RE: [PATCH 2/6] ASoC: amd: yc: Add a module parameter to influence pdm_gain

[Limonciello, Mario]

[AMD Official Use Only - General]



> -----Original Message-----
> From: Jaroslav Kysela <perex@xxxxxxxx>
> Sent: Friday, January 27, 2023 10:23
> To: Limonciello, Mario <Mario.Limonciello@xxxxxxx>; Mukunda, Vijendar
> <Vijendar.Mukunda@xxxxxxx>; Saba Kareem, Syed
> <Syed.SabaKareem@xxxxxxx>; linux-kernel@xxxxxxxxxxxxxxx
> Cc: Pananchikkal, Renjith <Renjith.Pananchikkal@xxxxxxx>; Mark Pearson
> <mpearson@xxxxxxxxxx>; Liam Girdwood <lgirdwood@xxxxxxxxx>; Mark
> Brown <broonie@xxxxxxxxxx>; Takashi Iwai <tiwai@xxxxxxxx>; alsa-
> devel@xxxxxxxxxxxxxxxx
> Subject: Re: [PATCH 2/6] ASoC: amd: yc: Add a module parameter to
> influence pdm_gain
> 
> On 27. 01. 23 17:01, Mario Limonciello wrote:
> > In case of regressions for any users that the new pdm_gain value is
> > too high and for additional debugging, introduce a module parameter
> > that would let them configure it.
> >
> > Signed-off-by: Mario Limonciello <mario.limonciello@xxxxxxx>
> > ---
> >   sound/soc/amd/yc/acp6x-pdm-dma.c | 7 ++++++-
> >   sound/soc/amd/yc/acp6x.h         | 2 +-
> >   2 files changed, 7 insertions(+), 2 deletions(-)
> 
> ...
> 
> >   	pdm_ctrl = acp6x_readl(acp_base + ACP_WOV_MISC_CTRL);
> > -	pdm_ctrl |= ACP_WOV_MISC_CTRL_MASK;
> > +	pdm_ctrl |= FIELD_PREP(ACP_WOV_GAIN_CONTROL, pdm_gain);
> 
> The bits should be zeroed (AND - &) before OR to make sure that the correct
> value is written to the register. More related patches are affected.

I had consider this, but the hardware default at reset is 0x0.  Do you think it's
still necessary for posterity?