From: Marco Felsch <m.felsch@xxxxxxxxxxxxxx> According the datasheets [1], [2] the initial value of register 0x2f/0x31 (dai1/dai2) is 0x00 which means that dai is unmuted. So upon the first playback request the register is not touched since it is cached by regmap. But the device output keeps silent. After ending the playback session the mute() callback updates the register. Now the 2nd playback request updates the register again (-> unmute the device) and now we can really hear the output signal. I've checked the register initial value which is '0x00' so the driver is correct. Accroding the above inspections it seems that the hardware does not update the register correctly on power up because the output is muted. To fix that we need to explicit set the mute state. Now the first playback request gets played correctly. [1] https://datasheets.maximintegrated.com/en/ds/MAX98089.pdf [2] https://datasheets.maximintegrated.com/en/ds/MAX98088.pdf Signed-off-by: Marco Felsch <m.felsch@xxxxxxxxxxxxxx> --- sound/soc/codecs/max98088.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/sound/soc/codecs/max98088.c b/sound/soc/codecs/max98088.c index 7f108e147355..c00d7726ac04 100644 --- a/sound/soc/codecs/max98088.c +++ b/sound/soc/codecs/max98088.c @@ -1710,6 +1710,11 @@ static int max98088_probe(struct snd_soc_component *component) snd_soc_component_write(component, M98088_REG_1E_DAI2_IOCFG, M98088_S2NORMAL|M98088_SDATA); + snd_soc_component_update_bits(component, M98088_REG_2F_LVL_DAI1_PLAY, + M98088_DAI_MUTE_MASK, M98088_DAI_MUTE); + snd_soc_component_update_bits(component, M98088_REG_31_LVL_DAI2_PLAY, + M98088_DAI_MUTE_MASK, M98088_DAI_MUTE); + max98088_handle_pdata(component); err_access: -- 2.38.1
