[alsa-devel] ASoC related suspend problems on OMAP3

Grazvydas Ignotas notasas at gmail.com
Thu Feb 9 14:41:03 CET 2012

On Thu, Feb 9, 2012 at 10:59 AM, Peter Ujfalusi <peter.ujfalusi at ti.com> wrote:
> On 02/08/2012 06:19 PM, Grazvydas Ignotas wrote:
>> ok I've figured it out myself - it's because of McBSP2 clock source
>> selection. Pandora has rather unusual config (compared to other
>> boards) that it gets McBSP2 audio clock through external pin. As long
>> as it's set to PRCM functional clock (OMAP internal, reset default)
>> the system suspends fine, but if it's set to external,
>> per_pwrdm+core_pwrdm won't switch to lower power states.
>> Pandora sets this by calling snd_soc_dai_set_sysclk() from
>> snd_soc_ops.hw_params callback. Now I wonder, where should I set the
>> clock back so it suspends again, perhaps from snd_soc_ops.hw_free
>> callback? Or maybe it should be handled by omap-mcbsp ASoC driver,
>> perhaps something needs to be configured on McBSP itself for it to go
>> idle with external clock set?
> I assume this worked in the past on pandora (suspend), right?

Not really, we did not have working suspend until now due to unrelated
driver issues (we are slow, I know..).

> Can you try one _hack_ to see if it helps?
> In omap_mcbsp_request function:
> set the CLOCKACTIVITY field to 0x3 in the sysconfig register.
> Or you can as well try to do the same in
> mach-omap2/omap_hwmod_3xxx_data.c, look for omap3xxx_mcbsp_sysc, and
> change the .clockact = 0x2 to 0x3.
> Not sure if this helps, but I would be interested to see the results...

I've changed the hwmod data and it doesn't seem to help. After
playing, just before suspend, I've tried to read mcbsp2 SYSCONFIG
through /dev/mem and it seems CLOCKACTIVITY is 0 at that time. Also
tried forcing CLOCKACTIVITY to 3, 2, 1 using the same method just
before suspend, didn't help either. As soon as I cleared MCBSP2_CLKS
in CONTROL_DEVCONF0 it started suspending properly.


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