Hi ,
I need more help here. I tried looking at the .conf file but I have another requirement here.
Let me put my requirements here. Please suggest me ways to get this done
1. When I get a .prepare call in my driver, I need to know the stream type 2. When I return from that call, I need to send to the user the locally allocated stream id
This is specific to the sound card/ DSP I am developing the driver for. The application is also proprietary. Is this possible at all? Please suggest me ways to do the same.
Thanks, Harsha
-----Original Message----- From: David Dillow [mailto:dave@thedillows.org] Sent: Tuesday, December 09, 2008 6:14 PM To: Harsha, Priya Cc: Clemens Ladisch; alsa-devel@alsa-project.org; Lee Revell Subject: Re: [alsa-devel] question on hardware mixing
On Tue, 2008-12-09 at 14:25 +0530, Harsha, Priya wrote:
If I define mixer controls to switch between each substream, I would not be able to handle multiple streams at time....
Check into the ALSA configuration file syntax -- there are number of things you can do there, like define a 'voice' device that uses hooks to set a control setting (snd_kcontrol) when you open a PCM. You can use that control setting to let your driver know if the PCM channel is being used for voice or audio traffic.
Look at how the EMU10K1 handles surround sound audio in /etc/alsa/cards/EMU10K1.conf
I started to do some similar things for sis7019 surround sound, but they've never made it out of my office due to lack of time/testing HW.
I had asked this in my earlier follow up email as well - can I use snd_pcm_t->private_data to communicate if it's a voice or audio I understand this private_data gets copied to substream->private data which will reach the driver... Am I right here?
I can't answer this specifically, but I believe the answer is in the name -- 'private'. This is for the ALSA system to use, you can hang your own data off a substream using snd_pcm_substream_chip(). Besides, how do you plan on setting it in the snd_pcm_t type?
I think that if you set up some controls, use the config file language, and have your audio apps open a 'voice' device, you can get where you want.
Dave