Re: [PATCH 1/3] ALSA - hda: Add support for GTS capability

From: Takashi Iwai <tiwai@suse.de>
To: Vinod Koul <vinod.koul@intel.com>
Cc: alsa-devel@alsa-project.org, patches.audio@intel.com,
	Hardik T Shah <hardik.t.shah@intel.com>,
	Guneshwor Singh <guneshwor.o.singh@intel.com>,
	liam.r.girdwood@linux.intel.com, broonie@kernel.org
Subject: Re: [PATCH 1/3] ALSA - hda: Add support for GTS capability
Date: Mon, 11 Jul 2016 16:06:25 +0200	[thread overview]
Message-ID: <s5ha8hotgke.wl-tiwai@suse.de> (raw)
In-Reply-To: <20160711140732.GH9681@localhost>

On Mon, 11 Jul 2016 16:07:32 +0200,
Vinod Koul wrote:
> 
> > > diff --git a/sound/pci/hda/hda_intel.c b/sound/pci/hda/hda_intel.c
> > > index 9a0d1445ca5c..b4ebdde59398 100644
> > > --- a/sound/pci/hda/hda_intel.c
> > > +++ b/sound/pci/hda/hda_intel.c
> > > @@ -1649,6 +1649,7 @@ static int azx_first_init(struct azx *chip)
> > >  		return -ENXIO;
> > >  	}
> > >  
> > > +	azx_parse_capabilities(chip);
> > 
> > Is it really safe to call the function no matter which chip?
> 
> I think so, since we read base HDA registers for capablity. For older hw the
> next capablity will not be there.
> 
> But yes I will verify this on older machines.

I checked the spec 1.0 and 1.0a, and there is no definition for the
register offset 0x14.  So, it's likely unsafe to use it
unconditionally.

Takashi