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

[Yang, Libin]

> -----Original Message-----
> From: Takashi Iwai [mailto:tiwai at suse.de]
> Sent: Tuesday, July 28, 2015 1:39 PM
> To: Eoff, Ullysses A
> Cc: alsa-devel at alsa-project.org; Lee, Zhuo-hao; Yang, Libin
> Subject: Re: [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.

As, in runtime_resume will call azx_init_chip(), which may sleep,
is there any race when calling azx_runtime_resume(), 
azx_runtime_idle is called and enter azx_runtime_suspend()?
Or the ACPI subsystem will handle such situation?

> 
> 
> thanks,
> 
> Takashi