[pulseaudio-discuss] [PATCH] suspend-on-idle: Allow disabling suspending for specific devices

[Tanu Kaskinen]

On Fri, 2013-09-13 at 13:20 +0530, Arun Raghavan wrote:
> On Fri, 2013-08-30 at 15:11 +0200, David Henningsson wrote:
> > On 08/30/2013 09:28 AM, Tanu Kaskinen wrote:
> > > On Fri, 2013-08-30 at 08:16 +0200, David Henningsson wrote:
> > >> On 08/29/2013 04:36 PM, Tanu Kaskinen wrote:
> > >>> Sometimes it would be nice to disable module-suspend-on-idle for
> > >>> specific devices. For me the use case is to keep a HDMI sink running
> > >>> all the time to avoid loss of audio when starting to play a stream to
> > >>> the device (the HDMI receiver eats a bit from the beginning of the
> > >>> stream when the device is opened). This is arguably a hacky solution
> > >>> to the problem, but on the other hand, I think it's very sensible to
> > >>> interpret negative timeout in the module-suspend-on-idle.timeout
> > >>> property as disabling the suspending altogher. This is also how the
> > >>> exit-idle-time configuration option behaves (negative value disables
> > >>> automatic exiting).
> > >>
> > >> Didn't Arun have another solution for a similar problem? Like a sink
> > >> ALWAYS_RUNNING flag or something.
> > > 
> > > Yes, he did. That patch was not merged, and I don't know if Arun plans
> > > to still work on it.
> > > 
> > > Regardless of Arun's solution, I think it makes sense to support
> > > negative value for the module-suspend-on-idle.timeout property to be
> > > consistent with other timeout parameters.
> > > 
> > 
> > Hmm, it looks like there already is a module-suspend-on-idle.timeout
> > property and you're just improving its functionality. Then I would
> > typically prefer this over a new sink flag.
> > 
> > Even better if the module-suspend-on-idle.timeout was documented though...
> > 
> > Arun, would this solve your problem as well? Would it be possible for
> > the two of you to synchronise your efforts?
> 
> Tanu and I discussed this on IRC. I don't think we should use this
> property to do what I was trying to with ALWAYS_RUNNING - the module
> parameters is mechanism, and the always-running-ness is policy. Don't
> want to mix the two.
> 
> That said, I've no objection to what the patch is trying to do, per se
> (i.e. extend/standardise the semantics of a device property that we
> already support).

OK, patch pushed.

For the record, I agree with Arun in that this property shouldn't be
used in the hardware description files (UCM or alsa-mixer files). I
didn't quite understand Arun's explanation about mechanism vs. policy.
My reason for disliking the property is that it's specific to
module-suspend-on-idle, while "idle suspending not recommended" is a
hardware property that shouldn't be tied to any particular module.

-- 
Tanu