[alsa-devel] twl4030 latency update

[Peter Ujfalusi]

On 03/26/2014 11:35 AM, Leonardo Gabrielli wrote:
> 
> On 26/03/2014 09:26, Peter Ujfalusi wrote:
>> Can you elaborate on the corrupted/scrambled audio? I just don't see how it
>> can happen. Can you get the /proc/asound/card0/pcm0p/sub0/hw_params when you
>> have the audio quality issue?
> Hello,
> Here you are:
> 
> cat /proc/asound/card0/pcm0p/sub0/hw_params
> access: MMAP_INTERLEAVED
> format: S16_LE
> subformat: STD
> channels: 2
> rate: 22050 (22050/1)
> period_size: 512
> buffer_size: 1024
> 
> And this is jack output:
> 
> jackd -P62 -t2000 -dalsa -dhw:0 -r22050 -p512 -n2 -s -S -i2 -o2 &

arecord -r 22050 -f S16_LE --period-size=512 --buffer-size=1024 -v | aplay -r
22050 -f S16_LE  --period-size=512 --buffer-size=1024 -v

and no issue on the headphone from Beagle.

> I can send you saomething to get it clearer. I recorded  a 10Hz sine wave with
> jaaa. The wave is totally scrambled (probably buffers are not read in order).
> But it may well be an issue with jack.
> 
> When the output sounds correct (256 period) hw_param is:
> cat /proc/asound/card0/pcm0p/sub0/hw_params
> access: MMAP_INTERLEAVED
> format: S16_LE
> subformat: STD
> channels: 2
> rate: 22050 (22050/1)
> period_size: 256
> buffer_size: 768

arecord -r 22050 -f S16_LE -v --period-size=256 --buffer-size=768 | aplay -r
22050 -f S16_LE  --period-size=256 --buffer-size=768 -v

again, audio is clear with this one as well

>> I can not run jackd on the board anymore (with linux-next at least):
>> FATAL: cannot locate cpu MHz in /proc/cpuinfo
> 
> Yes, there's been a recent fix to that (you can checkout the latest jackd from
> git repos, see this thread:
> http://lists.jackaudio.org/private.cgi/jack-devel-jackaudio.org/2014-March/012167.html

I also found this, but lazy to update my jack...

> Or maybe you can just start jackd specifying a different clock with the -c
> switch i.e.
> jackd -P62 -t2000 -c s -dalsa -dhw:0 -r22050 -p512 -n2 -s -S -i2 -o2 &

This does not work.

-- 
Péter