Re: [ladcca] Problems with LASH

[Dave Robillard]

On Tue, 2005-31-05 at 23:05 +0100, Bob Ham wrote:
> On Sat, 2005-05-28 at 13:10 +1000, Dave Robillard wrote:
> > Hi all,
> > 
> > Seems there hasn't been a post to this list in almost a year.  Hope
> > someone is still listening.  Anyway..
> 
> Still listening, just tied up.  As noted, I've been very quiet for the
> past year.  I wish I could say I've been quietly working on LASH, but in
> fact I've been just about treading water with my first job.  It's a hard
> life, etc.  Regardless, I've recently been trying to bring linux audio
> back into my sights, and succeeding to a small degree.  However, I've
> more recently made the decision to return to university, and that goal
> conflicts with working as energetically on LASH as is necessary for it
> to move in more useful directions.
> 
> I've already passed the baton on with JACK Rack; Leslie Patrick Polzer
> is now the official maintainer; I'm sure there will be announcements and
> new URLs and whatnot once a release is made.
> 
> As for LASH, nobody has asked to take over maintainership of it.  It
> would be a shame in my, perhaps ever-so-slightly biased opinion to let
> it rot, so I ask if anybody would care to take the reins?
> 
> I'll still be around, and I'm still a linux audio user, so I certainly
> have a vested interest in helping where I can, it's just the amount I
> can help is a lot less than LASH needs :(

If I find out what is wrong with LASH, I mean to fix it myself.  If
you're too busy to accept patches and make releases and all that, I can
take over.  It doesn't seem like a whole lot of work is involved in
maintaining LASH, so I'm up for it.  I just need it to work, whatever
the process :)

FWIW I never managed to actually check out the SVN repository.

> > I'm trying to implement Lash support in an app of mine, but I'm having a
> > problem with restoring.  Lash launches my app alright, but sometimes I
> > get this message from ladccad:
> > 
> > conn_mgr_send_server_event_to_client: could not send event to unknown
> > connection id 10
> > 
> > And my app doesn't receive any of it's events.  Sometimes this happens,
> > and sometimes everything works fine - completely random.  It seems like
> > maybe a timing issue, but surely Lash must wait for the client to call
> > cca_init before attempting to send it events?
> > 
> > The very next line from ladccad is:
> > 
> > ladcca.c:186:cca_init: connected to server
> > 
> > So I thought maybe I needed to call cca_init sooner in my app (which
> > would be a braindead thing to have to do..) but that didn't work either.
> 
> This is very strange; the client doesn't exist from the server's
> perspective until it calls cca_init, except in a ghosted state, and I
> don't think it's even possible for it to send events to those clients.
> The fact that it thinks there's a connection with an ID of 10 makes me
> think that wires are getting crossed with a different client.  I would
> offer to take a look at it, but I don't have a LASH development
> environment set up at the moment.

I think that's the exact problem - it /doesn't/ think there's a client
with connection ID 10.  I havn't had time to look at the lash code
throughly yet, but I assume what is happening is:

- User asks lash to restore a session
- Lash laucnhes app with ID 10
- Lash sends events to ID 10
- App registers with cca_init

The last 3 steps being a race condition.  Sometimes the last two events
are reversed in order, and everything works fine.  (It's not just my
client BTW, the same happens with the example synth client at least)

So, what I'd like to know is:  does lash wait for cca_init to happen on
project restore after launching a client, or does it just launch it and
assume it can then start sending configuration values around?

Armed with that information, and maybe some helpful pointers to the
relevant areas of the code (if you can still pop that off the top of
your head) I'll see what I can do about fixing it.

Cheers,

-DR-