[alsa-devel] [PATCH] Add volume resolution quirk for some logitech webcams

[Daniel Mack]

On Wed, Jun 23, 2010 at 11:34:47AM +0200, Alexey Fisher wrote:
> Some programs like Skype trying to set capture volume automatically.
> Normally it will tray carefully, step by step lover or higher the volume.
> In real word it work not really well, because devises and vendors lie
> about real audio settings. For example most Logitech webcams
> have 6400 or 3500 steps for capture volume. They do not tell that
> actual resolution is 384. So we have only 7 or 18 real steps.
> In this patch I set real resolution only for tested devices.
> 
> Signed-off-by: Alexey Fisher <bug-track at fisher-privat.net>
> ---
>  sound/usb/mixer.c |   12 ++++++++++++
>  1 files changed, 12 insertions(+), 0 deletions(-)
> 
> diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c
> index 6939d0f..fd9f377 100644
> --- a/sound/usb/mixer.c
> +++ b/sound/usb/mixer.c
> @@ -1107,6 +1107,18 @@ static void build_feature_ctl(struct mixer_build *state, void *raw_desc,
>  		}
>  		break;
>  
> +	case USB_ID(0x046d, 0x0809):
> +	case USB_ID(0x046d, 0x0991):
> +	/* most audio usb divise lighe about volume resolution.
> +	 * most of them have res = 384. Proboly there is some magick behind
> +	 * this number. */

While the change itself is acceptable, there are too many typos in this
comment ;) Can you please fix them up, please?

Thanks,
Daniel


> +		if (!strcmp(kctl->id.name, "Mic Capture Volume")) {
> +			snd_printk(KERN_INFO
> +				"set volume quirk: cval->res = 384\n");
> +			cval->res = 384;
> +		}
> +		break;
> +
>  	}
>  
>  	snd_printdd(KERN_INFO "[%d] FU [%s] ch = %d, val = %d/%d/%d\n",
> -- 
> 1.7.0.4
> 
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