[pulseaudio-discuss] [RFC PATCH 1/2] pulsecore: sink: force suspend/resume on passthrough transitions

[Arun Raghavan]

On Sun, 3 Sep 2017, at 04:27 PM, Tanu Kaskinen wrote:
> On Sun, 2017-09-03 at 11:32 +0530, Arun Raghavan wrote:
> > On Tue, 29 Aug 2017, at 04:19 AM, Pierre-Louis Bossart wrote:
> > > A race condition prevents the AES non-audio bit from being set
> > > when enabling IEC61937 passthrough on resume with no sink-input
> > > connected (pa_sink_is_passthrough returns false). The non-audio
> > > bit should really be set when opening the sink.
> > > 
> > > Force the sink to suspend/resume when actually entering passthrough
> > > mode, and likewise force a suspend-resume on leaving passthrough mode.
> > > 
> > > Tested with E-AC3 streams which do need the AES bit set for my
> > > Onkyon receiver to detect the format instead of playing it as
> > > PCM.
> > > 
> > > Signed-off-by: Pierre-Louis Bossart
> > > <pierre-louis.bossart at linux.intel.com>
> > > ---
> > 
> > Looks good. Pushed to next.
> 
> I propose reverting this. In the off-list discussion we've been having,
> I raised a concern regarding the approach used here. I'll copy the
> relevant text here:
> 
>     Reopening the device again in pa_sink_enter_passthrough() like you
>     do in your patch may seem like a simple workaround, but it's only
>     simple because you're ignoring the case where pa_sink_suspend()
>     fails. I would guess that suspending can never fail (I didn't
>     check), but unsuspending definitely can. I don't think it's a good
>     idea to ignore failures, but not ignoring the failure also means
>     that pa_sink_input_put() should fail, and currently that function
>     can't fail, and changing that is not simple.
> 
> The bug about setting the AES bit can be fixed by moving the
> pa_sink_update_rate() to happen a bit later, after the sink input has
> been added to pa_sink.inputs. As we discussed, pa_sink_input_rate()
> will then have to be called every time when entering or leaving the
> passthrough mode, even when the sink rate doesn't have to be changed.

I'm working on a patch to replace update_rate() with reconfigure(). In
this, I force reconfigure to happen when either rate or passthrough
status changes. Should be able to send this out soon.

-- Arun