rt5640 output stays off when switched off and on again.

[rafirafi]

Hi,

The device is a meegopad t02, a compute stick with only a headset jack and hdmi output.
I'm using xubuntu 16.04, pulseaudio 8.0, pavucontrol 3.0 with the most recent ucm files.

In pavucontrol I begin with a working sound :
in tab 'Configuration' bytcr-rt5640 output is set to 'Play Hifi quality Music'
in tab 'Output Devices' Port is set to 'Headphones playback'

In pavucontrol in 'Configuration' if I set bytcr-rt5640 output to 'Off'
and then set it back to 'Play Hifi quality Music' the sound doesn't come back.

I found a forum where someone with another device was having the same issue
and it turns out that it is possible to have the sound working again with :

alsaucm -n -b - <<EOM
open bytcr-rt5640
reset
set _verb HiFi
set _enadev Headphones
EOM

From the alsaucm manpage this looks like this is just selecting the output,
shouldn't this be done automatically by pulseaudio (via pavucontrol) when
bytcr-rt5640 output is set to 'On'?

Regards.

[rafirafi]

Any idea to where the problem may come?
I would really appreciate any help to narrow it down, or is it more appropriate to file a bug report to the kernel for the rt5640 module or to alsa or pulseaudio ?