On Thu, 2016-04-21 at 12:26 +0530, Arun Raghavan wrote: > On 22 March 2016 at 19:11, Tanu Kaskinen <tanuk at iki.fi> wrote: > > > > Before a device is unlinked, the unlink hook is fired, and it's > > possible that a routing module tries to move streams to the unlinked > > device in that hook, because it doesn't know that the device is being > > unlinked. Of course, the unlinking is obvious when the code is in an > > unlink hook callback, but it's possible that some other module does > > something in the unlink hook that in turn triggers some other hook, > > and it's this second hook where the routing module may get confused. > > This patch adds an "unlink_requested" flag that is set before the > > unlink hook is fired, and moving streams to a device with that flag > > set is prevented. > > > > This patch is motivated by seeing module-device-manager moving a > > stream to a sink that was being unlinked. It was a complex case where > > an alsa card was changing its profile, while an echo-cancel sink was > > connected to the old alsa sink. module-always-sink loaded a null sink > > in the middle of the profile change, and after a stream had been > > rescued to the null sink, module-device-manager decided to move it > > back to the old alsa sink that was being unlinked. That move made no > > sense, so I came up with this patch. > > --- > I think this is a good solution to the problem. Still need to test > this in a few use cases, but it makes sense to me too. > > I also think that it might be nicer to have this be a part of the > state enum rather than a separate bool. What do you think? I'm okay to > make that change quickly if you don't want to, fwiw. I considered that, but I don't think it's a good idea, because in the "unlink requested" state the sink is still fully operational, and it can be running, idle or suspended. Adding a new state would hide the separation between those states. --Â Tanu
