[alsa-devel] [PATCH 1/2] ALSA: hda - skip runtime PM if async probe is not finished

[Eoff, Ullysses A]

> -----Original Message-----
> From: alsa-devel-bounces at alsa-project.org [mailto:alsa-devel-bounces at alsa-project.org] On Behalf Of Takashi Iwai
> Sent: Monday, July 27, 2015 10:39 PM
> To: Eoff, Ullysses A
> Cc: Yang, Libin; alsa-devel at alsa-project.org; Lee, Zhuo-hao
> Subject: Re: [alsa-devel] [PATCH 1/2] ALSA: hda - skip runtime PM if async probe is not finished
> 
> On Mon, 27 Jul 2015 23:34:53 +0200,
> U. Artie Eoff wrote:
> >
> > Crash can occur if runtime PM is triggered before the async probe
> > finishes via the azx_firmware_cb when CONFIG_SND_HDA_PATCH_LOADER
> > is defined.
> >
> > Don't execute PM ops if the async probe has not completed yet.
> >
> > The probe is finished when chip->running is true.
> >
> > Signed-off-by: U. Artie Eoff <ullysses.a.eoff at intel.com>
> > ---
> >  sound/pci/hda/hda_intel.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/sound/pci/hda/hda_intel.c b/sound/pci/hda/hda_intel.c
> > index 735bdcb04ce8..b729b25a6ad6 100644
> > --- a/sound/pci/hda/hda_intel.c
> > +++ b/sound/pci/hda/hda_intel.c
> > @@ -1023,7 +1023,7 @@ static int azx_runtime_idle(struct device *dev)
> >
> >  	chip = card->private_data;
> >  	hda = container_of(chip, struct hda_intel, chip);
> > -	if (chip->disabled || hda->init_failed)
> > +	if (chip->disabled || hda->init_failed || !chip->running)
> >  		return 0;
> 
> For !chip->running, it's better to return -EBUSY.
> 
> The disabled and init_failed flags are checked in runtime_suspend()
> and runtime_resume() to skip the whole procedures, too.
> 
> And I guess the check of chip->running should suffice even without the
> second patch.  It assures that the bus is powered on.
>

Ok, I will test your suggested change to see if it addresses
both elusive race conditions and report back.  It sounds like
it'll be the right fix.  Thanks for the feedback.

U. Artie
 
> 
> thanks,
> 
> Takashi
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