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/oxygen.c b/sound/pci/oxygen/oxygen.c
index 7c8ae31..c5829d3 100644
--- a/sound/pci/oxygen/oxygen.c
+++ b/sound/pci/oxygen/oxygen.c
@@ -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 @@
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);