Re: [Jackit-devel] Re: Real-Time Preemption, -RT-2.6.10-rc2-mm3-V0.7.31-19

["Jack O'Quin" <joq@io.com>]

Florian Schmidt <mista.tapas@gmx.net> writes:

> I suppose instead of catching the signal the user might just monitor the
> syslog. I'm not sure there's printk's triggered by thisalready , but i'm
> sure if not, ingo might add them. So a trivial patch for jackd would
> probably look like this:
> 
> --- libjack/client.c.orig       2004-12-02 17:55:04.000000000 +0100
> +++ libjack/client.c    2004-12-02 17:56:23.000000000 +0100
> @@ -1238,6 +1238,9 @@
>                         if (control->sync_cb)
>                                 jack_call_sync_client (client);
>  
> +                       // enable atomicity check for RP kernels
> +                       gettimeofday(1,1);
> +
>                         if (control->process) {
>                                 if (control->process (control->nframes,
>                                                       control->process_arg)
> @@ -1247,7 +1250,10 @@
>                         } else {
>                                 control->state = Finished;
>                         }
> -
> +
> +                       // disable atomicity check
> +                       gettimeofday(0,1);
> +
>                         if (control->timebase_cb)
>                                 jack_call_timebase_master (client);
>  

The sync_cb and timebase_cb callbacks actually need to be RT-safe,
too.  ;-)

Is printk() guaranteed not to wait inside the kernel?  I am not
familiar with its internal implementation.
-- 
  joq