Re: External PCM plugin SDK

[Takashi Iwai <tiwai@suse.de>]

At Sat, 12 Feb 2005 03:18:27 +0100,
Marcel Holtmann wrote:
> 
> Hi Takashi,
> 
> > > > but I think we still should implement something like init() and exit()
> > > > of the objects. Otherwise it would not be possible to handle this in a
> > > > correct way and we will get memory leaks and unclosed descriptors.
> > > 
> > > We can add the clean up of cached plugin objects (i.e. calling
> > > dlclose) in the existing snd_config_update_free_global().  This
> > > function is supposed to be used for clean up of config tree cache.
> > > 
> > > Each plugin with the keep-alive flag can have functions with
> > > __attribute__((constructor)) and __attribute__((destructor)) for the
> > > purpose above.
> > 
> > The below is a test patch to add the dlobj cache.
> > 
> > It adds a new mode flag to pcm open mode, SND_PCM_KEEP_ALIVE.
> > In xmms, change the call of snd_pcm_open() like:
> > 
> > 	snd_pcm_open(...., SND_PCM_NONBLOCK | SND_PCM_KEEP_ALIVE);
> > 
> > and the dl object will remain alive until
> > snd_config_update_free_global() is called explicitly.
> > 
> > If the plugin needs always keep-alive, a bit more change is needed.
> 
> I personal think that the object caching should be transparent for the
> applications, but I don't have the insides into the ALSA library. If it
> is too hard then this might be a good solution.

I introduced the additional flag just for compatibility.
But, maybe I was too nervous about that.  Basically there is no big
problem to use dl-object cache for all cases.

OK, now the CVS version keeps the dl-objects.


> However I won't have enough time to test this in detail for the next two
> weeks, but the pcm_a2dp plugin is committed to the BlueZ CVS and maybe
> some others want to give it a try.

Has anyone tried?  Any feedback is welcome.


Takashi


-------------------------------------------------------
SF email is sponsored by - The IT Product Guide
Read honest & candid reviews on hundreds of IT Products from real users.
Discover which products truly live up to the hype. Start reading now.
http://ads.osdn.com/?ad_id=6595&alloc_id=14396&op=click