Thinkpad Helix 2 is a tablet PC, the audio is powered by Core M broadwell-audio and rt286 codec. For all versions of Linux kernel, the stereo output doesn't work properly when earphones are plugged in, the sound was coming out from both channels even if the audio contains only the left or right channel. Furthermore, if a music recorded in stereo is played, the two channels cancle out each other out, as a result, no voice but only distorted background music can be heard, like a sound card with builtin a Karaoke sount effect.
Apparently this tablet uses a combo jack with polarity incorrectly set by rt286 driver. This patch adds DMI information of Thinkpad Helix 2 to force_combo_jack_table[] and the issue is resolved. The microphone input doesn't work regardless to the presence of this patch and still needs help from other developers to investigate.
This is my first patch to LKML directly, sorry for CC-ing too many people here.
Link: https://bugzilla.kernel.org/show_bug.cgi?id=93841 Cc: Bard Liao bardliao@realtek.com Cc: Oder Chiou oder_chiou@realtek.com Cc: Mark Brown broonie@kernel.org Cc: Keyon yang.jie@linux.intel.com Cc: Jinliang Wang jinliangx.wang@intel.com Cc: stable@vger.kernel.org Signed-off-by: Yifeng Li tomli@tomli.me --- sound/soc/codecs/rt286.c | 7 +++++++ 1 file changed, 7 insertions(+)
diff --git a/sound/soc/codecs/rt286.c b/sound/soc/codecs/rt286.c index 9c365a7f758d..7899a2cdeb42 100644 --- a/sound/soc/codecs/rt286.c +++ b/sound/soc/codecs/rt286.c @@ -1108,6 +1108,13 @@ static const struct dmi_system_id force_combo_jack_table[] = { DMI_MATCH(DMI_PRODUCT_NAME, "Kabylake Client platform") } }, + { + .ident = "Thinkpad Helix 2nd", + .matches = { + DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"), + DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad Helix 2nd") + } + },
{ } };