[alsa-devel] [PATCH 0/2] ASoC: tlv320dac33 fixes

Peter Ujfalusi peter.ujfalusi at nokia.com
Thu Mar 11 15:55:12 CET 2010

On Thursday 11 March 2010 16:46:28 ext Jarkko Nikula wrote:
> On Thu, 11 Mar 2010 16:26:20 +0200
> Peter Ujfalusi <peter.ujfalusi at nokia.com> wrote:
> > It has been found that OMAP3 McBSP needs the BCLK continuously running
> > on the serial interface when it is configured to be slave.
> Just curious: what would happen if the BCLK is cut while the McBSP is
> operating?

The symptom is that we can not access to McBSP register address space causing 
kernel panic, which can only be fixed by rebooting the device.
The burst driven BCLK causes some internal state machine to stuck, leaving the 
given McBSP port dead from the outside. Other ports operate after this event.
Obviously this only bites in McBSP slave mode, and with codec like DAC33 which 
have burst mode, in other cases the BCLK is always running (or McBSP is master).

> I'm thinking are there also other similar problems, e.g. if
> the rate is not correct.

Hmmm, could be possible, but I did not experienced with such a problem.


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