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	PCM SUBDEVICE selection enhancements
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					 4 changed files with 83 additions and 15 deletions
				
			
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			@ -29,7 +29,7 @@
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#include "asoundlib.h"
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#define SND_FILE_CONTROL	"/dev/snd/controlC%i"
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#define SND_CTL_VERSION_MAX	SND_PROTOCOL_VERSION(2, 0, 0)
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#define SND_CTL_VERSION_MAX	SND_PROTOCOL_VERSION(2, 0, 1)
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struct snd_ctl {
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	int card;
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			@ -171,29 +171,33 @@ int snd_ctl_pcm_info(snd_ctl_t *handle, int dev, snd_pcm_info_t * info)
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	return 0;
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}
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int snd_ctl_pcm_playback_info(snd_ctl_t *handle, int dev, snd_pcm_playback_info_t * info)
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int snd_ctl_pcm_playback_info(snd_ctl_t *handle, int dev, int subdev, snd_pcm_playback_info_t * info)
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{
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	snd_ctl_t *ctl;
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	ctl = handle;
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	if (!ctl || !info || dev < 0)
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	if (!ctl || !info || dev < 0 || subdev < 0)
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		return -EINVAL;
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	if (ioctl(ctl->fd, SND_CTL_IOCTL_PCM_DEVICE, &dev) < 0)
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		return -errno;
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	if (ioctl(ctl->fd, SND_CTL_IOCTL_PCM_SUBDEVICE, &subdev) < 0)
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		return -errno;
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	if (ioctl(ctl->fd, SND_CTL_IOCTL_PCM_PLAYBACK_INFO, info) < 0)
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		return -errno;
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	return 0;
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}
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int snd_ctl_pcm_capture_info(snd_ctl_t *handle, int dev, snd_pcm_capture_info_t * info)
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int snd_ctl_pcm_capture_info(snd_ctl_t *handle, int dev, int subdev, snd_pcm_capture_info_t * info)
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{
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	snd_ctl_t *ctl;
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	ctl = handle;
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	if (!ctl || !info || dev < 0)
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	if (!ctl || !info || dev < 0 || subdev < 0)
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		return -EINVAL;
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	if (ioctl(ctl->fd, SND_CTL_IOCTL_PCM_DEVICE, &dev) < 0)
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		return -errno;
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	if (ioctl(ctl->fd, SND_CTL_IOCTL_PCM_SUBDEVICE, &subdev) < 0)
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		return -errno;
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	if (ioctl(ctl->fd, SND_CTL_IOCTL_PCM_CAPTURE_INFO, info) < 0)
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		return -errno;
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	return 0;
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			@ -250,7 +254,7 @@ int snd_ctl_pcm_capture_switch_list(snd_ctl_t *handle, int dev, snd_switch_list_
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		return -EINVAL;
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	if (ioctl(ctl->fd, SND_CTL_IOCTL_PCM_DEVICE, &dev) < 0)
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		return -errno;
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	if (ioctl(ctl->fd, SND_CTL_IOCTL_PCM_RSWITCH_LIST, list) < 0)
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	if (ioctl(ctl->fd, SND_CTL_IOCTL_PCM_CSWITCH_LIST, list) < 0)
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		return -errno;
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	return 0;
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}
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			@ -264,7 +268,7 @@ int snd_ctl_pcm_capture_switch_read(snd_ctl_t *handle, int dev, snd_switch_t * s
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		return -EINVAL;
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	if (ioctl(ctl->fd, SND_CTL_IOCTL_PCM_DEVICE, &dev) < 0)
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		return -errno;
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	if (ioctl(ctl->fd, SND_CTL_IOCTL_PCM_RSWITCH_READ, sw) < 0)
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	if (ioctl(ctl->fd, SND_CTL_IOCTL_PCM_CSWITCH_READ, sw) < 0)
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		return -errno;
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	return 0;
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}
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			@ -278,7 +282,21 @@ int snd_ctl_pcm_capture_switch_write(snd_ctl_t *handle, int dev, snd_switch_t *
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		return -EINVAL;
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	if (ioctl(ctl->fd, SND_CTL_IOCTL_PCM_DEVICE, &dev) < 0)
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		return -errno;
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	if (ioctl(ctl->fd, SND_CTL_IOCTL_PCM_RSWITCH_WRITE, sw) < 0)
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	if (ioctl(ctl->fd, SND_CTL_IOCTL_PCM_CSWITCH_WRITE, sw) < 0)
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		return -errno;
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	return 0;
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}
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int snd_ctl_pcm_prefer_subdevice(snd_ctl_t *handle, int dev, int subdev)
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{
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	snd_ctl_t *ctl;
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	ctl = handle;
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	if (!ctl || dev < 0)
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		return -EINVAL;
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	if (ioctl(ctl->fd, SND_CTL_IOCTL_PCM_DEVICE, &dev) < 0)
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		return -errno;
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	if (ioctl(ctl->fd, SND_CTL_IOCTL_PCM_PREFER_SUBDEVICE, &subdev) < 0)
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		return -errno;
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	return 0;
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}
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			@ -35,32 +35,79 @@ struct snd_pcm {
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	int card;
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	int device;
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	int fd;
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	int mode;
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};
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int snd_pcm_open(snd_pcm_t **handle, int card, int device, int mode)
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{
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	int fd, ver;
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	return snd_pcm_open_subdevice(handle, card, device, -1, mode);
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}
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int snd_pcm_open_subdevice(snd_pcm_t **handle, int card, int device, int subdevice, int mode)
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{
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	int fd, ver, err, attempt = 0;
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	char filename[32];
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	snd_pcm_t *pcm;
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	snd_ctl_t *ctl;
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	snd_pcm_playback_info_t pinfo;
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	snd_pcm_capture_info_t cinfo;
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	*handle = NULL;
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	if (card < 0 || card >= SND_CARDS)
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		return -EINVAL;
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	if ((err = snd_ctl_open(&ctl, card)) < 0)
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		return err;
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      __again:
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      	if (attempt++ > 3) {
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      		snd_ctl_close(ctl);
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      		return -EBUSY;
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      	}
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	if ((err = snd_ctl_pcm_prefer_subdevice(ctl, device, subdevice)) < 0) {
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		snd_ctl_close(ctl);
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		return err;
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	}
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	sprintf(filename, SND_FILE_PCM, card, device);
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	if ((fd = open(filename, mode)) < 0) {
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		snd_card_load(card);
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		if ((fd = open(filename, mode)) < 0) 
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			return -errno;
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		err = -errno;
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		snd_ctl_close(ctl);
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		return err;
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	}
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	if (ioctl(fd, SND_PCM_IOCTL_PVERSION, &ver) < 0) {
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		err = -errno;
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		close(fd);
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		return -errno;
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		snd_ctl_close(ctl);
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		return err;
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	}
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	if (SND_PROTOCOL_INCOMPATIBLE(ver, SND_PCM_VERSION_MAX)) {
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		close(fd);
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		snd_ctl_close(ctl);
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		return -SND_ERROR_INCOMPATIBLE_VERSION;
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	}
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	if (subdevice >= 0 && (mode == SND_PCM_OPEN_PLAYBACK || mode == SND_PCM_OPEN_DUPLEX)) {
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		if (ioctl(fd, SND_PCM_IOCTL_PLAYBACK_INFO, &pinfo) < 0) {
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			err = -errno;
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			close(fd);
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			snd_ctl_close(ctl);
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			return err;
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		}
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		if (pinfo.subdevice != subdevice) {
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			close(fd);
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			goto __again;
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		}
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	}
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	if (subdevice >= 0 && (mode == SND_PCM_OPEN_CAPTURE || mode == SND_PCM_OPEN_DUPLEX)) {
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		if (ioctl(fd, SND_PCM_IOCTL_CAPTURE_INFO, &cinfo) < 0) {
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			err = -errno;
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			close(fd);
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			snd_ctl_close(ctl);
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			return err;
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		}
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		if (cinfo.subdevice != subdevice) {
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			close(fd);
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			goto __again;
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		}
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	}
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	pcm = (snd_pcm_t *) calloc(1, sizeof(snd_pcm_t));
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	if (pcm == NULL) {
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		close(fd);
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			@ -69,6 +116,7 @@ int snd_pcm_open(snd_pcm_t **handle, int card, int device, int mode)
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	pcm->card = card;
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	pcm->device = device;
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	pcm->fd = fd;
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	pcm->mode = mode;
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	*handle = pcm;
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	return 0;
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}
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