[ARMedslack] Improving USB audio sound quality on the Dockstar

[Andrzej Telszewski]

On 05/05/2011 10:32 AM, Thorsten Mühlfelder wrote:
> Hi,
> 
> I'm using a high quality USB audio device (Burr-Brown Japan PCM2702) with my 
> Dockstar. I've configured mpd to use the hardware interface without dmix 
> because dmix seems to be broken on the ARM platform.
> 
> But there is one problem left: sometimes clicks and pops can be heard. They 
> appear randomly up to 2 times a minute. My impression is that hard disk data 
> transfer causes them, because using "hdparm -t" makes the situation worse. On 
> the Dockstar all USB devices are connected via hub to the same USB 
> controller:
> # lsusb
> Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
> Bus 001 Device 002: ID 05e3:0608 Genesys Logic, Inc. USB-2.0 4-Port HUB
> Bus 001 Device 003: ID 0bc2:2120 Seagate RSS LLC 
> Bus 001 Device 005: ID 08bb:2702 Texas Instruments Japan Speakers
> 
> Is it possible to give the USB audio data transfers a higher priority?
> 

Hi,

You might try 'chrt', but you need to find the process(es) ID(s)
responsible for all the audio stuff. Eventually, check here:

http://subversion.ffado.org/wiki/IrqPriorities

but it's rather about real-time Linux.

-- 
Pozdrawiam,
Best regards,
Andrzej Telszewski