On Thu, Jun 09, 2011 at 11:58:23PM -0700, Patrick Lai wrote:
On 4/26/2011 3:18 AM, Mark Brown wrote:
This is roughly the same thing I've been talking about for digital DAPM links. I've got code which runs at the minute but the implementation sucks too much, should be able to pull out some of the preparation work in the next day or so.
Is it possible I can take an early glimpse of implementation? I do have
No, the code ended up colliding with something someone else had done and wasn't worth saving so I just threw it away. However I did get the external interface upstream before I did that - that was the code to support not providing a platform driver for a DAI. What the code did was to look to see if there was a platform driver and if there wasn't it'd add some DAPM nodes and links which would bring up the DAI with no userspace involvement.
use cases that PCM is exchanged between two back-ends. Right now, I need to define DUMMY hostless front-end DAI links to bring up the back-ends. Another query is how hardware parameters is passed to back-end with your design? Not able to choose back-end channel mode
For the initial code they were just inferred from the capabilities of the DAI - all the cases I'm interested in are for interoperation with something that's fixed format at one end of the link so I could punt on that issue. I'd thought about allowing the dai_link to have a set of hw_params settings stored in it which the user would be given an enumeration to select from but hadn't actually done anything concrete with it.
independent of front-end channel mode is a big problem especially if channel mode is more than stereo. DSP is handles upmixing/downmixing happens in our design. Right now, we force channel mode to stereo. So, for the scenario which we just want mono input, we have codec configured to pick up single mic input to both left and right channel. DSP takes average of two channels into mono stream. Once we need to support > 2 channel recording, it's wasteful to go with the same approach if all we want is mono input. Did we talk about this topic
That might be handlable by either of the methods I was suggesting above. Of course depending on the algorithms you're running the DSP may want more mics than it's producing output channels - beam forming or noise cancellation are the obvious examples there.
during workshop? Why is my problem also a concern on OMAP4/ABE?
Do you mean not also a concern? I *believe* OMAP is passing the configuration through to the external DAI using the front end/back end connection so the format gets selected by the app when it does a record, possibly with rewriting through the hook functions in the machine driver.