2009/8/3 javier Martin javier.martin@vista-silicon.com:

As I described in one of my previous mails, I have been trying to port an old ASoC driver for kernel 2.6.22 to latest stable 2.6.30 kernel. I am currently facing a big problem which make some repeated samples appear with a regular pattern:

• frequency of bad samples = 2 * period_size
• bad samples in audio stream are taken from "buffer_size" samples

back in the original file.

You can reproduce this with: aplay -t raw -f S16_LE -r8000 8k16bitpcm.wav

(http://en.wikipedia.org/wiki/WAV to get this file)

Here I submit two patches:

• One which adds ssi and dma drivers plus a custom machine driver

(imx27asoc_list.patch).

• Another patch which adds wm8974 codec support taken from ASoC

wm8974-upstream branch (wm8974_list.patch).

Note that the machine driver attached uses wm8974 codec, thus second patch is needed. Please, note also that patches are currently quite dirty, and in an early development state. The purpose of this mail is not to even consider to include them in any branch right now, but to gather some help to solve the problem. As soon as I have it solved I will clean all the stuff and try to prepare it for mainline.

-- Javier Martin Vista Silicon S.L. Universidad de Cantabria CDTUC - FASE C - Oficina S-345 Avda de los Castros s/n 39005- Santander. Cantabria. Spain +34 942 25 32 60 www.vista-silicon.com

I was doing some random tests and I have found that using "-M" option in aplay makes it work fine. It seems a problem of performance when not using mmap.

I don't know if you have something to comment about this.

Thanks.