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authorTimofei Bondarenko <tim@ipi.ac.ru>2007-11-07 15:49:57 +0100
committerJaroslav Kysela <perex@perex.cz>2008-01-31 17:29:19 +0100
commitfeb77712b0e780f04507cdda0529088ff0f3286f (patch)
tree190b0e7a0d2a63e4f7234ad9f2352199ed364c72 /sound/pci
parentb98f9334e25c463fbfbb1cc468c66845e1c8e46a (diff)
[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>
Diffstat (limited to 'sound/pci')
-rw-r--r--sound/pci/cmipci.c7
1 files changed, 7 insertions, 0 deletions
diff --git a/sound/pci/cmipci.c b/sound/pci/cmipci.c
index 3a2d942f22b..d1f23ebed2a 100644
--- 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);