[alsa-devel] Fwd: ALSA queries

[Takashi Iwai]

On Tue, 07 Aug 2018 14:08:05 +0200,
Chakravarthi Pradeep wrote:
> 
> Dear Takashi,
> 
> In previous mail you have mentioned
> > So, either the measurement is wrong, or the stream is already screwed
> > up at the time you call snd_pcm_period_elapsed().
> 
> what it means "measurement is wrong"  and how to make that measurement
> is correct ?

See what I wrote: "either".  I can't exclude the possibility that you
are measuring the code calls incorrectly, of course.  This is one
case.  Another case would be the incorrect state that is already
screwed up at the time of snd_pcm_period_elapsed() call.


Takashi


> Regards,
> Chakravarthi
> On Tue, Aug 7, 2018 at 5:33 PM Takashi Iwai <tiwai at suse.de> wrote:
> >
> > On Tue, 07 Aug 2018 13:59:46 +0200,
> > Chakravarthi Pradeep wrote:
> > >
> > > Dear Takashi,
> > >
> > > Trigger stop is getting called , because of this hwptr is zero and
> > > pointer call back is not getting called. Below is my log from driver.
> > >
> > > [  838.491681] Trigger:Start
> > > [  839.522233] hwptr=0 buf_pos:3456
> > > [  839.522244] buf_pos :3456 bytes_to_frames:864 uhdc_audio_pcm_pointer_253
> > > [  839.522249] Trigger:Stop
> >
> > Then you need to figure out the code path of the trigger stop.
> >
> > > In normal scenario, Trigger stop is not getting called and audio was
> > > able to render in the VLC application. Below log for normal scenario,
> > > [  802.785893] Trigger:Start
> > > [  814.288309] hwptr=0 buf_pos:6272
> > > [  814.288323] buf_pos :6272 bytes_to_frames:1568 uhdc_audio_pcm_pointer_253
> > > [  814.288362] buf_pos :6272 bytes_to_frames:1568 uhdc_audio_pcm_pointer_253
> > > [  814.288378] buf_pos :6272 bytes_to_frames:1568 uhdc_audio_pcm_pointer_253
> > > [  814.305079] hwptr=6272 buf_pos:9472
> > > [  814.305091] buf_pos :9472 bytes_to_frames:2368 uhdc_audio_pcm_pointer_253
> > > [  814.321741] hwptr=9472 buf_pos:12672
> > > [  814.321748] buf_pos :12672 bytes_to_frames:3168 uhdc_audio_pcm_pointer_253
> > > [  814.321777] buf_pos :12672 bytes_to_frames:3168 uhdc_audio_pcm_pointer_253
> > > [  814.321785] buf_pos :12672 bytes_to_frames:3168 uhdc_audio_pcm_pointer_253
> > > [  814.338452] hwptr=12672 buf_pos:15872
> > > [  814.338459] buf_pos :15872 bytes_to_frames:3968 uhdc_audio_pcm_pointer_253
> > > [  814.355242] hwptr=15872 buf_pos:19072
> > > [  814.355248] buf_pos :19072 bytes_to_frames:4768 uhdc_audio_pcm_pointer_253
> > > [  814.355288] buf_pos :19072 bytes_to_frames:4768 uhdc_audio_pcm_pointer_253
> > > [  814.355294] buf_pos :19072 bytes_to_frames:4768 uhdc_audio_pcm_pointer_253
> > > [  814.371822] hwptr=19072 buf_pos:22272
> > > ...
> > > ...
> > > [  830.739031] Trigger:Stop
> > >
> > >
> > > I can not do rmmod for ALSA driver. If I do sudo rmmod mydriver then it says
> > > "rmmod: ERROR: Module mydriver is in use"
> > >
> > > How can I remove mydriver module from linux kernel ?
> >
> > Likely some program is using the sound device.  For example, a mixer
> > applet or PulseAudio keeps opening the control device.
> > Check it via "fuser -v /dev/snd/*"
> >
> >
> > Takashi
> 
> 
> 
> -- 
> Thanks and Regards
> Chakravarthi Pradeep.K
> Ph: 91 9980434900
>