linux-kernel - Re: [PATCH 2/2 v2] ALSA: hda - Deferred probing with request_firmware

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Date:	Thu, 09 Aug 2012 16:04:51 +0200
From:	Takashi Iwai <tiwai@...e.de>
To:	David Henningsson <david.henningsson@...onical.com>
Cc:	Thierry Reding <thierry.reding@...onic-design.de>,
	alsa-devel@...a-project.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/2 v2] ALSA: hda - Deferred probing with request_firmware_nowait()

At Thu, 09 Aug 2012 15:54:04 +0200,
David Henningsson wrote:
> 
> On 08/09/2012 03:36 PM, Takashi Iwai wrote:
> > +/* callback from request_firmware_nowait() */
> > +static void azx_firmware_cb(const struct firmware *fw, void *context)
> > +{
> > +	struct snd_card *card = context;
> > +	struct azx *chip = card->private_data;
> > +	struct pci_dev *pci = chip->pci;
> > +
> > +	if (!fw) {
> > +		snd_printk(KERN_ERR SFX "Cannot load firmware, aborting\n");
> > +		goto error;
> > +	}
> 
> Another thing, aren't you missing a
> 
> chip->fw = fw;
> 
> here?

Ah, yes.


> > +
> > +	if (!chip->disabled) {
> > +		/* continue probing */
> > +		if (azx_probe_continue(chip))
> > +			goto error;
> > +	}
> > +	return; /* OK */
> > +
> > + error:
> > +	snd_card_free(card);
> > +	pci_set_drvdata(pci, NULL);
> > +}
> > +
> >   static int __devinit azx_probe(struct pci_dev *pci,
> >   			       const struct pci_device_id *pci_id)
> >   {
> >   	static int dev;
> >   	struct snd_card *card;
> >   	struct azx *chip;
> > +	bool probe_deferred;
> >   	int err;
> >
> >   	if (dev >= SNDRV_CARDS)
> > @@ -3182,18 +3211,22 @@ static int __devinit azx_probe(struct pci_dev *pci,
> >   	if (err < 0)
> >   		goto out_free;
> >   	card->private_data = chip;
> 
> Right, this patch has the race removed, as the variable is no longer set 
> in azx_firmware_cb. To be picky, it's slightly confusing that 
> probe_deferred is also used for signalling a disabled chip. Maybe 
> "probe_now" (inverted) would have been even better, like this:

Yeah, this looks slightly more straightforward.

I'm going to send a revised version shortly.


thanks,

Takashi
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