[alsa-devel] Intel HD: ALC662 noise-bug on FitPC2i

Bent Bisballe Nyeng deva at aasimon.org
Wed Dec 12 19:30:58 CET 2012

On 12/12/12 15:51, Takashi Iwai wrote:
> At Wed, 12 Dec 2012 15:45:46 +0100,
> Bent Bisballe Nyeng wrote:
>> On 12/12/12 15:25, Takashi Iwai wrote:
>>> At Wed, 12 Dec 2012 14:14:57 +0100,
>>> Bent Bisballe Nyeng wrote:
>>>> On 12/12/12 14:05, Clemens Ladisch wrote:
>>>>> Bent Bisballe Nyeng wrote:
>>>>>> When recording, audible clicking sounds are present in the resulting
>>>>>> audio data.
>>>>>> The corruption are composed of approximately 10 samples, and the
>>>>>> nature of the corrupted values are such that they could come from an
>>>>>> earlier buffer (the corrupted data resemble wav forms).
>>>>> This looks like a problem with your HDA controller; either the memory
>>>>> bus is overloaded so that some writes are dropped, or the hardware is
>>>>> just buggy.
>>>>> Regards,
>>>>> Clemens
>>>> I tried to record some audio using windows 7 and here the noise was not
>>>> present indicating that it is not buggy hardware.
>>>> Also, the system was not under load when the arecord call was made so if
>>>> the memory bus was overloaded I need another way to verify this.
>>>> Are there any additional (useful) debugging info I can subtract from the
>>>> system that will help aiding the debugging process?
>>> Which sound backend are you using at all?  Does the problem appear if
>>> you run with -Dhw for arecord?
>>> If it's using dsnoop or PulseAudio, the accuracy of DMA position
>>> reporting plays a big role.  In that case, changing position_fix
>>> option cures often.
>>> Takashi
>> There are no sound servers installed on the pc in question (it is a
>> 'lean' pc) so arecord should be using the hardware directly already.
> If you are using alsa-lib as is, it must be using dsnoop as default,
> which is pretty different from hw.
> Takashi

Running arecord with -Dhw did not solve the issue.

I played around with the buffer-size and have concluded that even with a
very large buffer the ticks are still present, precisely one tick per
buffer. This results in fever ticks with greater buffer sizes, but ticks

Are there any special kernel parameters that I should set in order to
make audio smooth?

I attached my kernel config just in case.

Kind regards
Bent Bisballe Nyeng

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