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Add "nonblock" option for hw layer

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Added a new "nonblock" option for hw layer.  This controls the non-blocking
"open" mode as default.

This option is set to TRUE as the default configuration.  If the old behavior
is preferred, set "defaults.pcm.nonblock" to 0 in /etc/asound.conf.
This commit is contained in:
Takashi Iwai 2006-01-13 11:52:01 +00:00
parent 0e15e6a97a
commit 3d0e3e2517
2 changed files with 38 additions and 2 deletions
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12
src/conf/alsa.conf
View file

@ -53,6 +53,7 @@ defaults.ctl.card 0
defaults.pcm.card 0
defaults.pcm.device 0
defaults.pcm.subdevice -1
defaults.pcm.nonblock 1
defaults.pcm.front.card defaults.pcm.card
defaults.pcm.front.device defaults.pcm.device
defaults.pcm.rear.card defaults.pcm.card
@ -126,10 +127,21 @@ pcm.hw {
name defaults.pcm.subdevice
}
}
@args.SUBDEV {
type integer
default {
@func refer
name defaults.pcm.subdevice
}
}
type hw
card $CARD
device $DEV
subdevice $SUBDEV
nonblock {
@func refer
name defaults.pcm.nonblock
}
}
pcm.plughw {

28
src/pcm/pcm_hw.c
View file

@ -1231,7 +1231,6 @@ int snd_pcm_hw_open(snd_pcm_t **pcmp, const char *name,
}
snd_ctl_close(ctl);
return snd_pcm_hw_open_fd(pcmp, name, fd, mmap_emulation, sync_ptr_ioctl);
_err:
snd_ctl_close(ctl);
return ret;
@ -1245,6 +1244,12 @@ This plugin communicates directly with the ALSA kernel driver. It is a raw
communication without any conversions. The emulation of mmap access can be
optionally enabled, but expect worse latency in the case.
The nonblock option specifies whether the device is opened in a non-blocking
manner. Note that the blocking behavior for read/write access won't be
changed by this option. This influences only on the blocking behavior at
opening the device. If you would like to keep the compatibility with the
older ALSA stuff, turn this option off.
\code
pcm.name {
type hw # Kernel PCM
@ -1253,6 +1258,7 @@ pcm.name {
[subdevice INT] # Subdevice number (default -1: first available)
[mmap_emulation BOOL] # Enable mmap emulation for ro/wo devices
[sync_ptr_ioctl BOOL] # Use SYNC_PTR ioctl rather than the direct mmap access for control structures
[nonblock BOOL] # Force non-blocking open mode
}
\endcode
@ -1285,6 +1291,8 @@ int _snd_pcm_hw_open(snd_pcm_t **pcmp, const char *name,
long card = -1, device = 0, subdevice = -1;
const char *str;
int err, mmap_emulation = 0, sync_ptr_ioctl = 0;
int nonblock = 1; /* non-block per default */
snd_config_for_each(i, next, conf) {
snd_config_t *n = snd_config_iterator_entry(i);
const char *id;
@ -1338,6 +1346,13 @@ int _snd_pcm_hw_open(snd_pcm_t **pcmp, const char *name,
sync_ptr_ioctl = err;
continue;
}
if (strcmp(id, "nonblock") == 0) {
err = snd_config_get_bool(n);
if (err < 0)
continue;
nonblock = err;
continue;
}
SNDERR("Unknown field %s", id);
return -EINVAL;
}
@ -1345,8 +1360,17 @@ int _snd_pcm_hw_open(snd_pcm_t **pcmp, const char *name,
SNDERR("card is not defined");
return -EINVAL;
}
return snd_pcm_hw_open(pcmp, name, card, device, subdevice, stream, mode, mmap_emulation, sync_ptr_ioctl);
err = snd_pcm_hw_open(pcmp, name, card, device, subdevice, stream,
mode | (nonblock ? SND_PCM_NONBLOCK : 0),
mmap_emulation, sync_ptr_ioctl);
if (err < 0)
return err;
if (nonblock && ! (mode & SND_PCM_NONBLOCK))
/* revert to blocking mode for read/write access */
snd_pcm_hw_nonblock(*pcmp, 0);
return 0;
}
#ifndef DOC_HIDDEN
SND_DLSYM_BUILD_VERSION(_snd_pcm_hw_open, SND_PCM_DLSYM_VERSION);
#endif