[pulseaudio-discuss] Using pulseaudio with speakup

[Markus Rechberger]

On Sat, Jan 2, 2010 at 2:17 PM, Colin Guthrie <gmane at colin.guthr.ie> wrote:
> 'Twas brillig, and Bill Cox at 01/01/10 21:58 did gyre and gimble:
>> However, even with these changes, there are bugs due to pulseaudio's
>> user-based structure.  Today, in Karmic, if I 'switch user' to another
>> use, my new gnome session has no sound.  That's because there are two
>> pulseaudio processes running, and the first one takes over control of
>> the sound card and does not share.
>
> Other folk have replied now but just to explain in detail for clarity:
>
> It is by design that multiple pulseaudio processes run at the same time
> but the idea is that they gracefully drop access to the actual sound
> hardware when the given user is not supposed to have access. This is why
> the gdm user has direct access at the login window and then when a user
> logs in it gracefully hands control over to the real user. Again
> switching users should all just work.
>
> PA should remain running even when the user does not have current access
> to the hardware as it will "cork" it's streams (a sort of equivalent to
> pause) and as more applications are aware of the concept of corking they
> will be able to adjust their UI accordingly. We can also issue corks for
> other reasons (e.g. a voip call comes in so the music and video apps are
> corked/paused.

In practice did you test this with some mpeg players? I wonder if they
will automatically pause the
Video. Video is usually synced against audio as you might know.
It should not make any problem with mpeg videos but how about live video.
Unless the application starts to timeshift by itself PA will take care
that the livestream will become corrupted.
Does this corking mechanism really just pause the readout of the
audiosamples? - I see quite some problems if
it does so.

Markus

>
> So whatever problem you are having switching users would seem to suggest
> a problem with consolekit and/or the consolekit module in PA.
>
> Use the program ck-list-sessions to see which user is currently "active"
> to debug this further.
>
> Daniel's earlier comments about the different users are the wait forward
> to debug further.
>
> Col
>
> --
>
> Colin Guthrie
> gmane(at)colin.guthr.ie
> http://colin.guthr.ie/
>
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