[alsa-devel] [PATCH] ALSA: hda - Fix runtime PM accounting

[Takashi Iwai]

At Fri, 31 Aug 2012 01:57:09 +0000,
Lin, Mengdong wrote:
> 
> > -----Original Message-----
> > From: Takashi Iwai [mailto:tiwai at suse.de]
> > Sent: Thursday, August 30, 2012 10:45 PM
> > 
> > Yeah, the check seems slipped from my previous post by some reason.
> > Maybe I cherry-picked a wrong branch.
> > It should be
> > 	if (codec->power_on)
> > 		hda_call_pm_notify(codec->bus, false); and it should be called
> > before module_put().
> > 
> > It's not needed.  In the case of snd_hda_codec_free(), the only interest is
> > whether pm_notify down was already called for this this particular codec.
> > And this can be checked by codec->power_on flag.
> > 
> 
> Yes, an extra power flag is not needed. 
> 
> I think 'codec->d3_stop_clk_ok' flag is more suitable than 'codec->power_on' for this check:
> if (!codec->d3_stop_clk_ok)				... either not suspended or d3_stop_clk_ok is not set for last suspending
> 	hda_call_pm_notify(codec->bus, false);

Right, this should be something like that.

It's overall confusing to check codec->d3_stop_clk_ok at that point,
though.  And the confusion comes from the fact that we are using this
flag for multiple purposes -- the flag indicating the hardware status
and the flag indicating whether the pm-notification has been done.

So I did a few clean ups in my tree now.  Essentially I replaced
codec->d3_stop_clk_ok with codec->pm_down_notified to make the meaning
clearer.  Also the check of D3_STOP_CLK_OK bit was moved to the
hda_power_down_work() so that it's performed only in the power save.


thanks,

Takashi