Hannu Savolainen wrote:
> Stéphane Letz wrote:
>> Ok. Now testing with O_EXCL and SNDCTL_DSP_COOKEDMODE works, bit I see  
>> some strange of the device. The overruns/underrun detection code based  
>> on SNDCTL_DSP_GETERROR does not see underrun anymore although the  
>> sound get weird with high CPU load (Writing another buffer in the out  
>> device solve the "weird sound" problem...). The same overruns/underrun  
>> detection code was working when opening the /dev/dsp0 device (that  
>> uses vmix AFAIK)
>>
>> This occurs on OpenSolaris with internal HDAudio using published OSS  
>> 4.0. Are tey know problems with this card with OSS 4.0 ?
>>   
> I don't think this is caused by problems with any particular card. 
> Underruns/overruns will happen if the CPU load gets too high (more than 
> 80-90%). In this situation the application is not able to process audio 
> data as fast as it should. It's often possible to decrease the problem 
> by using higher priority (see man sched_setscheduler).
> 
> It is just necessary to write enough silent data to the output device 
> before starting the read/write loop. It is normal that the other 
> processes running in the computer occasionally delay the audio process 
> by few milliseconds. If there is not enough data in the playback buffer 
> then this delay will cause an underrun. In addition recorded data will 
> get accumulated in the recording device during the delay. This will 
> sooner or later cause recording overruns if the application doesn't 
> handle this properly. Simple read/write loop (without any 
> usleep/whatever calls) will recover from this situation automatically.
> 
> Best regards,
> 
> Hannu
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> oss-devel@mailman.opensound.com
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> 

Hi,

Have you tried to use the fulldup.c test program to see if this works
http://mercurial.opensound.com/?file/2fed97c765ec/tutorials/sndkit/samples/fulldup.c


If fulldup.c shows problems then there are issues with vmix.

Have you tried disabling vmix to see if the native device behaves 
differently than the vmix device?


regards
Dev Mazumdar

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