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>
diff --git a/sound/pci/oxygen/hifier.c b/sound/pci/oxygen/hifier.c
index 7442460..dad393a 100644
--- a/sound/pci/oxygen/hifier.c
+++ b/sound/pci/oxygen/hifier.c
@@ -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 @@
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);