Hi Takashi, How to enable log from ALSA lib core or ALSA core , so that I will come to know why trigger stop call back is getting called back by itself. ring bufffer size is 57600 and minimum bytes device generates per period is 3200(bytes). I have read one frame is 4 bytes from below link. https://www.alsa-project.org/main/index.php/FramesPeriods So is it correct to give below values to snd_pcm_hardware .period_bytes_min = 3200 /* per interrupt device provides minimum 3200 bytes of data*/ .periods_min = 72 /* 3200/4 /* 4 is because of (2 (channel )* (16 bits/2)) */ Regards, Chakravarthi On Tue, Aug 7, 2018 at 7:13 PM Takashi Iwai <tiwai@xxxxxxx> wrote: > > On Tue, 07 Aug 2018 15:36:22 +0200, > Chakravarthi Pradeep wrote: > > > > >In the case above it's in frames. But it can be defined in bytes > > >depending on the hardware spec. Some hardware defines in the time > > >unit (like msec), too. > > > > Can you please tell me how to define in bytes ? > > Read the source before asking like this. If not found, read the > source again. If still it's not fulfilled, ask more specific > questions. > > The driver doesn't define it. Rather the driver lets ALSA PCM core > choose the parameters given from user-space. But some parameters > might not fit with the requirement of your hardware. For satisfying > it, the driver may give hw constraints to PCM core beforehand, > typically set in the open callback. > > > >Now you know it. And remember that PA is often die-hard. > > So it means that I can not do rmmod until pulseaudio is removed , is > > it correct ? > > Yes. You cannot rmmod during any program is accessing to the sound > device, not only PA. > > > Takashi > > > Regards, > > Chakravarthi > > On Tue, Aug 7, 2018 at 6:45 PM Takashi Iwai <tiwai@xxxxxxx> wrote: > > > > > > On Tue, 07 Aug 2018 15:12:08 +0200, > > > Chakravarthi Pradeep wrote: > > > > > > > > Dear Takashi, > > > > > > > > Thanks for your reply. > > > > > > > > > The "period" in ALSA PCM definition represents the interval time (or > > > > > frames) of the periodical interrupts on the ring buffer. If the irq > > > > > is issued for each 256 frames while the ring buffer size is 1024 > > > > > frames, periods = 1024/256 = 4. The periods_min defines the minimal > > > > > number of periods the hardware may accept. > > > > > > > > Is it 256 frames or 256 bytes ? > > > > > > In the case above it's in frames. But it can be defined in bytes > > > depending on the hardware spec. Some hardware defines in the time > > > unit (like msec), too. > > > > > > > fuser -v /dev/snd/* output is > > > > USER > > > > PID ACCESS COMMAND > > > > /dev/snd/controlC0 Dell 1815 > > > > F..... pulseaudio > > > > > > Now you know it. And remember that PA is often die-hard. > > > > > > > > > Takashi > > > > > > > > -- > > Thanks and Regards > > Chakravarthi Pradeep.K > > Ph: 91 9980434900 > > -- Thanks and Regards Chakravarthi Pradeep.K Ph: 91 9980434900 _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
