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Noise in audio playback on OMAP3, TPS65930 codec using ALSA driver (Linux kernel 2.6.22.18)

Ruchi
Prodigy 50 points

Other Parts Discussed in Thread: TPS65930

Hi,

I am working on the Linux sound driver (with kernel 2.6.22.18) for OMAP3 based custom board and TPS65930 codec. 

I have detected noise in stereo playback when audio was played using aplay with the ALSA sound driver. Mono playback worked fine without any noise.

I have also tested playing audio on 2.6.29 kernel with ALSA drivers, no noise was detected in this case. Since 2.6.29 kernel worked without any issues I modified the audio register settings on 2.6.22.18 kernel to match with that of kernel 2.6.29. This was not fruitful in removing the noise issue with playback on 2.6.22.18 kernel.

I came across the same problem in another thread in this forum. The link to this thread is given below for your reference:

http://e2e.ti.com/forums/t/6869.aspx

A verified answer by Kevin Guo suggests that upgrading the PSP to a latest version will fix the noise issue. This is applicable only to kernel 2.6.29. Our product development is based on kernel 2.6.22.18 and we cannot upgrade to kernel 2.6.29 at this stage.

 

What could be the reason for the noise? How can we fix this issue on kernel 2.6.22.18?

 

Thanks in advance,

Ruchi Sirauthiya.

  • 0
    TI__Prodigy 200 points

    I work on the TPS65930 hardware, so I may not be the right person to support this issue. One suggestion : Please ensure that the register programming sequence is the same in both the driver versions. The sequencing can have an impact on the audio quality.