On Wed, Apr 01, 2009 at 07:16:15PM +0200, Daniel Gl?ckner wrote: > On 04/01/2009 06:48 PM, Mark Brown wrote: > > JOINT_DUPLEX is just a hint to the application about how the card will > Then there needs to be a way for codecs and machines to force this bit if > the PCM driver didn't set it. Ideally, yes, but it's not really important if it's set or not since it's the constraints that actually matter. Like I say, it's just a hint. > IMHO joint duplex is a hack that works only by chance. > Constraints that depend on the configuration of the first stream on open of the > second stream are no longer valid when the first stream is closed. > It is also not possible to add constraints when the first stream has been opened > but not yet configured. There's several existing drivers which do this (the fsl-ssi driver or the wm8903 spring to mind) - I'm planning to provide a helper for it shortly since it's quite a common requirement. There are some races there but they are fairly narrow and the ALSA APIs don't allow them to be closed down; error handling should still be done. _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
