At Mon, 25 May 2009 17:30:19 +0200, Werner Van Belle wrote: > > Hello, > > This is the third time I tried to get information on the same topic but > there has been no response. Since it is crucial for me to get this to > work, I really would appreciate your input. If necssary I can provide > further documentation. The problem is as follows: if a process which > opened a DSP device forks of a new process, then this child will have > the same handle towards the DSP. What I now want to do is to release the > handle in the child without closing the device for the parent as well. > So essentially the sequence below illustrates the problem if one is > unable to 'unlink' a dsp device. > > a- parent process creates and open dsp device > b- parent process forks of a child 1. Child 1 has access to the same dsp > device > c- parent process closes the DSP device > d- client process can no longer write to the DSP device (these are > already odd semantics, but okay, can live with it) > e- parent process forks of a second child. Child 2 has no dsp device > f- Child 2 tries to open the DSP device. This fails because the device, > although closed, is not released yet by Child 1. > > Is this normal behavior ? > > Is there some rigid documentation on the closing and sharing semantics > of pcm devices ? > Is there a way to unlink a device without closing it ? Unlikely. > If this is the wrong mailinglist, then who should I contact regarding > these erratic semantics ? Which API are you using? A simple test case code would be more helpful to demonstrate. But, in general, sharing the same DSP device among different processes don't sound like a good idea... Takashi _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
