From f5b1db634280ecaf3147ee996f26aad0ed4828c4 Mon Sep 17 00:00:00 2001 From: Takashi Iwai Date: Fri, 16 Jan 2009 18:15:22 +0100 Subject: ALSA: add snd_ctl_add_slave_uncached() Added snd_ctl_add_slave_uncached() function to add a slave element with volatile controls. The values of normal slave elements are supposed to be cachable, i.e. they are changed only via the put callbacks. OTOH, when a slave element is volatile and its values may be changed by other reason (e.g. hardware status change), the values will get inconsistent. The new function allows the slave elements with volatile changes. When the slave is tied with this call, the native get callback is issued at each time so that the values are always updated. Signed-off-by: Takashi Iwai --- sound/core/vmaster.c | 46 +++++++++++++++++++++++++++++----------------- 1 file changed, 29 insertions(+), 17 deletions(-) (limited to 'sound/core') diff --git a/sound/core/vmaster.c b/sound/core/vmaster.c index 4cc57f902e2c..d51b198d06d9 100644 --- a/sound/core/vmaster.c +++ b/sound/core/vmaster.c @@ -50,18 +50,38 @@ struct link_slave { struct link_master *master; struct link_ctl_info info; int vals[2]; /* current values */ + unsigned int flags; struct snd_kcontrol slave; /* the copy of original control entry */ }; +static int slave_update(struct link_slave *slave) +{ + struct snd_ctl_elem_value *uctl; + int err, ch; + + uctl = kmalloc(sizeof(*uctl), GFP_KERNEL); + if (!uctl) + return -ENOMEM; + uctl->id = slave->slave.id; + err = slave->slave.get(&slave->slave, uctl); + for (ch = 0; ch < slave->info.count; ch++) + slave->vals[ch] = uctl->value.integer.value[ch]; + kfree(uctl); + return 0; +} + /* get the slave ctl info and save the initial values */ static int slave_init(struct link_slave *slave) { struct snd_ctl_elem_info *uinfo; - struct snd_ctl_elem_value *uctl; - int err, ch; + int err; - if (slave->info.count) - return 0; /* already initialized */ + if (slave->info.count) { + /* already initialized */ + if (slave->flags & SND_CTL_SLAVE_NEED_UPDATE) + return slave_update(slave); + return 0; + } uinfo = kmalloc(sizeof(*uinfo), GFP_KERNEL); if (!uinfo) @@ -85,15 +105,7 @@ static int slave_init(struct link_slave *slave) slave->info.max_val = uinfo->value.integer.max; kfree(uinfo); - uctl = kmalloc(sizeof(*uctl), GFP_KERNEL); - if (!uctl) - return -ENOMEM; - uctl->id = slave->slave.id; - err = slave->slave.get(&slave->slave, uctl); - for (ch = 0; ch < slave->info.count; ch++) - slave->vals[ch] = uctl->value.integer.value[ch]; - kfree(uctl); - return 0; + return slave_update(slave); } /* initialize master volume */ @@ -229,7 +241,8 @@ static void slave_free(struct snd_kcontrol *kcontrol) * - logarithmic volume control (dB level), no linear volume * - master can only attenuate the volume, no gain */ -int snd_ctl_add_slave(struct snd_kcontrol *master, struct snd_kcontrol *slave) +int _snd_ctl_add_slave(struct snd_kcontrol *master, struct snd_kcontrol *slave, + unsigned int flags) { struct link_master *master_link = snd_kcontrol_chip(master); struct link_slave *srec; @@ -241,6 +254,7 @@ int snd_ctl_add_slave(struct snd_kcontrol *master, struct snd_kcontrol *slave) srec->slave = *slave; memcpy(srec->slave.vd, slave->vd, slave->count * sizeof(*slave->vd)); srec->master = master_link; + srec->flags = flags; /* override callbacks */ slave->info = slave_info; @@ -254,8 +268,7 @@ int snd_ctl_add_slave(struct snd_kcontrol *master, struct snd_kcontrol *slave) list_add_tail(&srec->list, &master_link->slaves); return 0; } - -EXPORT_SYMBOL(snd_ctl_add_slave); +EXPORT_SYMBOL(_snd_ctl_add_slave); /* * ctl callbacks for master controls @@ -367,5 +380,4 @@ struct snd_kcontrol *snd_ctl_make_virtual_master(char *name, return kctl; } - EXPORT_SYMBOL(snd_ctl_make_virtual_master); -- cgit v1.2.3 From 79c7cdd5441f5d3900c1632adcc8cd2bee35c8da Mon Sep 17 00:00:00 2001 From: Takashi Iwai Date: Mon, 9 Feb 2009 14:47:19 +0100 Subject: ALSA: Add kernel-doc comments to vmaster stuff Signed-off-by: Takashi Iwai --- .../sound/alsa/DocBook/alsa-driver-api.tmpl | 4 +++ include/sound/control.h | 32 ++++++++++++++++++++++ sound/core/vmaster.c | 16 +++++++++-- 3 files changed, 50 insertions(+), 2 deletions(-) (limited to 'sound/core') diff --git a/Documentation/sound/alsa/DocBook/alsa-driver-api.tmpl b/Documentation/sound/alsa/DocBook/alsa-driver-api.tmpl index 9d644f7e241e..115962827c81 100644 --- a/Documentation/sound/alsa/DocBook/alsa-driver-api.tmpl +++ b/Documentation/sound/alsa/DocBook/alsa-driver-api.tmpl @@ -71,6 +71,10 @@ !Esound/pci/ac97/ac97_codec.c !Esound/pci/ac97/ac97_pcm.c + Virtual Master Control API +!Esound/core/vmaster.c +!Iinclude/sound/control.h + MIDI API Raw MIDI API diff --git a/include/sound/control.h b/include/sound/control.h index 4cf8f7aaa13f..ef96f07aa03b 100644 --- a/include/sound/control.h +++ b/include/sound/control.h @@ -176,12 +176,44 @@ int _snd_ctl_add_slave(struct snd_kcontrol *master, struct snd_kcontrol *slave, /* optional flags for slave */ #define SND_CTL_SLAVE_NEED_UPDATE (1 << 0) +/** + * snd_ctl_add_slave - Add a virtual slave control + * @master: vmaster element + * @slave: slave element to add + * + * Add a virtual slave control to the given master element created via + * snd_ctl_create_virtual_master() beforehand. + * Returns zero if successful or a negative error code. + * + * All slaves must be the same type (returning the same information + * via info callback). The fucntion doesn't check it, so it's your + * responsibility. + * + * Also, some additional limitations: + * at most two channels, + * logarithmic volume control (dB level) thus no linear volume, + * master can only attenuate the volume without gain + */ static inline int snd_ctl_add_slave(struct snd_kcontrol *master, struct snd_kcontrol *slave) { return _snd_ctl_add_slave(master, slave, 0); } +/** + * snd_ctl_add_slave_uncached - Add a virtual slave control + * @master: vmaster element + * @slave: slave element to add + * + * Add a virtual slave control to the given master. + * Unlike snd_ctl_add_slave(), the element added via this function + * is supposed to have volatile values, and get callback is called + * at each time quried from the master. + * + * When the control peeks the hardware values directly and the value + * can be changed by other means than the put callback of the element, + * this function should be used to keep the value always up-to-date. + */ static inline int snd_ctl_add_slave_uncached(struct snd_kcontrol *master, struct snd_kcontrol *slave) diff --git a/sound/core/vmaster.c b/sound/core/vmaster.c index d51b198d06d9..257624bd1997 100644 --- a/sound/core/vmaster.c +++ b/sound/core/vmaster.c @@ -340,8 +340,20 @@ static void master_free(struct snd_kcontrol *kcontrol) } -/* - * Create a virtual master control with the given name +/** + * snd_ctl_make_virtual_master - Create a virtual master control + * @name: name string of the control element to create + * @tlv: optional TLV int array for dB information + * + * Creates a virtual matster control with the given name string. + * Returns the created control element, or NULL for errors (ENOMEM). + * + * After creating a vmaster element, you can add the slave controls + * via snd_ctl_add_slave() or snd_ctl_add_slave_uncached(). + * + * The optional argument @tlv can be used to specify the TLV information + * for dB scale of the master control. It should be a single element + * with #SNDRV_CTL_TLVT_DB_SCALE type, and should be the max 0dB. */ struct snd_kcontrol *snd_ctl_make_virtual_master(char *name, const unsigned int *tlv) -- cgit v1.2.3