bcm2835 ALSA driver hardware mixing or mmap?

I want to be able to share the bcm2835 audio among multiple processes. Using the alsa driver alone (latest raspian) fails horribly (lots of crackling/loops/process lockups). I did manage to get it working fairly reliably using PulseAudio after tweaking the buffer settings, however latency is really poor (measured in seconds). I'm not sure if the hardware has native mixing support that the current driver is not properly utilizing? If not the second best solution may be the dmix plugin, which requires mmap support in the driver. Are there plans to add mmap?

[popcornmix]

Patches for mmap support are welcome...

[kripton]

Yes, mmap-support would be nice. If anyone wants to do this, here are some hints:
http://thread.gmane.org/gmane.linux.alsa.devel/50425/focus=50689

In the meantime (and if it suits your needs), you could try running the "jack-audio-connection-kit" on your Pi as described here:
http://www.raspberrypi.org/phpBB3/viewtopic.php?p=196500#p196500
and tell all your applications/processes to use jack (if they support that)

If your applications do not support audio output via jack, you might try this (doing so on my laptop, not tested on the Pi):
http://alsa.opensrc.org/Jack_and_Loopback_device_as_Alsa-to-Jack_bridge
Then you'd basically have:
Your applications -> ALSA loopback (playback) -> via asoundrc -> ALSA loopback (capture) -> alsa_in -> jack -> alsa_out -> bcm2835 ALSA driver -> HDMI or analog output

[martinezjavier]

Hello,

I've this branch that adds mmap support to the ALSA bcm2835 driver. It also has some (IMHO) improvements to the driver.

I'll do a few more tests and send a pull request later today. It would be great if I can have some feedback about them.

Thanks a lot and best regards