[alsa-devel] Fixes in intel8x0.c

[Pavel Hofman]

Takashi Iwai wrote:
> 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?

Sorry, my fault, I confused ac97_pcm with snd_ac97.

Thanks,

Pavel.