cmipci - utilize ADC48K44K bit

Hi.

Setting the ADC48K44K greatly improves capture quality at 48k sampling rate.

With this bit clear ADC does ZOH interpolation of every 22th sample at 48k.

At frequencies higher than 48k there ADC performs a little better with ADC48K44K bit set. At 44.1k ADC performs a little better with this bit clear.
At frequencies below 44.1k there is no difference.

Regards,
Tim.

@@ -869,6 +869,13 @@ static int snd_cmipci_pcm_prepare(struct
 	snd_cmipci_write(cm, CM_REG_CHFORMAT, val);
 	//snd_printd("cmipci: chformat = %08x\n", val);
 
+	if (!rec->is_dac && cm->chip_version) {
+		if (runtime->rate > 44100)
+			snd_cmipci_set_bit(cm, CM_REG_EXT_MISC, CM_ADC48K44K);
+		else
+			snd_cmipci_clear_bit(cm, CM_REG_EXT_MISC, CM_ADC48K44K);
+	}
+
 	rec->running = 0;
 	spin_unlock_irq(&cm->reg_lock);
 

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At Wed, 07 Nov 2007 15:08:19 +0300,

Applied to HG tree. Thanks.

Takashi