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ALSA: oxygen: fix distorted output on AK4396-based cards 

When changing the sample rate, the CMI8788's master clock output becomes
unstable for a short time.  The AK4396 needs the master clock to do SPI
writes, so writing to an AK4396 control register directly after a sample
rate change will garble the value.  In our case, this leads to the DACs
being misconfigured to I2S sample format, which results in a wrong
output level and horrible distortions on samples louder than -6 dB.

To fix this, we need to wait until the new master clock signal has
become stable before doing SPI writes.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Clemens Ladisch 2008-08-29 13:08:34 +02:00 committed by Takashi Iwai
parent 93a1a5eb70
commit df91bc23dc
2 changed files with 8 additions and 0 deletions
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4
sound/pci/oxygen/hifier.c
View File

@ -17,6 +17,7 @@
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <linux/delay.h>
#include <linux/pci.h>
#include <sound/control.h>
#include <sound/core.h>
@ -107,6 +108,9 @@ static void set_ak4396_params(struct oxygen *chip,
else
value |= AK4396_DFS_QUAD;
data->ak4396_ctl2 = value;
msleep(1); /* wait for the new MCLK to become stable */
ak4396_write(chip, AK4396_CONTROL_1, AK4396_DIF_24_MSB);
ak4396_write(chip, AK4396_CONTROL_2, value);
ak4396_write(chip, AK4396_CONTROL_1, AK4396_DIF_24_MSB | AK4396_RSTN);

4
sound/pci/oxygen/oxygen.c
View File

@ -28,6 +28,7 @@
* GPIO 1 -> DFS1 of AK5385
*/
#include <linux/delay.h>
#include <linux/mutex.h>
#include <linux/pci.h>
#include <sound/ac97_codec.h>
@ -213,6 +214,9 @@ static void set_ak4396_params(struct oxygen *chip,
else
value |= AK4396_DFS_QUAD;
data->ak4396_ctl2 = value;
msleep(1); /* wait for the new MCLK to become stable */
for (i = 0; i < 4; ++i) {
ak4396_write(chip, i,
AK4396_CONTROL_1, AK4396_DIF_24_MSB);