[ALSA] cmipci - utilize ADC48K44K bit

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.

Signed-off-by: Timofei Bondarenko <tim@ipi.ac.ru>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>

diff --git a/sound/pci/cmipci.c b/sound/pci/cmipci.c
index 3a2d942f22bb777c00dfffdb7771c40d19bfa98c..d1f23ebed2ae5608a92666803c0db3dfc54a39b0 100644 (file)
--- a/sound/pci/cmipci.c
+++ b/sound/pci/cmipci.c
@@ -869,6 +869,13 @@ static int snd_cmipci_pcm_prepare(struct cmipci *cm, struct cmipci_pcm *rec,
        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);