ALSA: pcm_lib - optimize wake_up() calls for PCM I/O
As noted by pl bossart <bossart.nospam@gmail.com>, the PCM I/O routines
(snd_pcm_lib_write1, snd_pcm_lib_read1) should block wake_up() calls
until all samples are not processed.
Signed-off-by: Jaroslav Kysela <perex@perex.cz>
diff --git a/sound/core/pcm_lib.c b/sound/core/pcm_lib.c
index 70a4f74..a632262 100644
--- a/sound/core/pcm_lib.c
+++ b/sound/core/pcm_lib.c
@@ -263,8 +263,8 @@
#endif
-static int snd_pcm_update_hw_ptr_post(struct snd_pcm_substream *substream,
- struct snd_pcm_runtime *runtime)
+int snd_pcm_update_state(struct snd_pcm_substream *substream,
+ struct snd_pcm_runtime *runtime)
{
snd_pcm_uframes_t avail;
@@ -285,7 +285,7 @@
return -EPIPE;
}
}
- if (avail >= runtime->control->avail_min)
+ if (!runtime->nowake && avail >= runtime->control->avail_min)
wake_up(&runtime->sleep);
return 0;
}
@@ -441,7 +441,7 @@
if (runtime->tstamp_mode == SNDRV_PCM_TSTAMP_ENABLE)
snd_pcm_gettime(runtime, (struct timespec *)&runtime->status->tstamp);
- return snd_pcm_update_hw_ptr_post(substream, runtime);
+ return snd_pcm_update_state(substream, runtime);
}
/* CAUTION: call it with irq disabled */
@@ -1792,6 +1792,7 @@
goto _end_unlock;
}
+ runtime->nowake = 1;
while (size > 0) {
snd_pcm_uframes_t frames, appl_ptr, appl_ofs;
snd_pcm_uframes_t avail;
@@ -1813,15 +1814,17 @@
if (frames > cont)
frames = cont;
if (snd_BUG_ON(!frames)) {
+ runtime->nowake = 0;
snd_pcm_stream_unlock_irq(substream);
return -EINVAL;
}
appl_ptr = runtime->control->appl_ptr;
appl_ofs = appl_ptr % runtime->buffer_size;
snd_pcm_stream_unlock_irq(substream);
- if ((err = transfer(substream, appl_ofs, data, offset, frames)) < 0)
- goto _end;
+ err = transfer(substream, appl_ofs, data, offset, frames);
snd_pcm_stream_lock_irq(substream);
+ if (err < 0)
+ goto _end_unlock;
switch (runtime->status->state) {
case SNDRV_PCM_STATE_XRUN:
err = -EPIPE;
@@ -1850,8 +1853,10 @@
}
}
_end_unlock:
+ runtime->nowake = 0;
+ if (xfer > 0 && err >= 0)
+ snd_pcm_update_state(substream, runtime);
snd_pcm_stream_unlock_irq(substream);
- _end:
return xfer > 0 ? (snd_pcm_sframes_t)xfer : err;
}
@@ -2009,6 +2014,7 @@
goto _end_unlock;
}
+ runtime->nowake = 1;
while (size > 0) {
snd_pcm_uframes_t frames, appl_ptr, appl_ofs;
snd_pcm_uframes_t avail;
@@ -2037,15 +2043,17 @@
if (frames > cont)
frames = cont;
if (snd_BUG_ON(!frames)) {
+ runtime->nowake = 0;
snd_pcm_stream_unlock_irq(substream);
return -EINVAL;
}
appl_ptr = runtime->control->appl_ptr;
appl_ofs = appl_ptr % runtime->buffer_size;
snd_pcm_stream_unlock_irq(substream);
- if ((err = transfer(substream, appl_ofs, data, offset, frames)) < 0)
- goto _end;
+ err = transfer(substream, appl_ofs, data, offset, frames);
snd_pcm_stream_lock_irq(substream);
+ if (err < 0)
+ goto _end_unlock;
switch (runtime->status->state) {
case SNDRV_PCM_STATE_XRUN:
err = -EPIPE;
@@ -2068,8 +2076,10 @@
xfer += frames;
}
_end_unlock:
+ runtime->nowake = 0;
+ if (xfer > 0 && err >= 0)
+ snd_pcm_update_state(substream, runtime);
snd_pcm_stream_unlock_irq(substream);
- _end:
return xfer > 0 ? (snd_pcm_sframes_t)xfer : err;
}
