use those functions snd_pcm_hw_params_test_xxxxxx() 2009/9/8 Ng Oon-Ee <ngoonee@xxxxxxxxx> > Hello, please find below an issue I had with loading plugins into > pulseaudio. The pulse dev has sent this mail on his list concerning > alsa's interaction with pulse, indicating that there is something buggy > with how it works. Details below. I'd be willing to post something to > the bugtracker, if I only knew what the below means... > > -------- Forwarded Message -------- > From: Lennart Poettering <lennart@xxxxxxxxxxxxxx> > Reply-to: General PulseAudio Discussion > <pulseaudio-discuss@xxxxxxxxxxxxxxxx> > To: pulseaudio-discuss@xxxxxxxxxxxxxxxx > Subject: Re: [pulseaudio-discuss] Alsa output devices, able to use alsa > plugin? > Date: Fri, 4 Sep 2009 01:20:15 +0200 > > On Wed, 26.08.09 12:27, Tanu Kaskinen (tanuk@xxxxxx) wrote: > > > D: alsa-util.c: Trying test with SND_PCM_NO_AUTO_FORMAT ... > > D: alsa-util.c: Managed to open test > > D: alsa-util.c: Maximum hw buffer size is 371 ms > > I: alsa-util.c: snd_pcm_hw_params_set_periods_near() failed: Tiedostoa > tai hakemistoa ei ole > > I: alsa-util.c: snd_pcm_hw_params_set_buffer_size_near() failed: > Tiedostoa tai hakemistoa ei ole > > D: alsa-util.c: Trying test without SND_PCM_NO_AUTO_FORMAT ... > > D: alsa-util.c: Managed to open test > > D: alsa-util.c: Maximum hw buffer size is 371 ms > > I: alsa-util.c: snd_pcm_hw_params_set_periods_near() failed: Tiedostoa > tai hakemistoa ei ole > > I: alsa-util.c: snd_pcm_hw_params_set_buffer_size_near() failed: > Tiedostoa tai hakemistoa ei ole > > D: alsa-util.c: Trying plug:test with SND_PCM_NO_AUTO_FORMAT ... > > D: alsa-util.c: Managed to open plug:test > > D: alsa-util.c: Maximum hw buffer size is 371 ms > > I: alsa-util.c: snd_pcm_hw_params_set_periods_near() failed: Tiedostoa > tai hakemistoa ei ole > > I: alsa-util.c: snd_pcm_hw_params_set_buffer_size_near() failed: > Tiedostoa tai hakemistoa ei ole > > D: alsa-util.c: Trying plug:test without SND_PCM_NO_AUTO_FORMAT ... > > D: alsa-util.c: Managed to open plug:test > > D: alsa-util.c: Maximum hw buffer size is 371 ms > > I: alsa-util.c: snd_pcm_hw_params_set_periods_near() failed: Tiedostoa > tai hakemistoa ei ole > > I: alsa-util.c: snd_pcm_hw_params_set_buffer_size_near() failed: > Tiedostoa tai hakemistoa ei ole > > I: alsa-util.c: Failed to set hardware parameters on plug:test: Tiedostoa > tai hakemistoa ei ole > > E: module.c: Failed to load module "module-alsa-sink" (argument: > "device=test"): initialization failed. > > > > That "Tiedostoa tai hakemistoa ei ole" error means "No such file or > > directory". I tried also with device=hw:0,0 and device=plughw:0,0 and > > the first worked while the latter gave the same errors. Since the failed > > function calls pertain to buffering, I also tried with tsched=0. It > > worked. So, maybe this is a bug in the "plug" alsa plugin, ie. it > > doesn't implement the *_near() functions properly. > > > > Lennart, any insights? > > I am pretty sure that ALSA is broken here. We nowadays first try to > set the number of periods, and then set the buffer size in the > hwparams struct. If this fails we print a warning message (the ones > you see above with all the vowels regarding > snd_pcm_hw_params_set_periods_near() > resp. snd_pcm_hw_params_set_buffer_size_near()), but we do not > consider this fatal. > > After doing this we call snd_pcm_hw_params() to activate our > settings -- and if this fails then we consider this a fatal problem. > > Now the brokeness in ALSA is that after refusing our parameters it > still fails to configure our settings, i.e. calling the two functions > that fail breaks the hwparams setup: if we wouldn't call them, no breakage > happens at all. > > The two functions in question should either succeed or fail, but if > they fail they should not modify hwparams in a way that it > subsequently becomes unusable for snd_pcm_hw_params(). > > This issue needs to be fixed in ALSA. > > Lennart > > > _______________________________________________ > Alsa-devel mailing list > Alsa-devel@xxxxxxxxxxxxxxxx > http://mailman.alsa-project.org/mailman/listinfo/alsa-devel > _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
