Messages in this thread Patch in this message | | | Date | Mon, 6 Oct 2008 17:38:04 -0700 | From | Greg KH <> | Subject | [patch 14/71] ALSA: oxygen: fix distorted output on AK4396-based cards |
| |
2.6.26-stable review patch. If anyone has any objections, please let us know.
------------------ From: Clemens Ladisch <clemens@ladisch.de>
Upstream-commit-id: df91bc23dcb052ff2da71b3482bf3c5fbf4b8a53
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> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- sound/pci/oxygen/hifier.c | 4 ++++ sound/pci/oxygen/oxygen.c | 4 ++++ 2 files changed, 8 insertions(+)
--- 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> @@ -95,6 +96,9 @@ static void set_ak4396_params(struct oxy 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); --- 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> @@ -173,6 +174,9 @@ static void set_ak4396_params(struct oxy 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); --
| |