mirror of
https://github.com/alsa-project/alsa-lib.git
synced 2025-11-02 09:01:48 -05:00
pcm: Remove home brew atomic operations
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@suse.de>
This commit is contained in:
Takashi Iwai
parent
54931e5a54
commit
7a8a1d1552
7 changed files with 20 additions and 305 deletions
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@ -3,7 +3,7 @@ DIST_SUBDIRS = scopes
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EXTRA_LTLIBRARIES = libpcm.la
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libpcm_la_SOURCES = atomic.c mask.c interval.c \
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libpcm_la_SOURCES = mask.c interval.c \
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pcm.c pcm_params.c pcm_simple.c \
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pcm_hw.c pcm_misc.c pcm_mmap.c pcm_symbols.c
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@ -1,43 +0,0 @@
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/*
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* Atomic read/write
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* Copyright (c) 2001 by Abramo Bagnara <abramo@alsa-project.org>
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*
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* This library is free software; you can redistribute it and/or modify
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* it under the terms of the GNU Lesser General Public License as
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* published by the Free Software Foundation; either version 2.1 of
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* the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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*/
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#include <stdlib.h>
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#include <time.h>
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#include <sched.h>
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#include "iatomic.h"
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void snd_atomic_read_wait(snd_atomic_read_t *t)
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{
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volatile const snd_atomic_write_t *w = t->write;
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unsigned int loops = 0;
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struct timespec ts;
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while (w->begin != w->end) {
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if (loops < MAX_SPIN_COUNT) {
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sched_yield();
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loops++;
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continue;
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}
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loops = 0;
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ts.tv_sec = 0;
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ts.tv_nsec = SPIN_SLEEP_DURATION;
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nanosleep(&ts, NULL);
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}
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}
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@ -133,7 +133,6 @@ void snd_pcm_plugin_init(snd_pcm_plugin_t *plugin)
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memset(plugin, 0, sizeof(snd_pcm_plugin_t));
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plugin->undo_read = snd_pcm_plugin_undo_read;
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plugin->undo_write = snd_pcm_plugin_undo_write;
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snd_atomic_write_init(&plugin->watom);
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}
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static int snd_pcm_plugin_delay(snd_pcm_t *pcm, snd_pcm_sframes_t *delayp)
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@ -157,15 +156,11 @@ static int snd_pcm_plugin_prepare(snd_pcm_t *pcm)
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{
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snd_pcm_plugin_t *plugin = pcm->private_data;
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int err;
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snd_atomic_write_begin(&plugin->watom);
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err = snd_pcm_prepare(plugin->gen.slave);
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if (err < 0) {
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snd_atomic_write_end(&plugin->watom);
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if (err < 0)
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return err;
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}
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*pcm->hw.ptr = 0;
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*pcm->appl.ptr = 0;
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snd_atomic_write_end(&plugin->watom);
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if (plugin->init) {
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err = plugin->init(pcm);
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if (err < 0)
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@ -178,15 +173,11 @@ static int snd_pcm_plugin_reset(snd_pcm_t *pcm)
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{
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snd_pcm_plugin_t *plugin = pcm->private_data;
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int err;
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snd_atomic_write_begin(&plugin->watom);
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err = snd_pcm_reset(plugin->gen.slave);
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if (err < 0) {
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snd_atomic_write_end(&plugin->watom);
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if (err < 0)
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return err;
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}
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*pcm->hw.ptr = 0;
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*pcm->appl.ptr = 0;
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snd_atomic_write_end(&plugin->watom);
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if (plugin->init) {
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err = plugin->init(pcm);
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if (err < 0)
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@ -212,14 +203,10 @@ snd_pcm_sframes_t snd_pcm_plugin_rewind(snd_pcm_t *pcm, snd_pcm_uframes_t frames
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return 0;
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sframes = frames;
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snd_atomic_write_begin(&plugin->watom);
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sframes = snd_pcm_rewind(plugin->gen.slave, sframes);
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if (sframes < 0) {
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snd_atomic_write_end(&plugin->watom);
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if (sframes < 0)
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return sframes;
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}
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snd_pcm_mmap_appl_backward(pcm, (snd_pcm_uframes_t) sframes);
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snd_atomic_write_end(&plugin->watom);
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return (snd_pcm_sframes_t) sframes;
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}
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@ -240,14 +227,10 @@ snd_pcm_sframes_t snd_pcm_plugin_forward(snd_pcm_t *pcm, snd_pcm_uframes_t frame
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return 0;
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sframes = frames;
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snd_atomic_write_begin(&plugin->watom);
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sframes = INTERNAL(snd_pcm_forward)(plugin->gen.slave, sframes);
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if (sframes < 0) {
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snd_atomic_write_end(&plugin->watom);
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if (sframes < 0)
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return sframes;
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}
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snd_pcm_mmap_appl_forward(pcm, (snd_pcm_uframes_t) frames);
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snd_atomic_write_end(&plugin->watom);
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return (snd_pcm_sframes_t) frames;
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}
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@ -279,31 +262,27 @@ static snd_pcm_sframes_t snd_pcm_plugin_write_areas(snd_pcm_t *pcm,
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err = -EPIPE;
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goto error;
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}
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snd_atomic_write_begin(&plugin->watom);
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result = snd_pcm_mmap_commit(slave, slave_offset, slave_frames);
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if (result > 0 && (snd_pcm_uframes_t)result != slave_frames) {
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snd_pcm_sframes_t res;
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res = plugin->undo_write(pcm, slave_areas, slave_offset + result, slave_frames, slave_frames - result);
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if (res < 0) {
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err = res;
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goto error_atomic;
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goto error;
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}
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frames -= res;
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}
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if (result <= 0) {
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err = result;
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goto error_atomic;
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goto error;
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}
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snd_pcm_mmap_appl_forward(pcm, frames);
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snd_atomic_write_end(&plugin->watom);
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offset += frames;
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xfer += frames;
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size -= frames;
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}
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return (snd_pcm_sframes_t)xfer;
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error_atomic:
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snd_atomic_write_end(&plugin->watom);
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error:
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return xfer > 0 ? (snd_pcm_sframes_t)xfer : err;
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}
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@ -336,7 +315,6 @@ static snd_pcm_sframes_t snd_pcm_plugin_read_areas(snd_pcm_t *pcm,
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err = -EPIPE;
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goto error;
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}
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snd_atomic_write_begin(&plugin->watom);
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result = snd_pcm_mmap_commit(slave, slave_offset, slave_frames);
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if (result > 0 && (snd_pcm_uframes_t)result != slave_frames) {
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snd_pcm_sframes_t res;
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@ -344,24 +322,21 @@ static snd_pcm_sframes_t snd_pcm_plugin_read_areas(snd_pcm_t *pcm,
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res = plugin->undo_read(slave, areas, offset, frames, slave_frames - result);
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if (res < 0) {
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err = res;
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goto error_atomic;
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goto error;
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}
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frames -= res;
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}
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if (result <= 0) {
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err = result;
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goto error_atomic;
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goto error;
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}
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snd_pcm_mmap_appl_forward(pcm, frames);
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snd_atomic_write_end(&plugin->watom);
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offset += frames;
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xfer += frames;
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size -= frames;
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}
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return (snd_pcm_sframes_t)xfer;
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error_atomic:
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snd_atomic_write_end(&plugin->watom);
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error:
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return xfer > 0 ? (snd_pcm_sframes_t)xfer : err;
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}
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@ -417,9 +392,7 @@ snd_pcm_plugin_mmap_commit(snd_pcm_t *pcm,
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int err;
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if (pcm->stream == SND_PCM_STREAM_CAPTURE) {
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snd_atomic_write_begin(&plugin->watom);
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snd_pcm_mmap_appl_forward(pcm, size);
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snd_atomic_write_end(&plugin->watom);
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return size;
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}
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slave_size = snd_pcm_avail_update(slave);
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@ -443,7 +416,6 @@ snd_pcm_plugin_mmap_commit(snd_pcm_t *pcm,
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frames = cont;
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frames = plugin->write(pcm, areas, appl_offset, frames,
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slave_areas, slave_offset, &slave_frames);
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snd_atomic_write_begin(&plugin->watom);
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result = snd_pcm_mmap_commit(slave, slave_offset, slave_frames);
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if (result > 0 && (snd_pcm_uframes_t)result != slave_frames) {
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snd_pcm_sframes_t res;
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@ -451,16 +423,15 @@ snd_pcm_plugin_mmap_commit(snd_pcm_t *pcm,
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res = plugin->undo_write(pcm, slave_areas, slave_offset + result, slave_frames, slave_frames - result);
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if (res < 0) {
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err = res;
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goto error_atomic;
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goto error;
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}
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frames -= res;
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}
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if (result <= 0) {
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err = result;
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goto error_atomic;
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goto error;
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}
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snd_pcm_mmap_appl_forward(pcm, frames);
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snd_atomic_write_end(&plugin->watom);
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if (frames == cont)
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appl_offset = 0;
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else
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@ -475,8 +446,6 @@ snd_pcm_plugin_mmap_commit(snd_pcm_t *pcm,
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}
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return xfer;
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error_atomic:
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snd_atomic_write_end(&plugin->watom);
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error:
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return xfer > 0 ? xfer : err;
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}
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@ -519,7 +488,6 @@ static snd_pcm_sframes_t snd_pcm_plugin_avail_update(snd_pcm_t *pcm)
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frames = cont;
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frames = (plugin->read)(pcm, areas, hw_offset, frames,
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slave_areas, slave_offset, &slave_frames);
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snd_atomic_write_begin(&plugin->watom);
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result = snd_pcm_mmap_commit(slave, slave_offset, slave_frames);
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if (result > 0 && (snd_pcm_uframes_t)result != slave_frames) {
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snd_pcm_sframes_t res;
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@ -527,16 +495,15 @@ static snd_pcm_sframes_t snd_pcm_plugin_avail_update(snd_pcm_t *pcm)
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res = plugin->undo_read(slave, areas, hw_offset, frames, slave_frames - result);
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if (res < 0) {
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err = res;
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goto error_atomic;
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goto error;
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}
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frames -= res;
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}
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if (result <= 0) {
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err = result;
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goto error_atomic;
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goto error;
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}
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snd_pcm_mmap_hw_forward(pcm, frames);
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snd_atomic_write_end(&plugin->watom);
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if (frames == cont)
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hw_offset = 0;
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else
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@ -547,8 +514,6 @@ static snd_pcm_sframes_t snd_pcm_plugin_avail_update(snd_pcm_t *pcm)
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}
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return (snd_pcm_sframes_t)xfer;
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error_atomic:
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snd_atomic_write_end(&plugin->watom);
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error:
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return xfer > 0 ? (snd_pcm_sframes_t)xfer : err;
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}
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@ -558,24 +523,15 @@ static int snd_pcm_plugin_status(snd_pcm_t *pcm, snd_pcm_status_t * status)
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{
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snd_pcm_plugin_t *plugin = pcm->private_data;
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snd_pcm_sframes_t err;
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snd_atomic_read_t ratom;
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snd_atomic_read_init(&ratom, &plugin->watom);
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_again:
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snd_atomic_read_begin(&ratom);
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/* sync with the latest hw and appl ptrs */
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snd_pcm_plugin_avail_update(pcm);
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err = snd_pcm_status(plugin->gen.slave, status);
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if (err < 0) {
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snd_atomic_read_ok(&ratom);
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if (err < 0)
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return err;
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}
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status->appl_ptr = *pcm->appl.ptr;
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status->hw_ptr = *pcm->hw.ptr;
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if (!snd_atomic_read_ok(&ratom)) {
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snd_atomic_read_wait(&ratom);
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goto _again;
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}
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return 0;
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}
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@ -19,7 +19,6 @@
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*
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*/
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#include "iatomic.h"
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#include "pcm_generic.h"
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typedef snd_pcm_uframes_t (*snd_pcm_slave_xfer_areas_func_t)
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@ -46,7 +45,6 @@ typedef struct {
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snd_pcm_slave_xfer_areas_undo_func_t undo_write;
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int (*init)(snd_pcm_t *pcm);
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snd_pcm_uframes_t appl_ptr, hw_ptr;
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snd_atomic_write_t watom;
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} snd_pcm_plugin_t;
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/* make local functions really local */
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@ -32,7 +32,6 @@
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#include "pcm_local.h"
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#include "pcm_plugin.h"
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#include "pcm_rate.h"
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#include "iatomic.h"
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#include "plugin_ops.h"
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@ -51,7 +50,6 @@ typedef struct _snd_pcm_rate snd_pcm_rate_t;
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struct _snd_pcm_rate {
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snd_pcm_generic_t gen;
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snd_atomic_write_t watom;
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snd_pcm_uframes_t appl_ptr, hw_ptr;
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snd_pcm_uframes_t last_commit_ptr;
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snd_pcm_uframes_t orig_avail_min;
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@ -584,9 +582,7 @@ static int snd_pcm_rate_hwsync(snd_pcm_t *pcm)
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int err = snd_pcm_hwsync(rate->gen.slave);
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if (err < 0)
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return err;
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snd_atomic_write_begin(&rate->watom);
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snd_pcm_rate_sync_hwptr(pcm);
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snd_atomic_write_end(&rate->watom);
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return 0;
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}
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@ -602,15 +598,11 @@ static int snd_pcm_rate_prepare(snd_pcm_t *pcm)
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snd_pcm_rate_t *rate = pcm->private_data;
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int err;
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snd_atomic_write_begin(&rate->watom);
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err = snd_pcm_prepare(rate->gen.slave);
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if (err < 0) {
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snd_atomic_write_end(&rate->watom);
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if (err < 0)
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return err;
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}
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*pcm->hw.ptr = 0;
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*pcm->appl.ptr = 0;
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snd_atomic_write_end(&rate->watom);
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err = snd_pcm_rate_init(pcm);
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if (err < 0)
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return err;
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@ -621,15 +613,11 @@ static int snd_pcm_rate_reset(snd_pcm_t *pcm)
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{
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snd_pcm_rate_t *rate = pcm->private_data;
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int err;
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snd_atomic_write_begin(&rate->watom);
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err = snd_pcm_reset(rate->gen.slave);
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if (err < 0) {
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snd_atomic_write_end(&rate->watom);
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if (err < 0)
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return err;
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}
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*pcm->hw.ptr = 0;
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*pcm->appl.ptr = 0;
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snd_atomic_write_end(&rate->watom);
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err = snd_pcm_rate_init(pcm);
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if (err < 0)
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return err;
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@ -923,9 +911,7 @@ static snd_pcm_sframes_t snd_pcm_rate_mmap_commit(snd_pcm_t *pcm,
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if (err < 0)
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return err;
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}
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snd_atomic_write_begin(&rate->watom);
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snd_pcm_mmap_appl_forward(pcm, size);
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snd_atomic_write_end(&rate->watom);
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return size;
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}
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@ -938,9 +924,7 @@ static snd_pcm_sframes_t snd_pcm_rate_avail_update(snd_pcm_t *pcm)
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slave_size = snd_pcm_avail_update(slave);
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if (pcm->stream == SND_PCM_STREAM_CAPTURE)
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goto _capture;
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snd_atomic_write_begin(&rate->watom);
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snd_pcm_rate_sync_hwptr(pcm);
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snd_atomic_write_end(&rate->watom);
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snd_pcm_rate_sync_playback_area(pcm, rate->appl_ptr);
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return snd_pcm_mmap_avail(pcm);
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_capture: {
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@ -1090,15 +1074,10 @@ static int snd_pcm_rate_status(snd_pcm_t *pcm, snd_pcm_status_t * status)
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{
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snd_pcm_rate_t *rate = pcm->private_data;
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snd_pcm_sframes_t err;
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snd_atomic_read_t ratom;
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snd_atomic_read_init(&ratom, &rate->watom);
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_again:
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snd_atomic_read_begin(&ratom);
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err = snd_pcm_status(rate->gen.slave, status);
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if (err < 0) {
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snd_atomic_read_ok(&ratom);
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if (err < 0)
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return err;
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}
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if (pcm->stream == SND_PCM_STREAM_PLAYBACK) {
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if (rate->start_pending)
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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) {
|
||||
|
|
|
|||
Loading…
Add table
Add a link
Reference in a new issue