[LAD] xrun callback
Hello, I'm trying to use jack_set_xrun_callback to be notified in my application of eventual xrun. in the documentation of the function I see a note: that 'this function cannot be called while the client is activated'. Does it mean that my client must call jack_set_xrun_callback before being activated or that the callback cannot be called while client is activated? If it's the later than should I use another client that will stay not activated as parameter jack_client_t It says return 0 on success. Does it mean the callback must succeed doing something or can it just increase some counter and return 0. What would be the consequences of a non-zero error code? Would jack stop? Currently I'm registering the callback and then activate and use the client. I'm not sure if I get an xrun that does crash my application of if something wrong in the application makes it crash and trigger an xrun... Chicken and egg problem. Is there another way? Thanks -- Raphaël. for reference: from jack.h /** * Tell the JACK server to call @a xrun_callback whenever there is a * xrun, passing @a arg as a parameter. * * All "notification events" are received in a seperated non RT thread, * the code in the supplied function does not need to be * suitable for real-time execution. * * NOTE: this function cannot be called while the client is activated * (after jack_activate has been called.) * * @return 0 on success, otherwise a non-zero error code */ int jack_set_xrun_callback (jack_client_t *client, JackXRunCallback xrun_callback, void *arg) JACK_OPTIONAL_WEAK_EXPORT; ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
[LAD] xrun callback
On 09/03/2014 04:04 PM, Raphaël BOLLEN wrote: Hello, I'm trying to use jack_set_xrun_callback to be notified in my application of eventual xrun. in the documentation of the function I see a note: that 'this function cannot be called while the client is activated'. Does it mean that my client must call jack_set_xrun_callback before being activated Yes. First set the callback, and only later call jack_activate(). Two tiny jack clients which may come in handy: * jackxrun: report x-runs on the command line * busyjack: create artificial load http://gareus.org/gitweb/?p=jackfreqd.git;a=tree;f=tools; gcc -o jackxrun jackxrun.c -ljack gcc -o busyjack busyjack.c -ljack ./jackxrun # reports xruns in the terminal ./busyjack 90 # will ramp things up to 90% DSP load (default is 50) It can be used to create x-runs, yet it's not the same as a x-run from hw. [..] It says return 0 on success. Does it mean the callback must succeed. Your callback function must return 0. Cheers! robin Thanks Robin for your explanations and tools. I think the x-runs (one every few hours) I get are due to hardware because jack_cpu_load is < 5% and system load average < 0.2 all periods. The problem is that those xruns make the process thread jump to 100% cpu and the process disappears from QJackctl, although jack and other clients still run normally. The code also runs fine on another computer. I'm currently testing with jack priority raised from 40 to 70 to be above irq threads. I did not yet have an xrun in this config but It's a bit early to conclude. I will also try busyjack. Best regards -- Raphaël. ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
Re: [LAD] xrun callback
On 09/03/2014 04:04 PM, Raphaël BOLLEN wrote: > Hello, > > I'm trying to use jack_set_xrun_callback to be notified in my > application of eventual xrun. > > in the documentation of the function I see a note: that 'this function > cannot be called while the client is activated'. > > Does it mean that my client must call jack_set_xrun_callback before > being activated Yes. First set the callback, and only later call jack_activate(). Two tiny jack clients which may come in handy: * jackxrun: report x-runs on the command line * busyjack: create artificial load http://gareus.org/gitweb/?p=jackfreqd.git;a=tree;f=tools; gcc -o jackxrun jackxrun.c -ljack gcc -o busyjack busyjack.c -ljack ./jackxrun # reports xruns in the terminal ./busyjack 90 # will ramp things up to 90% DSP load (default is 50) It can be used to create x-runs, yet it's not the same as a x-run from hw. [..] > It says return 0 on success. Does it mean the callback must succeed. Your callback function must return 0. Cheers! robin ___ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev
