[alsa-devel] [RFC PATCH] ALSA: hda - add support for runtime power management

Lin, Mengdong mengdong.lin at intel.com
Sun Aug 19 12:46:42 CEST 2012

> Looking at your original patch, just a few points I'd like to clarify:
> - Don't use snd_printd().  It's a debug print most of distros turn
>   ON, thus it'd be annoying.  If any, use snd_printdd().

Okay. I'll remove snd_printd(). Thanks for pointing out this.

> - The IRQ reassignment is required for runtime PM?

I'm not sure if the IRQ reassignment can be removed and I'll double check this. 
> - Why you call snd_pcm_suspend_all() in azx_runtime_suspend()?
>   In which situation would a PCM stream be pending?

snd_pcm_suspend_all() should not be called in azx_runtime_suspend(), since there is no active PCM streams when ready for runtime suspend. I'll remove it. 

> - Are snd_power_change_state() calls needed for runtime PM?
I think this is needed. It's because HW is actually in D3 when it's runtime suspended and need a delay for transition back to D0. And there are operations that need HW in D0, such as snd_pcm_prepare().

Thanks again!

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