[alsa-devel] Ambiguous DAPM widget names and DPCM

Mark Brown broonie at kernel.org
Thu Jul 25 14:48:59 CEST 2013

On Thu, Jul 25, 2013 at 02:24:54PM +0200, Daniel Mack wrote:
> On 23.07.2013 20:30, Mark Brown wrote:
> > On Tue, Jul 23, 2013 at 05:34:59PM +0200, Daniel Mack wrote:

> > OK, so the issue here is probably that you're overloading the single
> > McASP object rather than anything else

> Hmm, I'm not following. Isn't that the way things are supposed to work
> with DPCM?

Not normally - normally there's a single CODEC on each external
interface with multiple front ends connected to it.

> > Lookups are done first in the local DAPM context so so long as the thing
> > that's setting up the links is doing so in the same context everything
> > should be OK.  This is needed so you can have two of the same device in
> > a system.

> Hmm, but DPCM does not have such a local context, and just tries to look
> up the widgets by name globally.

OK, so this is probably something that needs to be looked at.

> > The prefix mechanism is intended to address this; however it's only
> > currently supported for CODECs.  If we move the prefixes to components
> > then they should be usable for CPU DAIs.

> But that's a static string as well. How can we distiguish between two
> Codecs of the same type, or two McASP instances?

The point is to give a different prefix to each device; giving the same
prefix to different devices rather defeats the poinnt.
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 836 bytes
Desc: Digital signature
URL: <http://mailman.alsa-project.org/pipermail/alsa-devel/attachments/20130725/1164a911/attachment.sig>

More information about the Alsa-devel mailing list