2010/9/8 IOhannes m zmoelnig <zmoelnig@xxxxxx> > On 2010-09-07 19:06, Clemens Ladisch wrote: > > IOhannes m zmoelnig wrote: > >> i'm requesting my "plughw" device with 44100Hz > >> the request is done with something like: > >> rate=44100; > >> err = snd_pcm_hw_params_set_rate_min(handle, params, &rate, 0); > > > > This requests a sample rate of at least 44100 Hz. > > yes. this is good enough for me. > (it shouldn't crash though) > > http://www.alsa-project.org/alsa-doc/alsa-lib/group___p_c_m___h_w___params.htm Restrict a configuration space with a minimum rate. val approximate minimum rate ( on return filled with actul minimum ) dir sub unit direction (on return filled with actual direction) Return 0 otherwise a negative error code if configuration space would become empty what is the minimum rate returned by snd_pcm_hw_params_get_rate_min() when using hw:0,0 ? > > >> [...] > >> err = snd_pcm_hw_params(handle, params); > >> > >> what happens: > >> in the snd_pcm_hw_params(), my program exits with: > >> "interval_inline.h:52: snd_interval_single: Assertion > >> `!snd_interval_empty(i)' failed." > > > > You called snd_pcm_hw_params with an invalid params structure. > > I'd guess that snd_pcm_hw_params_set_rate_min (or some other > > snd_pcm_hw_params_set_*) returned an error. > > i wish you were right. > however, it seems like i am blindfolded. > > i noticed however, that i need to set both the rate (i use > snd_pcm_hw_params_set_rate_min()) and the period size (i use > snd_pcm_hw_params_set_period_size_near()), in order to make it crash. > > attached is an example code that triggers the crash. > please someone shed some light... > > gmasdr > IOhannes > > > PS: that's how i use the sample program: > $ gcc -o alsatest alsatest.c $(pkg-config --cflags --libs alsa) > $ ./alsatest > trying to open 'hw:0' as CAPTURE > configuring device succeeded > CAPTURE configured > trying to open 'hw:0' as PLAYBACK > configuring device succeeded > PLAYBACK configured > trying to open 'plughw:0' as CAPTURE > configuring device succeeded > CAPTURE configured > trying to open 'plughw:0' as PLAYBACK > alsatest: interval_inline.h:55: snd_interval_single: Assertion > `!snd_interval_empty(i)' failed. > Aborted > > so it seems to work fine with "hw:0" but not with "plughw:0". > > you can specify the device to be opened on the cmdline: > $ ./alsatest hw:2 > > To debug , you will need to enable RULES_DEBUG In pcm_params.c add snd_pcm_dump() after snd_pcm_hw_params in your program export LIBASOUND_DEBUG=1 and post the output of your program _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
