RE: [PATCH] ALSA: hda: cs35l56: Stop creating ALSA controls for firmware coefficients

[Simon Trimmer]

Apologies Takashi - can you ignore this one please? It will need a V2

> -----Original Message-----
> From: Simon Trimmer <simont@xxxxxxxxxxxxxxxxxxxxx>
> Sent: Monday, July 29, 2024 5:16 PM
> To: tiwai@xxxxxxxx
> Cc: linux-sound@xxxxxxxxxxxxxxx; alsa-devel@xxxxxxxxxxxxxxxx; linux-
> kernel@xxxxxxxxxxxxxxx; patches@xxxxxxxxxxxxxxxxxxxxx; Simon Trimmer
> <simont@xxxxxxxxxxxxxxxxxxxxx>
> 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@xxxxxxxxxxxxxxxxxxxxx>
> ---
>  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