linux-kernel - Re: [PATCH] ALSA: hda: cs35l56: Stop creating ALSA controls for firmware coefficients

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Message-ID: <87jzh49exl.wl-tiwai@suse.de>
Date: Mon, 29 Jul 2024 21:27:34 +0200
From: Takashi Iwai <tiwai@...e.de>
To: Simon Trimmer <simont@...nsource.cirrus.com>
Cc: <tiwai@...e.com>,
	<linux-sound@...r.kernel.org>,
	<alsa-devel@...a-project.org>,
	<linux-kernel@...r.kernel.org>,
	<patches@...nsource.cirrus.com>
Subject: Re: [PATCH] ALSA: hda: cs35l56: Stop creating ALSA controls for firmware coefficients

On Mon, 29 Jul 2024 19:14:13 +0200,
Simon Trimmer wrote:
> 
> Apologies Takashi - can you ignore this one please? It will need a V2

Sure.


thanks,

Takashi

> 
> > -----Original Message-----
> > From: Simon Trimmer <simont@...nsource.cirrus.com>
> > Sent: Monday, July 29, 2024 5:16 PM
> > To: tiwai@...e.com
> > Cc: linux-sound@...r.kernel.org; alsa-devel@...a-project.org; linux-
> > kernel@...r.kernel.org; patches@...nsource.cirrus.com; Simon Trimmer
> > <simont@...nsource.cirrus.com>
> > Subject: [PATCH] ALSA: hda: cs35l56: Stop creating ALSA controls for
> firmware
> > coefficients
> > 
> > A number of laptops have gone to market with old firmware versions that
> > export controls that have since been hidden, but we can't just install a
> > newer firmware because the firmware for each product is customized and
> > qualified by the OEM. The issue is that alsactl save and restore has no
> > idea what controls are good to persist which can lead to
> > misconfiguration.
> > 
> > As the ALSA controls for the firmware coefficients are not used in
> > normal operation they can all be hidden, but add a kernel parameter so
> > that they can be re-enabled for debugging.
> > 
> > Fixes: 73cfbfa9caea ("ALSA: hda/cs35l56: Add driver for Cirrus Logic
> CS35L56
> > amplifier")
> > Signed-off-by: Simon Trimmer <simont@...nsource.cirrus.com>
> > ---
> >  sound/pci/hda/cs35l56_hda.c | 7 +++++++
> >  1 file changed, 7 insertions(+)
> > 
> > diff --git a/sound/pci/hda/cs35l56_hda.c b/sound/pci/hda/cs35l56_hda.c
> > index 96d3f13c5abf..1494383b22c9 100644
> > --- a/sound/pci/hda/cs35l56_hda.c
> > +++ b/sound/pci/hda/cs35l56_hda.c
> > @@ -23,6 +23,10 @@
> >  #include "hda_cs_dsp_ctl.h"
> >  #include "hda_generic.h"
> > 
> > +static bool expose_dsp_controls;
> > +module_param(expose_dsp_controls, bool, 0444);
> > +MODULE_PARM_DESC(expose_dsp_controls, "Expose firmware controls as
> > ALSA controls 0=no (default), 1=yes");
> > +
> >   /*
> >    * The cs35l56_hda_dai_config[] reg sequence configures the device as
> >    *  ASP1_BCLK_FREQ = 3.072 MHz
> > @@ -758,6 +762,9 @@ static int cs35l56_hda_bind(struct device *dev, struct
> > device *master, void *mas
> > 
> >  	cs35l56_hda_create_controls(cs35l56);
> > 
> > +	if (expose_dsp_controls)
> > +		cs35l56_hda_add_dsp_controls(cs35l56);
> > +
> >  #if IS_ENABLED(CONFIG_SND_DEBUG)
> >  	cs35l56->debugfs_root = debugfs_create_dir(dev_name(cs35l56-
> > >base.dev), sound_debugfs_root);
> >  	cs_dsp_init_debugfs(&cs35l56->cs_dsp, cs35l56->debugfs_root);
> > --
> > 2.43.0
> 
>