[alsa-devel] sgtl5000 fails after suspend/resume

[Max Krummenacher]

Hi Fabio

On Thu, 2018-02-15 at 14:36 -0200, Fabio Estevam wrote:
> On Thu, Feb 15, 2018 at 11:35 AM, Fabio Estevam <festevam at gmail.com> wrote:
> > 
> > Hi,
> > 
> > I noticed that sgtl5000 does not work after a suspend/resume cycle:
> > 
> > # aplay /media/a2002011001-e02.wav
> > Playing WAVE '/media/a2002011001-e02.wav' : Signed 16 bit Little
> > Endian, Rate 44100 Hz, Stereo
> > aplay: pcm_write:2051: write error: Input/output error
> > 
> > Tested several 4.16-rc1 (and also previous kernels like 4.4) and all
> > of them failed.
> > 
> > I think it worked in some point in time.
> > 
> > Tested on a imx53qsb and imx6 wandboard.
> > 
> > Does anyone have any suggestions?
> 
> Reverting the commit below on top of 4.16-rc1 makes sgtl5000
> suspend/resume to work again:
> 
> commit 8419caa7270291e26f8b34b12b29680586c85d30
> Author: Eric Nelson <eric at nelint.com>
> Date:   Tue Jun 7 01:14:52 2016 +0200
> 
>     ASoC: sgtl5000: Do not disable regulators in SND_SOC_BIAS_OFF
> 
>     Disabling the SGTL5000 through regulators would certainly save more
>     power than simply disabling the reference voltages as described in the
>     data sheet, but won't properly restore things on resume.
> 
>     This driver does not support active regulators. So we simply disable the
>     reference bias currents.
> 
>     Signed-off-by: Eric Nelson <eric at nelint.com>
>     Signed-off-by: Clemens Gruber <clemens.gruber at pqgruber.com>
>     Reviewed-by: Fabio Estevam <fabio.estevam at nxp.com>
>     Signed-off-by: Mark Brown <broonie at kernel.org>
> 
> Or if I do the change below against linux-next it also works:
> 
> --- a/sound/soc/codecs/sgtl5000.c
> +++ b/sound/soc/codecs/sgtl5000.c
> @@ -880,8 +880,6 @@ static int sgtl5000_set_bias_level(struct
> snd_soc_component *component,
>                                     SGTL5000_REFTOP_POWERUP);
>                 break;
>         case SND_SOC_BIAS_OFF:
> -               snd_soc_component_update_bits(component,
> SGTL5000_CHIP_ANA_POWER,
> -                                   SGTL5000_REFTOP_POWERUP, 0);
>                 break;
>         }
> 
> Any suggestions for a proper fix? Eric?
> 

I tested this on a Colibri iMX6DL with the same results.
Vanilla 4.16-rc1 does resume but audio is silent after resume.
The interrupted aplay process is in the process list and never finishes.

Both your fixes make aplay continue playing sound again until the end
of the played sound file.

Strangely if I use our downstream kernel (based on NXP/linux-fslc
4.9-1.0.x-imx which has the 8419caa7270291e26f8b34b12b29680586c85d30
commit) suspend/resume works.

Max