[alsa-devel] Fixes in intel8x0.c

[Takashi Iwai]

At Tue, 26 May 2009 10:09:57 +0200,
Pavel Hofman wrote:
> 
> Takashi Iwai wrote:
> > 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, thanks for your answer, 41000 is OK.
> 
> How about the second question regarding the assignment of rates field
> being an array? I am remotely troubleshooting SPDIF output of Dell D600
> which seems to be stuck at 48kHz (plughw always resamples to 48kHz, even
> though the analog  PCM accepts 44.1kHz. The above mentioned code is
> related to this (not exactly the cause though.

I don't see any problem in the code.  Are you sure that it's really related?


Takashi