[maemo-developers] Frequencies scaling with OS2008

Tue Jan 1 21:12:02 EET 2008

Simon Pickering wrote:

> It would be interesting to see whether the mp3 task (for example) can  
> decode in real time when the DSP is run at 133MHz or are your  
> audio/video sync problems because it's running too slowly? This would  
> remove some load from the CPU and allow us to use the DSP for something.

As I mentioned in some previous mail, it is quite easy, just redefine 
O_DSP_H on line 44 of arch/arm/mach-omap2/board-n800-dvfs.c
Here is testing kernel with this state defined as 400/133.
http://fanoush.wz.cz/maemo/zImage-2.6.21.0-osso63-dsp133.tar.gz

Tried few mp3 songs and radios and didn't hear any problems, 128kbps is 
absoulutely fine and I didn't notice any problem also with VBR with 
average rate ~160kbps (some frames even 224 or 320 kbps). I don't have 
any music in AAC or very high constant mp3 bitrate.

Frantisek