On Fri, Apr 03, 2009 at 01:56:47PM +0200, Lennart Poettering wrote: > On Fri, 03.04.09 09:38, Clemens Ladisch (clemens@xxxxxxxxxx) wrote: > > > > - dynamic device creation at runtime - for example we have an > > > experimental HDA driver configuration code which might change > > > the arrangement of PCM devices on request from the user space > > > > > > I would suggest to wait awhile with some small timeout (0.5 sec?) for all > > > devices to get the usual static arrangement working and handle extra > > > dynamic cases, too. > > > > The current implementation of the ALSA framework guarantees that the > > control device file is that latest one to be created for all the devices > > created at initialization. Any devices created later depend on some > > userspace action, so a small timeout won't help in this case. > > > > In other words: > > 1) When the control device file has been created, all other devices > > (that are created during sound card initialization) are > > available. > > OK. Very good. I'll then change PA to rely on this behaviour and hope > that this is considered part of the ALSA userspace API and is not > changed in the future... > > > 2) When some device file for a specific sound card is created after the > > card's control device, the sound card configuration has changed. > > I'll ignore this for now since Jaroslav mentioned drivers doing this > are still experimental. But eventually we'd need to know some kind of > 'end notification' for this as well: i..e if the reconfiguration > causes multiple device nodes to disappear/appear we also need to know > when they are all complete. A possible simple fix would be to issue an > udev 'change' event on the control device after the reconfiguration > finished. btw, HDMI sink devices could be taught to generate more event types: - hotplug The user connected/disconnected a HDMI device. - reconfiguration The update of HDMI audio capabilities due to some user actions. - pause/play of audio stream An advanced feature in Consumer Electronics Control (CEC) for high-level user control of HDMI-connected devices. The HDMI audio devices will be created at module loading time, and won't be dynamically created/tear down on hotplug events. I wonder if PA is interested in the HDMI current-connectivity state? Thanks, Fengguang _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
