At Fri, 29 Aug 2008 14:56:33 +0100,
Liam Girdwood wrote:
>
> On Fri, 2008-08-29 at 15:41 +0200, Takashi Iwai wrote:
> > At Fri, 29 Aug 2008 14:16:52 +0100,
> > Liam Girdwood wrote:
>
> > > I'd prefer an addition to our API to handle this more _common_ case
> > > rather than just removing controls.
> > >
> > > Something where we can mark controls as "disabled" so alsamixer and
> > > friends wont render/get them. This would also allow scenario code to
> > > disable relevant mixers and then re-enable when required.
> >
> > Something like below?
> >
> >
> > Takashi
> >
> > diff --git a/sound/core/control.c b/sound/core/control.c
> > index 3c5e746..c6f7062 100644
> > --- a/sound/core/control.c
> > +++ b/sound/core/control.c
> > @@ -410,6 +410,52 @@ int snd_ctl_remove_id(struct snd_card *card, struct snd_ctl_elem_id *id)
> > EXPORT_SYMBOL(snd_ctl_remove_id);
> >
> > /**
> > + * snd_ctl_activate_id - activate/inactivate the control of the given id
> > + * @card: the card instance
> > + * @id: the control id to activate/inactivate
> > + * @active: non-zero to activate
> > + *
> > + * Finds the control instance with the given id, and activate or
> > + * inactivate the control together with notification, if changed.
> > + *
> > + * Returns 0 if unchanged, 1 if changed, or a negative error code on failure.
> > + */
> > +int snd_ctl_activate_id(struct snd_card *card, struct snd_ctl_elem_id *id,
> > + int active)
> > +{
> > + struct snd_kcontrol *kctl;
> > + struct snd_kcontrol_volatile *vd;
> > + unsigned int index_offset;
> > + int ret;
> > +
> > + down_write(&card->controls_rwsem);
> > + kctl = snd_ctl_find_id(card, id);
> > + if (kctl == NULL) {
> > + up_write(&card->controls_rwsem);
> > + return -ENOENT;
> > + }
> > + index_offset = snd_ctl_get_ioff(kctl, &control->id);
> > + vd = &kctl->vd[index_offset];
> > + ret = 0;
> > + if (active) {
> > + if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_INACTIVE))
> > + goto unlock;
> > + vd->access &= ~SNDRV_CTL_ELEM_ACCESS_INACTIVE;
> > + } else {
> > + if (vd->access & SNDRV_CTL_ELEM_ACCESS_INACTIVE)
> > + goto unlock;
> > + vd->access |= SNDRV_CTL_ELEM_ACCESS_INACTIVE;
> > + }
> > + ret = 1;
> > + unlock:
> > + up_write(&card->controls_rwsem);
> > + if (ret)
> > + snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_INFO, id);
> > + return ret;
> > +}
> > +EXPORT_SYMBOL(snd_ctl_activate_id);
> > +
> > +/**
> > * snd_ctl_remove_unlocked_id - remove the unlocked control of the given id and release it
> > * @file: active control handle
> > * @id: the control id to remove
>
> Wow - that was quick !
>
> Yes, exactly :) We can now add this to our machine drivers to disable
> never used controls (for each machine) and also call this when scenario
> changes too.
>
> Even more interestingly, it could also be called by DAPM......
Good to hear that. Just let me know if you need this in the upstream.
I don't want to push such an API addition too early before any use.
FWIW, below is the latest version, found in my sound-unstable tree.
thanks,
Takashi
>From c4ef566498f37140bcef852109e44bea580f4bc8 Mon Sep 17 00:00:00 2001
From: Takashi Iwai <tiwai@xxxxxxx>
Date: Fri, 29 Aug 2008 16:09:01 +0200
Subject: [PATCH] ALSA: Add snd_ctl_activate_id()
Added a new API function snd_ctl_activate_id() for activate / inactivate
the control element dynamically.
Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
diff --git a/include/sound/control.h b/include/sound/control.h
index 4721b4b..6c0002a 100644
--- a/include/sound/control.h
+++ b/include/sound/control.h
@@ -114,6 +114,8 @@ int snd_ctl_add(struct snd_card * card, struct snd_kcontrol * kcontrol);
int snd_ctl_remove(struct snd_card * card, struct snd_kcontrol * kcontrol);
int snd_ctl_remove_id(struct snd_card * card, struct snd_ctl_elem_id *id);
int snd_ctl_rename_id(struct snd_card * card, struct snd_ctl_elem_id *src_id, struct snd_ctl_elem_id *dst_id);
+int snd_ctl_activate_id(struct snd_card * card, struct snd_ctl_elem_id *id,
+ int active);
struct snd_kcontrol *snd_ctl_find_numid(struct snd_card * card, unsigned int numid);
struct snd_kcontrol *snd_ctl_find_id(struct snd_card * card, struct snd_ctl_elem_id *id);
diff --git a/sound/core/control.c b/sound/core/control.c
index 3c5e746..c6f7062 100644
--- a/sound/core/control.c
+++ b/sound/core/control.c
@@ -410,6 +410,52 @@ int snd_ctl_remove_id(struct snd_card *card, struct snd_ctl_elem_id *id)
EXPORT_SYMBOL(snd_ctl_remove_id);
/**
+ * snd_ctl_activate_id - activate/inactivate the control of the given id
+ * @card: the card instance
+ * @id: the control id to activate/inactivate
+ * @active: non-zero to activate
+ *
+ * Finds the control instance with the given id, and activate or
+ * inactivate the control together with notification, if changed.
+ *
+ * Returns 0 if unchanged, 1 if changed, or a negative error code on failure.
+ */
+int snd_ctl_activate_id(struct snd_card *card, struct snd_ctl_elem_id *id,
+ int active)
+{
+ struct snd_kcontrol *kctl;
+ struct snd_kcontrol_volatile *vd;
+ unsigned int index_offset;
+ int ret;
+
+ down_write(&card->controls_rwsem);
+ kctl = snd_ctl_find_id(card, id);
+ if (kctl == NULL) {
+ up_write(&card->controls_rwsem);
+ return -ENOENT;
+ }
+ index_offset = snd_ctl_get_ioff(kctl, &control->id);
+ vd = &kctl->vd[index_offset];
+ ret = 0;
+ if (active) {
+ if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_INACTIVE))
+ goto unlock;
+ vd->access &= ~SNDRV_CTL_ELEM_ACCESS_INACTIVE;
+ } else {
+ if (vd->access & SNDRV_CTL_ELEM_ACCESS_INACTIVE)
+ goto unlock;
+ vd->access |= SNDRV_CTL_ELEM_ACCESS_INACTIVE;
+ }
+ ret = 1;
+ unlock:
+ up_write(&card->controls_rwsem);
+ if (ret)
+ snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_INFO, id);
+ return ret;
+}
+EXPORT_SYMBOL(snd_ctl_activate_id);
+
+/**
* snd_ctl_remove_unlocked_id - remove the unlocked control of the given id and release it
* @file: active control handle
* @id: the control id to remove
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