[alsa-devel] [PATCH] alsa-lib: snd_device_name_hint misbehaving

John Lindgren john.lindgren at tds.net
Mon Nov 2 18:58:20 CET 2009


On Mon, 2009-11-02 at 15:55 +0100, Takashi Iwai wrote:
> Thanks.  I guess this depends on the config files.
> Could you attach your ones?

I can reproduce with only the stock /usr/share/alsa/alsa.conf from
Debian installed if I try to use the "null" device after
snd_device_name_hint.  /usr/share/alsa/alsa.conf is attached.

------

#include <stdio.h>
#include <alsa/asoundlib.h>

void try_open (const char * pcm)
{
    snd_pcm_t * handle;
    int error;

    error = snd_pcm_open (& handle, pcm, SND_PCM_STREAM_PLAYBACK, 0);

    if (error < 0)
        printf ("Failed to open %s: %s.\n", pcm, snd_strerror (error));
    else
    {
        printf ("Opened %s.\n", pcm);
        snd_pcm_close (handle);
    }
}

int main (void)
{
    void * * hints;

    try_open ("default");
    try_open ("null");
    try_open ("default");
    try_open ("null");

    printf ("Calling snd_device_name_hint().\n");
    snd_device_name_hint (-1, "pcm", & hints);
    snd_device_name_free_hint (hints);

    try_open ("default");
    try_open ("null");
    try_open ("default");
    try_open ("null");

    return 0;
}

------

$ ./pcmtest 
Opened default.
Opened null.
Opened default.
Opened null.
Calling snd_device_name_hint().
Opened default.
ALSA lib pcm.c:2211:(snd_pcm_open_noupdate) Unknown PCM null
Failed to open null: No such file or directory.
Opened default.
ALSA lib pcm.c:2211:(snd_pcm_open_noupdate) Unknown PCM null
Failed to open null: No such file or directory.
-------------- next part --------------
#
#  ALSA library configuration file
#

# pre-load the configuration files

@hooks [
	{
		func load
		files [
			"/etc/asound.conf"
			"~/.asoundrc"
		]
		errors false
	}
]

# load card-specific configuration files (on request)

cards. at hooks [
	{
		func load
		files [
			{
				@func concat
				strings [
					{ @func datadir }
					"/cards/aliases.conf"
				]
			}
		]
	}
	{
		func load_for_all_cards
		files [
			{
				@func concat
				strings [
					{ @func datadir }
					"/cards/"
					{ @func private_string }
					".conf"
				]
			}
		]
		errors false
	}
]

#
# defaults
#

# show all name hints also for definitions without hint {} section
defaults.namehint.showall off
# show just basic name hints
defaults.namehint.basic on
# show extended name hints
defaults.namehint.extended off
#
defaults.ctl.card 0
defaults.pcm.card 0
defaults.pcm.device 0
defaults.pcm.subdevice -1
defaults.pcm.nonblock 1
defaults.pcm.ipc_key 5678293
defaults.pcm.ipc_gid audio
defaults.pcm.ipc_perm 0660
defaults.pcm.dmix.max_periods 0
defaults.pcm.dmix.rate 48000
defaults.pcm.dmix.format "unchanged"
defaults.pcm.dmix.card defaults.pcm.card
defaults.pcm.dmix.device defaults.pcm.device
defaults.pcm.dsnoop.card defaults.pcm.card
defaults.pcm.dsnoop.device defaults.pcm.device
defaults.pcm.front.card defaults.pcm.card
defaults.pcm.front.device defaults.pcm.device
defaults.pcm.rear.card defaults.pcm.card
defaults.pcm.rear.device defaults.pcm.device
defaults.pcm.center_lfe.card defaults.pcm.card
defaults.pcm.center_lfe.device defaults.pcm.device
defaults.pcm.side.card defaults.pcm.card
defaults.pcm.side.device defaults.pcm.device
defaults.pcm.surround40.card defaults.pcm.card
defaults.pcm.surround40.device defaults.pcm.device
defaults.pcm.surround41.card defaults.pcm.card
defaults.pcm.surround41.device defaults.pcm.device
defaults.pcm.surround50.card defaults.pcm.card
defaults.pcm.surround50.device defaults.pcm.device
defaults.pcm.surround51.card defaults.pcm.card
defaults.pcm.surround51.device defaults.pcm.device
defaults.pcm.surround71.card defaults.pcm.card
defaults.pcm.surround71.device defaults.pcm.device
defaults.pcm.iec958.card defaults.pcm.card
defaults.pcm.iec958.device defaults.pcm.device
defaults.pcm.modem.card defaults.pcm.card
defaults.pcm.modem.device defaults.pcm.device
# truncate files via file or tee PCM
defaults.pcm.file_format	"raw"
defaults.pcm.file_truncate	true
defaults.rawmidi.card 0
defaults.rawmidi.device 0
defaults.rawmidi.subdevice -1
defaults.hwdep.card 0
defaults.hwdep.device 0
defaults.timer.class 2
defaults.timer.sclass 0
defaults.timer.card 0
defaults.timer.device 0
defaults.timer.subdevice 0

#
#  PCM interface
#

# redirect to load-on-demand extended pcm definitions
pcm.cards cards.pcm

pcm.default cards.pcm.default
pcm.front cards.pcm.front
pcm.rear cards.pcm.rear
pcm.center_lfe cards.pcm.center_lfe
pcm.side cards.pcm.side
pcm.surround40 cards.pcm.surround40
pcm.surround41 cards.pcm.surround41
pcm.surround50 cards.pcm.surround50
pcm.surround51 cards.pcm.surround51
pcm.surround71 cards.pcm.surround71
pcm.iec958 cards.pcm.iec958
pcm.spdif iec958
pcm.hdmi cards.pcm.hdmi
pcm.dmix cards.pcm.dmix
pcm.dsnoop cards.pcm.dsnoop
pcm.modem cards.pcm.modem
pcm.phoneline cards.pcm.phoneline

pcm.hw {
	@args [ CARD DEV SUBDEV ]
	@args.CARD {
		type string
		default {
			@func getenv
			vars [
				ALSA_PCM_CARD
				ALSA_CARD
			]
			default {
				@func refer
				name defaults.pcm.card
			}
		}
	}
	@args.DEV {
		type integer
		default {
			@func igetenv
			vars [
				ALSA_PCM_DEVICE
			]
			default {
				@func refer
				name defaults.pcm.device
			}
		}
	}
	@args.SUBDEV {
		type integer
		default {
			@func refer
			name defaults.pcm.subdevice
		}
	}		
	type hw
	card $CARD
	device $DEV
	subdevice $SUBDEV
	hint {
		show {
			@func refer
			name defaults.namehint.extended
		}
		description "Direct hardware device without any conversions"
	}
}

pcm.plughw {
	@args [ CARD DEV SUBDEV ]
	@args.CARD {
		type string
		default {
			@func getenv
			vars [
				ALSA_PCM_CARD
				ALSA_CARD
			]
			default {
				@func refer
				name defaults.pcm.card
			}
		}
	}
	@args.DEV {
		type integer
		default {
			@func igetenv
			vars [
				ALSA_PCM_DEVICE
			]
			default {
				@func refer
				name defaults.pcm.device
			}
		}
	}
	@args.SUBDEV {
		type integer
		default {
			@func refer
			name defaults.pcm.subdevice
		}
	}		
	type plug
	slave.pcm {
		type hw
		card $CARD
		device $DEV
		subdevice $SUBDEV
	}
	hint {
		show {
			@func refer
			name defaults.namehint.extended
		}
		description "Hardware device with all software conversions"
	}
}

pcm.plug {
	@args [ SLAVE ]
	@args.SLAVE {
		type string
	}
	type plug
	slave.pcm $SLAVE
}

pcm.shm {
	@args [ SOCKET PCM ]
	@args.SOCKET {
		type string
	}
	@args.PCM {
		type string
	}
	type shm
	server $SOCKET
	pcm $PCM
}

pcm.tee {
	@args [ SLAVE FILE FORMAT ]
	@args.SLAVE {
		type string
	}
	@args.FILE {
		type string
	}
	@args.FORMAT {
		type string
		default {
			@func refer
			name defaults.pcm.file_format
		}
	}
	type file
	slave.pcm $SLAVE
	file $FILE
	format $FORMAT
	truncate {
		@func refer
		name defaults.pcm.file_truncate
	}
}

pcm.file {
	@args [ FILE FORMAT ]
	@args.FILE {
		type string
	}
	@args.FORMAT {
		type string
		default {
			@func refer
			name defaults.pcm.file_format
		}
	}
	type file
	slave.pcm null
	file $FILE
	format $FORMAT
	truncate {
		@func refer
		name defaults.pcm.file_truncate
	}
}

pcm.null {
	type null
	hint {
		show {
			@func refer
			name defaults.namehint.basic
		}
		description "Discard all samples (playback) or generate zero samples (capture)"
	}
}

#
#  Control interface
#
	
ctl.default {
	type hw
	card {
		@func getenv
		vars [
			ALSA_CTL_CARD
			ALSA_CARD
		]
		default {
			@func refer
			name defaults.ctl.card
		}
	}
}

ctl.hw {
	@args [ CARD ]
	@args.CARD {
		type string
		default {
			@func getenv
			vars [
				ALSA_CTL_CARD
				ALSA_CARD
			]
			default {
				@func refer
				name defaults.ctl.card
			}
		}
	}
	type hw
	card $CARD
}

ctl.shm {
	@args [ SOCKET CTL ]
	@args.SOCKET {
		type string
	}
	@args.CTL {
		type string
	}
	type shm
	server $SOCKET
	ctl $CTL
}

#
#  RawMidi interface
#

rawmidi.default {
	type hw
	card {
		@func getenv
		vars [
			ALSA_RAWMIDI_CARD
			ALSA_CARD
		]
		default {
			@func refer
			name defaults.rawmidi.card
		}
	}
	device {
		@func igetenv
		vars [
			ALSA_RAWMIDI_DEVICE
		]
		default {
			@func refer
			name defaults.rawmidi.device
		}
	}
}

rawmidi.hw {
	@args [ CARD DEV SUBDEV ]
	@args.CARD {
		type string
		default {
			@func getenv
			vars [
				ALSA_RAWMIDI_CARD
				ALSA_CARD
			]
			default {
				@func refer
				name defaults.rawmidi.card
			}
		}
	}
	@args.DEV {
		type integer
		default {
			@func igetenv
			vars [
				ALSA_RAWMIDI_DEVICE
			]
			default {
				@func refer
				name defaults.rawmidi.device
			}
		}
	}
	@args.SUBDEV {
		type integer
		default -1
	}
	type hw
	card $CARD
	device $DEV
	subdevice $SUBDEV
	hint {
		description "Direct rawmidi driver device"
		device $DEV
	}
}

rawmidi.virtual {
	@args [ MERGE ]
	@args.MERGE {
		type string
		default 1
	}
	type virtual
	merge $MERGE
}

#
#  Sequencer interface
#

seq.default {
	type hw
}

seq.hw {
	type hw
}

#
#  HwDep interface
#

hwdep.default {
	type hw
	card {
		@func getenv
		vars [
			ALSA_HWDEP_CARD
			ALSA_CARD
		]
		default {
			@func refer
			name defaults.hwdep.card
		}
	}
	device {
		@func igetenv
		vars [
			ALSA_HWDEP_DEVICE
		]
		default {
			@func refer
			name defaults.hwdep.device
		}
	}
}

hwdep.hw {
	@args [ CARD DEV ]
	@args.CARD {
		type string
		default {
			@func getenv
			vars [
				ALSA_HWDEP_CARD
				ALSA_CARD
			]
			default {
				@func refer
				name defaults.hwdep.card
			}
		}
	}
	@args.DEV {
		type integer
		default {
			@func igetenv
			vars [
				ALSA_HWDEP_DEVICE
			]
			default {
				@func refer
				name defaults.hwdep.device
			}
		}
	}
	type hw
	card $CARD
	device $DEV
}

#
#  Timer interface
#

timer_query.default {
	type hw
}

timer_query.hw {
	type hw
}

timer.default {
	type hw
	class {
		@func refer
		name defaults.timer.class
	}
	sclass {
		@func refer
		name defaults.timer.sclass
	}
	card {
		@func refer
		name defaults.timer.card
	}
	device {
		@func refer
		name defaults.timer.device
	}
	subdevice {
		@func refer
		name defaults.timer.subdevice
	}
	hint.description "Default direct hardware timer device"
}

timer.hw {
	@args [ CLASS SCLASS CARD DEV SUBDEV ]
	@args.CLASS {
		type integer
		default {
			@func refer
			name defaults.timer.class
		}
	}
	@args.SCLASS {
		type integer
		default {
			@func refer
			name defaults.timer.sclass
		}
	}
	@args.CARD {
		type string
		default {
			@func refer
			name defaults.timer.card
		}
	}
	@args.DEV {
		type integer
		default {
			@func refer
			name defaults.timer.device
		}
	}
	@args.SUBDEV {
		type integer
		default {
			@func refer
			name defaults.timer.subdevice
		}
	}
	type hw
	class $CLASS
	sclass $SCLASS
	card $CARD
	device $DEV
	subdevice $SUBDEV
}


More information about the Alsa-devel mailing list