-----Original Message----- From: Kai-Heng Feng [mailto:kai.heng.feng@canonical.com] Sent: Thursday, March 23, 2017 12:42 PM To: Bard Liao Cc: broonie@kernel.org; lgirdwood@gmail.com; Oder Chiou; alsa-devel@alsa-project.org; linux-kernel@vger.kernel.org Subject: Re: [PATCH v3] ASoC: rt286: fix headphone click/crack noise on Dell XPS 9343 I2S mode
If HPO is already muted as what we expected, it means "HPO L" and "HPO R" work properly. And there is no reason we create an event to do the same thing.
Can you advise me how to do a simple check on HPO L&R mute status?
You can cat /sys/kernel/debug/regmap/<bus name>/registers And check the registers of 0x2139000 for HPOR and 0x213a000 for HPOL. bit 15 = 1 for muted and 0 for unmuted. for example Mute: 2139000: 00000080 213a000: 00000080
UnMute: 2139000: 00000000 213a000: 00000000
I found that the effect is most noticeable if the mute callback is associated with "LDO2" and "HP Power". But again, this is just what I observed.
Could you try only associated with "LDO2"? It makes sense that will reduce the noise if a jack is plugged in/out when HPO is already powered up.
Does it also help to reduce noise at other power events?
I don't know. In theory, you shouldn't hear any sound when HPO is muted. If you need our help for debugging, please send a mail to our FAE and cc me.
Unfortunately it did happen. AMP mute did well for me and another user
- please check the bug report link.
I know it happens. But it works fine on my Intel Ultrabook Development System with upstream driver. So I need our FAE's help to check what happened on Dell XPS. According to our company policy, you should report the bug to Dell and Dell will contact our FAE if needed.