[alsa-devel] Fixes in intel8x0.c

[Takashi Iwai]

At Tue, 26 May 2009 01:19:06 +0200,
Pavel Hofman wrote:
> 
> Hi,
> 
> while trying to dive into complexities of intel8x0.c I found the following:
> 
> static struct snd_pci_quirk intel8x0_clock_list[] __devinitdata = {
> 	SND_PCI_QUIRK(0x0e11, 0x008a, "AD1885", 41000),
> 	SND_PCI_QUIRK(0x1028, 0x00be, "AD1885", 44100),
> .....
> 
> Is it really supposed to be 41000, instead of 44100?

Looks like so, judging from the patch Jaroslav wrote.

> In static int snd_intel8x0_pcm_open(struct snd_pcm_substream *substream,
> struct ichdev *ichdev)
> ...
> 	runtime->hw.rates = ichdev->pcm->rates;
> 
> The pcm field in ichdev is snd_ac97, while the rates field in snd_ac97
> is defined
> 
> unsigned int rates[6];	/* see AC97_RATES_* defines */
> 
> I guess this way always rates[0] from the list is taken, unlike e.g. in
> via82xx.c: runtime->hw.rates = chip->ac97->rates[AC97_RATES_SPDIF];

41000 is the base clock.  The actual rate written is

	rate * clock / 48000

Normally the base clock is 48000.  But some boards have a different
base clock and the rate has to be adjusted to match with that.


Takashi