[Sound-open-firmware] how to find a suitable value for the TFT/RFT parameter on multi-platform

[zhigangw]

Hello Liam:

         I think it is better to mention this status again in the mail list.

I am working on playback with the TDM8(4slot used)-48KHz-32bit on 
APL-GPMRB platform.

Currently the status is:

The music can be heard from the all four channels.

But the it has the noise on the background. the noise exists all the 
time during playing.

No xrun happened during the audio playing.

I have not tried the pause/resume feature.

I have not tried keyon's patch for the noise issue.


Issue:

During the development, the TFT (in SSP's SSC3 register) parameter will 
affect the playing operation.

If we keep code: tft = active_tx_slots * 4;  the tft will be 16.

during the playing, i found the DMA IRQ will happened very frequently, 
less than 1ms,

which will cause XRUN during playing. But it will be normal if the tft 
value is below 8 (tft < 8).


I did some tests on other platform. but I have not found suitable way to 
fit all of them.

the RFT also have the similar concern.


Do you have any suggestions about this?


thank you

br

~zhigang