[TouchPad General] benfikaman:
we have all seen the sound issue with cm7/cm9 where the sound is distorted upon screen shutting down.

I thought maybe getting our research together may be able to help someone develop a fix so i'll start.

Based on some tear down research, I figured out the the touchpad comes with the Wolfson WM8958

here is a pdf with great info and diagrams (including pin layouts and diagrams, max ratings, and recommend operating conditions):

http://www.wolfsonmicro.com/documents/uploads/product_briefs/en/WM8958_ProductBrief_1.pdf

link: http://www.wolfsonmicro.com/products/audio_hubs/WM8958/

key features:

Features

24-bit 4-channel Hi-Fi DAC and 2-channel Hi-Fi ADC

100dB SNR during DAC playback (‘A’ weighted)

Smart MIC interface

- Power, clocking and data input for up to four digital MICs

- High performance analogue MIC interface

- MIC activity detect & interrupt allows processor to sleep

2W stereo (2x2W) class D/AB speaker driver

Capless Class W headphone drivers

- Integrated charge pump

- 5.3mW total power for DAC playback to headphones

4 Line outputs (single-ended or differential)

BTL Earpiece driver

Digital audio interfaces for multi-processor architecture

- Asynchronous stereo duplex sample rate conversion

- Powerful mixing and digital loopback functions

ReTune™ Mobile 5-band, 6-channel parametric EQ

Multiband compressor and dynamic range controller

Dual FLL provides all necessary clocks

- Self-clocking modes allow processor to sleep

- All standard sample rates from 8kHz to 96kHz

Active noise reduction circuits

- DC offset correction removes pops and clicks

- Ground loop noise cancellation

Integrated LDO regulators

72-ball W-CSP package (4.516 x 4.258 x 0.7mm)

----------------------------------------------------

now they have an opensource that may or may not be helpful:

http://opensource.wolfsonmicro.com/

Linux 2.6.38 was just released. As ever this release incorporates many enhancements from Wolfson, including substantial improvements in the memory usage when used with large and flexible devices such as modern audio hub CODECs and new driver support for WM8326, WM8737, WM8770 and WM8958

http://opensource.wolfsonmicro.com/content/wolfson-updates-2638

i was reading some information posted by timepants and eventually used by biotech creator of Touchvol on the webos side that seems interesting and may be useful:

here is a copy and paste since i'm not sure if i can post the link to another forum here.

To modify some "hidden" WM8958 CODEC settings from the console you can use the below commands using novaterm. I should caution that you should be very careful because you can break something if you set your headphones or the internal speakers to drive beyond their normal operating limits.

A reboot should reset the values to default.

See what mixer channels are available: "amixer" <enter>. I recommend copying the contents to a text editor window so you can maintain a list of defaults (which are the bottom line of each printed section). The headphones are tied to items relating to "AIF1" and "AIF1DAC1". I haven't explored speakers yet.

To control volume: amixer set "Headphone" <0..63>

To control volume boost: amixer set "AIF1 Boost" <0..3>

To enable/disable "3D Stereo": amixer set "3D Stereo" toggle

There are settings for an EQ but I haven't had success getting it to work yet. The associated settings appear to be "AIF1DAC1 EQ", "AIF1DAC1 EQ1", "AIF1DAC1 EQ2", "AIF1DAC1 EQ3", "AIF1DAC1 EQ4", "AIF1DAC1 EQ5", "AIF1DAC1 Enhanced EQ". Maybe there's another toggle or channel selection involved?

If anyone discovers any additional useful settings, be sure to share.

Edit: Changed WM8994 to WM8958. The kernel module in use is the WM8994 which is what confused me originally.

also seems like from reading the software may not take full advantage of the hardware, it may be using 2x1w rather then the 2x2w.

hope some of this helps, maybe we can get this issue resolved, thanks for reading