__asm__ __volatile__("mb": : :"memory")
-
-#define wmb() \
-__asm__ __volatile__("wmb": : :"memory")
-
-#define IATOMIC_DEFINED 1
-
-#endif /* __alpha__ */
-
-#ifdef __powerpc__
-
-/*
- * Memory barrier.
- * The sync instruction guarantees that all memory accesses initiated
- * by this processor have been performed (with respect to all other
- * mechanisms that access memory). The eieio instruction is a barrier
- * providing an ordering (separately) for (a) cacheable stores and (b)
- * loads and stores to non-cacheable memory (e.g. I/O devices).
- *
- * mb() prevents loads and stores being reordered across this point.
- * rmb() prevents loads being reordered across this point.
- * wmb() prevents stores being reordered across this point.
- *
- * We can use the eieio instruction for wmb, but since it doesn't
- * give any ordering guarantees about loads, we have to use the
- * stronger but slower sync instruction for mb and rmb.
- */
-#define mb() __asm__ __volatile__ ("sync" : : : "memory")
-#define rmb() __asm__ __volatile__ ("sync" : : : "memory")
-#define wmb() __asm__ __volatile__ ("eieio" : : : "memory")
-
-#define IATOMIC_DEFINED 1
-
-#endif /* __powerpc__ */
-
-#ifndef IATOMIC_DEFINED
-
-/* Generic __sync_synchronize is available from gcc 4.1 */
-
-#define mb() __sync_synchronize()
-#define rmb() mb()
-#define wmb() mb()
-
-#define IATOMIC_DEFINED 1
-
-#endif /* IATOMIC_DEFINED */
-
-/*
- * Atomic read/write
- * Copyright (c) 2001 by Abramo Bagnara <abramo at alsa-project.org>
- */
-
-/* Max number of times we must spin on a spin-lock calling sched_yield().
- After MAX_SPIN_COUNT iterations, we put the calling thread to sleep. */
-
-#ifndef MAX_SPIN_COUNT
-#define MAX_SPIN_COUNT 50
-#endif
-
-/* Duration of sleep (in nanoseconds) when we can't acquire a spin-lock
- after MAX_SPIN_COUNT iterations of sched_yield().
- This MUST BE > 2ms.
- (Otherwise the kernel does busy-waiting for real-time threads,
- giving other threads no chance to run.) */
-
-#ifndef SPIN_SLEEP_DURATION
-#define SPIN_SLEEP_DURATION 2000001
-#endif
-
-typedef struct {
- unsigned int begin, end;
-} snd_atomic_write_t;
-
-typedef struct {
- volatile const snd_atomic_write_t *write;
- unsigned int end;
-} snd_atomic_read_t;
-
-void snd_atomic_read_wait(snd_atomic_read_t *t);
-
-static __inline__ void snd_atomic_write_init(snd_atomic_write_t *w)
-{
- w->begin = 0;
- w->end = 0;
-}
-
-static __inline__ void snd_atomic_write_begin(snd_atomic_write_t *w)
-{
- w->begin++;
- wmb();
-}
-
-static __inline__ void snd_atomic_write_end(snd_atomic_write_t *w)
-{
- wmb();
- w->end++;
-}
-
-static __inline__ void snd_atomic_read_init(snd_atomic_read_t *r, snd_atomic_write_t *w)
-{
- r->write = w;
-}
-
-static __inline__ void snd_atomic_read_begin(snd_atomic_read_t *r)
-{
- r->end = r->write->end;
- rmb();
-}
-
-static __inline__ int snd_atomic_read_ok(snd_atomic_read_t *r)
-{
- rmb();
- return r->end == r->write->begin;
-}
-
-#endif /* __ALSA_IATOMIC_H */
diff --git a/src/pcm/Makefile.am b/src/pcm/Makefile.am
index 81598f634bc3..8edbd0b5c719 100644
--- a/src/pcm/Makefile.am
+++ b/src/pcm/Makefile.am
@@ -3,7 +3,7 @@ DIST_SUBDIRS = scopes
EXTRA_LTLIBRARIES = libpcm.la
-libpcm_la_SOURCES = atomic.c mask.c interval.c \
+libpcm_la_SOURCES = mask.c interval.c \
pcm.c pcm_params.c pcm_simple.c \
pcm_hw.c pcm_misc.c pcm_mmap.c pcm_symbols.c
diff --git a/src/pcm/atomic.c b/src/pcm/atomic.c
deleted file mode 100644
index 75659457af76..000000000000
--- a/src/pcm/atomic.c
+++ /dev/null
@@ -1,43 +0,0 @@
-/*
- * Atomic read/write
- * Copyright (c) 2001 by Abramo Bagnara <abramo at alsa-project.org>
- *
- * This library is free software; you can redistribute it and/or modify
- * it under the terms of the GNU Lesser General Public License as
- * published by the Free Software Foundation; either version 2.1 of
- * the License, or (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
- *
- */
-
-#include <stdlib.h>
-#include <time.h>
-#include <sched.h>
-#include "iatomic.h"
-
-void snd_atomic_read_wait(snd_atomic_read_t *t)
-{
- volatile const snd_atomic_write_t *w = t->write;
- unsigned int loops = 0;
- struct timespec ts;
- while (w->begin != w->end) {
- if (loops < MAX_SPIN_COUNT) {
- sched_yield();
- loops++;
- continue;
- }
- loops = 0;
- ts.tv_sec = 0;
- ts.tv_nsec = SPIN_SLEEP_DURATION;
- nanosleep(&ts, NULL);
- }
-}
-
diff --git a/src/pcm/pcm_plugin.c b/src/pcm/pcm_plugin.c
index 8527783c3569..e53c5bb5568e 100644
--- a/src/pcm/pcm_plugin.c
+++ b/src/pcm/pcm_plugin.c
@@ -133,7 +133,6 @@ void snd_pcm_plugin_init(snd_pcm_plugin_t *plugin)
memset(plugin, 0, sizeof(snd_pcm_plugin_t));
plugin->undo_read = snd_pcm_plugin_undo_read;
plugin->undo_write = snd_pcm_plugin_undo_write;
- snd_atomic_write_init(&plugin->watom);
}
static int snd_pcm_plugin_delay(snd_pcm_t *pcm, snd_pcm_sframes_t *delayp)
@@ -157,15 +156,11 @@ static int snd_pcm_plugin_prepare(snd_pcm_t *pcm)
{
snd_pcm_plugin_t *plugin = pcm->private_data;
int err;
- snd_atomic_write_begin(&plugin->watom);
err = snd_pcm_prepare(plugin->gen.slave);
- if (err < 0) {
- snd_atomic_write_end(&plugin->watom);
+ if (err < 0)
return err;
- }
*pcm->hw.ptr = 0;
*pcm->appl.ptr = 0;
- snd_atomic_write_end(&plugin->watom);
if (plugin->init) {
err = plugin->init(pcm);
if (err < 0)
@@ -178,15 +173,11 @@ static int snd_pcm_plugin_reset(snd_pcm_t *pcm)
{
snd_pcm_plugin_t *plugin = pcm->private_data;
int err;
- snd_atomic_write_begin(&plugin->watom);
err = snd_pcm_reset(plugin->gen.slave);
- if (err < 0) {
- snd_atomic_write_end(&plugin->watom);
+ if (err < 0)
return err;
- }
*pcm->hw.ptr = 0;
*pcm->appl.ptr = 0;
- snd_atomic_write_end(&plugin->watom);
if (plugin->init) {
err = plugin->init(pcm);
if (err < 0)
@@ -212,14 +203,10 @@ snd_pcm_sframes_t snd_pcm_plugin_rewind(snd_pcm_t *pcm, snd_pcm_uframes_t frames
return 0;
sframes = frames;
- snd_atomic_write_begin(&plugin->watom);
sframes = snd_pcm_rewind(plugin->gen.slave, sframes);
- if (sframes < 0) {
- snd_atomic_write_end(&plugin->watom);
+ if (sframes < 0)
return sframes;
- }
snd_pcm_mmap_appl_backward(pcm, (snd_pcm_uframes_t) sframes);
- snd_atomic_write_end(&plugin->watom);
return (snd_pcm_sframes_t) sframes;
}
@@ -240,14 +227,10 @@ snd_pcm_sframes_t snd_pcm_plugin_forward(snd_pcm_t *pcm, snd_pcm_uframes_t frame
return 0;
sframes = frames;
- snd_atomic_write_begin(&plugin->watom);
sframes = INTERNAL(snd_pcm_forward)(plugin->gen.slave, sframes);
- if (sframes < 0) {
- snd_atomic_write_end(&plugin->watom);
+ if (sframes < 0)
return sframes;
- }
snd_pcm_mmap_appl_forward(pcm, (snd_pcm_uframes_t) frames);
- snd_atomic_write_end(&plugin->watom);
return (snd_pcm_sframes_t) frames;
}
@@ -279,31 +262,27 @@ static snd_pcm_sframes_t snd_pcm_plugin_write_areas(snd_pcm_t *pcm,
err = -EPIPE;
goto error;
}
- snd_atomic_write_begin(&plugin->watom);
result = snd_pcm_mmap_commit(slave, slave_offset, slave_frames);
if (result > 0 && (snd_pcm_uframes_t)result != slave_frames) {
snd_pcm_sframes_t res;
res = plugin->undo_write(pcm, slave_areas, slave_offset + result, slave_frames, slave_frames - result);
if (res < 0) {
err = res;
- goto error_atomic;
+ goto error;
}
frames -= res;
}
if (result <= 0) {
err = result;
- goto error_atomic;
+ goto error;
}
snd_pcm_mmap_appl_forward(pcm, frames);
- snd_atomic_write_end(&plugin->watom);
offset += frames;
xfer += frames;
size -= frames;
}
return (snd_pcm_sframes_t)xfer;
- error_atomic:
- snd_atomic_write_end(&plugin->watom);
error:
return xfer > 0 ? (snd_pcm_sframes_t)xfer : err;
}
@@ -336,7 +315,6 @@ static snd_pcm_sframes_t snd_pcm_plugin_read_areas(snd_pcm_t *pcm,
err = -EPIPE;
goto error;
}
- snd_atomic_write_begin(&plugin->watom);
result = snd_pcm_mmap_commit(slave, slave_offset, slave_frames);
if (result > 0 && (snd_pcm_uframes_t)result != slave_frames) {
snd_pcm_sframes_t res;
@@ -344,24 +322,21 @@ static snd_pcm_sframes_t snd_pcm_plugin_read_areas(snd_pcm_t *pcm,
res = plugin->undo_read(slave, areas, offset, frames, slave_frames - result);
if (res < 0) {
err = res;
- goto error_atomic;
+ goto error;
}
frames -= res;
}
if (result <= 0) {
err = result;
- goto error_atomic;
+ goto error;
}
snd_pcm_mmap_appl_forward(pcm, frames);
- snd_atomic_write_end(&plugin->watom);
offset += frames;
xfer += frames;
size -= frames;
}
return (snd_pcm_sframes_t)xfer;
- error_atomic:
- snd_atomic_write_end(&plugin->watom);
error:
return xfer > 0 ? (snd_pcm_sframes_t)xfer : err;
}
@@ -417,9 +392,7 @@ snd_pcm_plugin_mmap_commit(snd_pcm_t *pcm,
int err;
if (pcm->stream == SND_PCM_STREAM_CAPTURE) {
- snd_atomic_write_begin(&plugin->watom);
snd_pcm_mmap_appl_forward(pcm, size);
- snd_atomic_write_end(&plugin->watom);
return size;
}
slave_size = snd_pcm_avail_update(slave);
@@ -443,7 +416,6 @@ snd_pcm_plugin_mmap_commit(snd_pcm_t *pcm,
frames = cont;
frames = plugin->write(pcm, areas, appl_offset, frames,
slave_areas, slave_offset, &slave_frames);
- snd_atomic_write_begin(&plugin->watom);
result = snd_pcm_mmap_commit(slave, slave_offset, slave_frames);
if (result > 0 && (snd_pcm_uframes_t)result != slave_frames) {
snd_pcm_sframes_t res;
@@ -451,16 +423,15 @@ snd_pcm_plugin_mmap_commit(snd_pcm_t *pcm,
res = plugin->undo_write(pcm, slave_areas, slave_offset + result, slave_frames, slave_frames - result);
if (res < 0) {
err = res;
- goto error_atomic;
+ goto error;
}
frames -= res;
}
if (result <= 0) {
err = result;
- goto error_atomic;
+ goto error;
}
snd_pcm_mmap_appl_forward(pcm, frames);
- snd_atomic_write_end(&plugin->watom);
if (frames == cont)
appl_offset = 0;
else
@@ -475,8 +446,6 @@ snd_pcm_plugin_mmap_commit(snd_pcm_t *pcm,
}
return xfer;
- error_atomic:
- snd_atomic_write_end(&plugin->watom);
error:
return xfer > 0 ? xfer : err;
}
@@ -519,7 +488,6 @@ static snd_pcm_sframes_t snd_pcm_plugin_avail_update(snd_pcm_t *pcm)
frames = cont;
frames = (plugin->read)(pcm, areas, hw_offset, frames,
slave_areas, slave_offset, &slave_frames);
- snd_atomic_write_begin(&plugin->watom);
result = snd_pcm_mmap_commit(slave, slave_offset, slave_frames);
if (result > 0 && (snd_pcm_uframes_t)result != slave_frames) {
snd_pcm_sframes_t res;
@@ -527,16 +495,15 @@ static snd_pcm_sframes_t snd_pcm_plugin_avail_update(snd_pcm_t *pcm)
res = plugin->undo_read(slave, areas, hw_offset, frames, slave_frames - result);
if (res < 0) {
err = res;
- goto error_atomic;
+ goto error;
}
frames -= res;
}
if (result <= 0) {
err = result;
- goto error_atomic;
+ goto error;
}
snd_pcm_mmap_hw_forward(pcm, frames);
- snd_atomic_write_end(&plugin->watom);
if (frames == cont)
hw_offset = 0;
else
@@ -547,8 +514,6 @@ static snd_pcm_sframes_t snd_pcm_plugin_avail_update(snd_pcm_t *pcm)
}
return (snd_pcm_sframes_t)xfer;
- error_atomic:
- snd_atomic_write_end(&plugin->watom);
error:
return xfer > 0 ? (snd_pcm_sframes_t)xfer : err;
}
@@ -558,24 +523,15 @@ static int snd_pcm_plugin_status(snd_pcm_t *pcm, snd_pcm_status_t * status)
{
snd_pcm_plugin_t *plugin = pcm->private_data;
snd_pcm_sframes_t err;
- snd_atomic_read_t ratom;
- snd_atomic_read_init(&ratom, &plugin->watom);
- _again:
- snd_atomic_read_begin(&ratom);
+
/* sync with the latest hw and appl ptrs */
snd_pcm_plugin_avail_update(pcm);
err = snd_pcm_status(plugin->gen.slave, status);
- if (err < 0) {
- snd_atomic_read_ok(&ratom);
+ if (err < 0)
return err;
- }
status->appl_ptr = *pcm->appl.ptr;
status->hw_ptr = *pcm->hw.ptr;
- if (!snd_atomic_read_ok(&ratom)) {
- snd_atomic_read_wait(&ratom);
- goto _again;
- }
return 0;
}
diff --git a/src/pcm/pcm_plugin.h b/src/pcm/pcm_plugin.h
index b0a3e1869ea1..217f0757ea59 100644
--- a/src/pcm/pcm_plugin.h
+++ b/src/pcm/pcm_plugin.h
@@ -19,7 +19,6 @@
*
*/
-#include "iatomic.h"
#include "pcm_generic.h"
typedef snd_pcm_uframes_t (*snd_pcm_slave_xfer_areas_func_t)
@@ -46,7 +45,6 @@ typedef struct {
snd_pcm_slave_xfer_areas_undo_func_t undo_write;
int (*init)(snd_pcm_t *pcm);
snd_pcm_uframes_t appl_ptr, hw_ptr;
- snd_atomic_write_t watom;
} snd_pcm_plugin_t;
/* make local functions really local */
diff --git a/src/pcm/pcm_rate.c b/src/pcm/pcm_rate.c
index 06854fdee7f9..6184defbdde3 100644
--- a/src/pcm/pcm_rate.c
+++ b/src/pcm/pcm_rate.c
@@ -32,7 +32,6 @@
#include "pcm_local.h"
#include "pcm_plugin.h"
#include "pcm_rate.h"
-#include "iatomic.h"
#include "plugin_ops.h"
@@ -51,7 +50,6 @@ typedef struct _snd_pcm_rate snd_pcm_rate_t;
struct _snd_pcm_rate {
snd_pcm_generic_t gen;
- snd_atomic_write_t watom;
snd_pcm_uframes_t appl_ptr, hw_ptr;
snd_pcm_uframes_t last_commit_ptr;
snd_pcm_uframes_t orig_avail_min;
@@ -584,9 +582,7 @@ static int snd_pcm_rate_hwsync(snd_pcm_t *pcm)
int err = snd_pcm_hwsync(rate->gen.slave);
if (err < 0)
return err;
- snd_atomic_write_begin(&rate->watom);
snd_pcm_rate_sync_hwptr(pcm);
- snd_atomic_write_end(&rate->watom);
return 0;
}
@@ -602,15 +598,11 @@ static int snd_pcm_rate_prepare(snd_pcm_t *pcm)
snd_pcm_rate_t *rate = pcm->private_data;
int err;
- snd_atomic_write_begin(&rate->watom);
err = snd_pcm_prepare(rate->gen.slave);
- if (err < 0) {
- snd_atomic_write_end(&rate->watom);
+ if (err < 0)
return err;
- }
*pcm->hw.ptr = 0;
*pcm->appl.ptr = 0;
- snd_atomic_write_end(&rate->watom);
err = snd_pcm_rate_init(pcm);
if (err < 0)
return err;
@@ -621,15 +613,11 @@ static int snd_pcm_rate_reset(snd_pcm_t *pcm)
{
snd_pcm_rate_t *rate = pcm->private_data;
int err;
- snd_atomic_write_begin(&rate->watom);
err = snd_pcm_reset(rate->gen.slave);
- if (err < 0) {
- snd_atomic_write_end(&rate->watom);
+ if (err < 0)
return err;
- }
*pcm->hw.ptr = 0;
*pcm->appl.ptr = 0;
- snd_atomic_write_end(&rate->watom);
err = snd_pcm_rate_init(pcm);
if (err < 0)
return err;
@@ -923,9 +911,7 @@ static snd_pcm_sframes_t snd_pcm_rate_mmap_commit(snd_pcm_t *pcm,
if (err < 0)
return err;
}
- snd_atomic_write_begin(&rate->watom);
snd_pcm_mmap_appl_forward(pcm, size);
- snd_atomic_write_end(&rate->watom);
return size;
}
@@ -938,9 +924,7 @@ static snd_pcm_sframes_t snd_pcm_rate_avail_update(snd_pcm_t *pcm)
slave_size = snd_pcm_avail_update(slave);
if (pcm->stream == SND_PCM_STREAM_CAPTURE)
goto _capture;
- snd_atomic_write_begin(&rate->watom);
snd_pcm_rate_sync_hwptr(pcm);
- snd_atomic_write_end(&rate->watom);
snd_pcm_rate_sync_playback_area(pcm, rate->appl_ptr);
return snd_pcm_mmap_avail(pcm);
_capture: {
@@ -1090,15 +1074,10 @@ static int snd_pcm_rate_status(snd_pcm_t *pcm, snd_pcm_status_t * status)
{
snd_pcm_rate_t *rate = pcm->private_data;
snd_pcm_sframes_t err;
- snd_atomic_read_t ratom;
- snd_atomic_read_init(&ratom, &rate->watom);
- _again:
- snd_atomic_read_begin(&ratom);
+
err = snd_pcm_status(rate->gen.slave, status);
- if (err < 0) {
- snd_atomic_read_ok(&ratom);
+ if (err < 0)
return err;
- }
if (pcm->stream == SND_PCM_STREAM_PLAYBACK) {
if (rate->start_pending)
status->state = SND_PCM_STATE_RUNNING;
@@ -1116,10 +1095,6 @@ static int snd_pcm_rate_status(snd_pcm_t *pcm, snd_pcm_status_t * status)
status->avail = snd_pcm_mmap_capture_avail(pcm);
status->avail_max = rate->ops.output_frames(rate->obj, status->avail_max);
}
- if (!snd_atomic_read_ok(&ratom)) {
- snd_atomic_read_wait(&ratom);
- goto _again;
- }
return 0;
}
@@ -1309,7 +1284,6 @@ int snd_pcm_rate_open(snd_pcm_t **pcmp, const char *name,
rate->gen.close_slave = close_slave;
rate->srate = srate;
rate->sformat = sformat;
- snd_atomic_write_init(&rate->watom);
err = snd_pcm_new(&pcm, SND_PCM_TYPE_RATE, name, slave->stream, slave->mode);
if (err < 0) {
--
2.9.0
More information about the Alsa-devel
mailing list