[alsa-devel] iMX6UL EVK with kernel 4.6

[Petr Kulhavy]

On 01/05/16 21:22, Fabio Estevam wrote:
> On Sun, May 1, 2016 at 3:59 PM, Petr Kulhavy <brain at jikos.cz> wrote:
>
>> I have not tried setting the bit 20 of the GPR1 register. How would that be
>> set?
> If you have memtool installed in your rootfs:
>
> ./memtool -32 20E4004=0F560005
>
> You can do this via bootloader prompt or via devmem2 in the Linux prompt.
>
> Without this MCLK will not be out.
Thanks, I'll check that out.

>> Both the 3.x and 4.1 work for me. However you need to set the headphone
>> volume to non-zero and especially the pcm output mixer (unmute),
>> otherwise the audio path is not routed through and the codec is switched off
>> due to power saving (and generates no bclk and lrclk).
>> This confused me as well, but after setting the mixer playback stasrts
>> working with the Freescale kernel.
> I was putting the volume to a suitable value, but didn't touch PCM output mixer.
>
> I see in alsamixer: "PCM Playback -6dB [Off]", but it does not allow
> me to change this setting though.

The controls to unmute are:

Left Output Mixer PCM [Off]
Right Output Mixer PCM [Off]

Petr