The Creative Audigy SE (SB0570) card currently exhibits an audible pop whenever playback is stopped or resumed, or during silent periods of an audio stream. Initialise the IZD bit to the 0 to eliminate these pops.
The Infinite Zero Detection (IZD) feature on the DAC causes the output to be shunted to Vcap after 2048 samples of silence. This discharges the AC coupling capacitor through the output and causes the aforementioned pop/click noise.
The behaviour of the IZD bit is described on page 15 of the WM8768GEDS datasheet: "With IZD=1, applying MUTE for 1024 consecutive input samples will cause all outputs to be connected directly to VCAP. This also happens if 2048 consecutive zero input samples are applied to all 6 channels, and IZD=0. It will be removed as soon as any channel receives a non-zero input". I believe the second sentence might be referring to IZD=1 instead of IZD=0 given the observed behaviour of the card.
This change should make the DAC initialisation consistent with Creative's Windows driver, as this popping persists when initialising the card in Linux and soft rebooting into Windows, but is not present on a cold boot to Windows.
Signed-off-by: Alex Stanoev alex@astanoev.com --- sound/pci/ca0106/ca0106.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/sound/pci/ca0106/ca0106.h b/sound/pci/ca0106/ca0106.h index 04402c14cb23..9847b669cf3c 100644 --- a/sound/pci/ca0106/ca0106.h +++ b/sound/pci/ca0106/ca0106.h @@ -582,7 +582,7 @@ #define SPI_PL_BIT_R_R (2<<7) /* right channel = right */ #define SPI_PL_BIT_R_C (3<<7) /* right channel = (L+R)/2 */ #define SPI_IZD_REG 2 -#define SPI_IZD_BIT (1<<4) /* infinite zero detect */ +#define SPI_IZD_BIT (0<<4) /* infinite zero detect */
#define SPI_FMT_REG 3 #define SPI_FMT_BIT_RJ (0<<0) /* right justified mode */