Re: ATI IXP Modem driver

[Sasha Khapyorsky <sashak@smlink.com>]

On Wed, 28 Jul 2004 18:26:25 +0200
Takashi Iwai <tiwai@suse.de> wrote:

> 
> Well, this will be still a problem when the audio driver is loaded
> after the modem driver.  We'll need a way to avoid the double reset on
> codecs.
> 
> How about adding a new flag to ac97 struct to indicate the shared chip
> type? 

Basically ac97 (or even ac97_bus) 'sharing' is good idea - it better
represents the real configuration.


> ac97_codec.c holds a static array, such as
> 
> 	static ac97_t *ac97_shared_codec[AC97_NUM_SHARED_CHIPS][4];
> 
> and when ac97->shared is non-zero, check the existence of the
> already-initialized codec first,
> 	if (ac97->shared && ac97_shared_codec[ac97->shared][ac97->num])
> 	{
> 		if (modem_only)
> 			...
> 		if (audio_only)
> 			...
> 	}
> 
> and set it when ready
> 	if (ac97->shared)
> 		ac97_shared_codec[ac97->shared][ac97->num] = ac97;
> 
> release it in snd_ac97_free(),
> 	if (ac97->shared)
> 		ac97_shared_codec[ac97->shared][ac97->num] = NULL;
> 
> Most likely we'll need to protect the above with mutex.

But one question about such implementation. What non-zero
'ac97-shared' should mean as index: How many shared chips will be
possible? If more that one (AC97_NUM_SHARED_CHIPS > 1), which initial
value should be used by driver? I mean how driver will know how much
'shared' buses are already in use?

Sasha.


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