[alsa-devel] ctl_elems hooks with dmix plugin

[Takashi Iwai]

At Thu, 24 Sep 2009 10:05:57 +0200,
I wrote:
> 
> At Wed, 23 Sep 2009 00:55:54 +0530,
> George Kuriakose wrote:
> > 
> > Hi
> > I was trying to use ctl_elems hooks with dmix plugin but figured that
> > this combination doesn't work. Is there any workaround for this.
> > I am trying the following.
> > There are two softvol devices s0 and s1 going through dmix plugins.
> > I wan't to mute s0 when any app opens s1 and unmute s0 when s1 is closed.
> > I am using the below asoundrc file which results in "No card for this PCM" .
> > Any workarounds or any minor change in libasound which will make this work?
> 
> Currently hook plugin doesn't work with dmix/dsnoop.  The problem is
> that it doesn't inherit the result of snd_pcm_info() from the slave
> PCM.  It'd be not too difficult to make it working, though, I guess.

Could you try the patch below?


Takashi

---
diff --git a/src/pcm/pcm_direct.c b/src/pcm/pcm_direct.c
index 82cc126..d9e596e 100644
--- a/src/pcm/pcm_direct.c
+++ b/src/pcm/pcm_direct.c
@@ -591,7 +591,10 @@ int snd_pcm_direct_poll_revents(snd_pcm_t *pcm, struct pollfd *pfds, unsigned in
 
 int snd_pcm_direct_info(snd_pcm_t *pcm, snd_pcm_info_t * info)
 {
-	// snd_pcm_direct_t *dmix = pcm->private_data;
+	snd_pcm_direct_t *dmix = pcm->private_data;
+
+	if (dmix->spcm && !dmix->shmptr->use_server)
+		return snd_pcm_info(dmix->spcm, info);
 
 	memset(info, 0, sizeof(*info));
 	info->stream = pcm->stream;