Re: Question about hdac_ext_link ref_count management

[Ranjani Sridharan <ranjani.sridharan@linux.intel.com>]

> > 
> > It looks like snd_hdac_ext_bus_link_power_up/down() are only called
> > during snd_hdac_ext_bus_link_get/put(). Actually, in my observation
> > disabling the CORB/RIRB buffer DMAs is what saves us power and this
> > is
> > done only if snd_hdac_ext_bus_link_put() is called on all links.
> > 
> > > The get() and put() are obviously for fully enabling and
> > > disabling
> > > the
> > > device, hence it's not suitable for the runtime PM
> > > suspend/resume.
> > > The power_up() / down() should be adjusted to fit with the
> > > runtime PM
> > > call, if any.
> > 
> > The only additional thing that snd_hdac_ext_bus_link_get/put() does
> > on
> > top of snd_hdac_ext_bus_link_power_up/down() is to stop the
> > CORB/RIRB
> > DMA when all the link ref_counts are 0. Do you think it is not
> > advisable to stop the CORB/RIRB DMA during runtime PM?
> 
> Why do you need to stop CORB/RIRB?  For stopping the CORB/RIRB DMA,
> you need to disable the IRQ and other stuff at first, in anyway.

I see. Let me go back and double check if powering down the link during
codec runtime suspend yields the same results in terms of power as well
and get back to you.

Thanks,
Ranjani