[LAD] Can someone add 2 features to Kluppe?

Patrick Shirkey pshirkey at boosthardware.com
Tue Jul 20 07:17:01 UTC 2010


On 07/20/2010 09:45 AM, Robin Gareus wrote:
> On 07/20/2010 01:06 AM, Louigi Verona wrote:
>    
>>
>> Hey guys!
>>
>> Some time ago I have asked someone to look into Kluppe and add a couple of
>> features.
>> My request was not ignored and Patrick Shirkey was kind enough to volunteer
>> to try to help.
>>
>> However, he came upon a difficulty and that is - *how do you set up an
>> asynchronous timer in C?*
>>      
> It depends what you need that timer for.
>
>    

The timer is needed to countdown the period between stopping and 
restarting the loop. The methods I have tried all halt the playback on a 
single frame and the ui also becomes unresponsive while the timer is in 
process.

All I would like to do is pass a zero byte to the audio signal handling 
code while the timer is in progress. The rest of the interface should 
stay active.

> In gtk there's a g_timeout_add(). easy to use.
>    

Will check that one. Might do the trick.

> To writing your own:
> `apropos pthread` and more specifically `man pthread_create`.
>
>    

Otherwise will look into this.

> usleep() sleeps at least, and select() sleeps at most a certain period
> of time. http://freej.dyne.org/codedoc/fps_8cpp_source.html line 132ff
> has examples of both.
>    

Tried both of these options and they cause the app to pause with an 
annoying buzz while the timer is in effect.

> For [more] accurate timing: RTC or HPET. Example code comes
> with the kernel:
>   linux-2.6/Documentation/rtc.txt
>   linux-2.6/Documentation/hpet.txt
>
> There's a couple of other options fi. if you want to sync
> hardware-devices using IRQs.. and the jack_process_callback is also very
> good timer :)
>
>    

Not required for this task.



>> It stopped right there. I was wondering if anyone could help us with that
>> matter?
>>
>>
>> Cheers!
>>
>>      
>
>    


-- 
Patrick Shirkey
Boost Hardware Ltd




More information about the Linux-audio-dev mailing list