Re: [Jack-Devel] Patches for jack-0.121-3

On Thu, Mar 22, 2012 at 10:55:18AM +0100, Stéphane Letz wrote:
 
 
> Right now I see two flags that force "re-init" of the DLL: engine->first_wakeup  and timer->reset_pending. Those flags are tested in jack_run_cycle (engine->first_wakeup || timer->reset_pending).
> 
> 1) "first_wakeup" is set in jack_engine_new and in jack_stop_freewheeling. 
> 
> 2) "reset_pending" is set in jack_engine_delay
> 
> Would it make sense to keep only one flag? and set it in 4 places: first cycle, stop freewheel, XRun handling, buffer size change?

I didn't remove 'reset_pending' because I wasn't sure if 
'first_wakeup' could be used from the context that sets
'reset_pending'. The 'pending' part suggested something
asynchronous, i.e. this flag implicitly being used as a
sema in combination with some mutexes.

Apart from that there could be just one flag.

But you really want the 'perfect' way, there could be more.
There are 3 things to initialise:

1. next_wakeup (to the current wakeup time, as the DLL will run)
2. period_usecs
3. filter_omega

'First cycle' and 'buffer size change' should set them all.
For 'xrun' and 'end of freewheeling', just setting (1) is
enough, as the current value of (2) would be more accurate
than the initial one, and (3) is a constant.

There are two other matters to consider/check.

For the first, see the comments near the end of jack_run_cycle();

The second concerns Jack1 only IIRC. If a cycle is skipped, 
the DLL should be run anyway. Jack1-0.121.3 did the right
thing and I don't think the patches affect this. But it's
worth checking.

Ciao.

-- 
FA

A world of exhaustive, reliable metadata would be an utopia.
It's also a pipe-dream, founded on self-delusion, nerd hubris
and hysterically inflated market opportunities. (Cory Doctorow)

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