noise issues when recording sound on i.MX28

[u.kleine-koenig@pengutronix.de (Uwe Kleine-König)]

Hello Fabio,

On Tue, Feb 16, 2016 at 01:01:19PM -0200, Fabio Estevam wrote:
> On Thu, Feb 11, 2016 at 6:40 AM, Uwe Kleine-K?nig
> <u.kleine-koenig@pengutronix.de> wrote:
> 
> > root at hostname:/sys/kernel/debug/clk find -name saif?_sel
> > ./ref_xtal/pll0/saif0_sel
> > ./ref_xtal/pll0/saif1_sel
> >
> > root at hostname:/sys/kernel/debug/clk cat ./ref_xtal/pll0/saif?_sel/clk_rate
> > 480000000
> > 480000000
> 
> Ok, what about the SAIF0 and SAIF1 sampling rates: are they always the same?

Lothar found a recipe to reproduce. I didn't try, but it's something
along the lines of (Lothar please correct if I'm wrong):

 - start a recording on one SAIF
 - start playback on the other SAIF
 - using direct access to the registers stop and restart the playback
   SAIF via the RUN bit.

The program I have doesn't provide a reliable reproduction recipe, it
runs in a loop and sometimes need several (>1000) iterations to trigger.
In my setup the sampling rates don't change. The values of
BITCLK_MULT_RATE differ however in my setup, I don't see why though.

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-K?nig            |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |