[ALSA] ac97 - Suppress the reset of audio-codec from modem-codec at resume

On codec chips with both audio and modem functions (e.g. Conexant one),
performing AC97_RESET resets the whole registers.  When both audio and
modem drivers are resumed at the same time, the modem one often is
resumed after the audio, and it results in the reset of audio registers
(ALSA bug#3333).
This patch fixes such a problem.  Since the modem codec basically
doesn't need AC97_RESET, skip this initialization unless specified
as audio.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>

sound/pci/ac97/ac97_codec.c

@@ -2496,7 +2496,10 @@ void snd_ac97_resume(struct snd_ac97 *ac97)
 
 	snd_ac97_write(ac97, AC97_POWERDOWN, 0);
 	if (! (ac97->flags & AC97_DEFAULT_POWER_OFF)) {
-		snd_ac97_write(ac97, AC97_RESET, 0);
+		if (!(ac97->scaps & AC97_SCAP_SKIP_AUDIO))
+			snd_ac97_write(ac97, AC97_RESET, 0);
+		else if (!(ac97->scaps & AC97_SCAP_SKIP_MODEM))
+			snd_ac97_write(ac97, AC97_EXTENDED_MID, 0);
 		udelay(100);
 		snd_ac97_write(ac97, AC97_POWERDOWN, 0);
 	}