[alsa-devel] [PATCH v2 1/2] ALSA - hda: Add support for parsing new HDA capabilities

[Vinod Koul]

On Wed, Jul 20, 2016 at 07:31:17AM +0200, Takashi Iwai wrote:

> > +	unsigned int offset; unsigned int counter = 0;
> 
> Need a line break.

arghh, will fix..

> > +	offset = azx_readl(chip, LLCH);
> > +
> > +	/* Lets walk the linked capabilities list */
> > +	do {
> > +		cur_cap = _snd_hdac_chip_read(l, azx_bus(chip), offset);
> > +
> > +		switch ((cur_cap & CAP_HDR_ID_MASK) >> CAP_HDR_ID_OFF) {
> > +		case GTS_CAP_ID:
> > +			dev_dbg(chip->card->dev, "Found GTS capability");
> > +			chip->gts_present = 1;
> > +			break;
> > +
> > +		default:
> > +			break;
> > +		}
> > +
> > +		counter++;
> > +
> > +		if (counter > AZX_MAX_CAPS) {
> > +			dev_err(chip->card->dev, "We exceeded azx capabilities!!!\n");
> > +			break;
> > +		}
> > +
> > +		/* read the offset of next capabiity */
> > +		offset = cur_cap & CAP_HDR_NXT_PTR_MASK;
> > +
> > +	} while (offset);
> 
> Wouldn't it be safer to use a normal while () {} loop?
> The first LLCH read might be zero, in theory.

Then in that case first read will give error. But yes I see the benifits.

Btw this is same as snd_hdac_ext_bus_parse_capabilities()

Should we move this to hdac and use for both. Ofcourse many new capablities
do not make sense to legacy driver, so we would have to ignore them.

> > +	if (!(chip->gts_present && boot_cpu_has(X86_FEATURE_ART)))
> > +		chip->gts_present = false;
> 
> Need #ifdef CONFIG_X86 guard here, too.
> Also, the inclusion of <asm/cpufeature.h> isn't needed?  (Again
> X86-only.)

This is intel.c :) I did compile it for ARM before sending.

-- 
~Vinod