[alsa-devel] [PATCH] ALSA: usb-audio: fix Line6 Helix audio format rates

[Takashi Iwai]

On Tue, 02 Jul 2019 02:43:14 +0200,
Nicola Lunghi wrote:
> 
> Line6 Helix and HX stomp don't support retrieving
> the number of clock sample rate.
> 
> Add a quirk to return the default value of 48Khz.
> 
> Signed-off-by: Nicola Lunghi <nick83ola at gmail.com>

It's not particularly good place to put a quirk, but there seems no
other better place, unfortunately.  Is this specific to certain unit
or all I/Os on the device suffer from this problem?

In anyway, if the behavior is expected, we don't need to use
dev_warn() to annoy users unnecessarily.  Replace it with dev_info().

Also, the code that creates a single 48k entry would be better to be
put into a function for readability.

Could you resubmit with that change?


Thanks!

Takashi

> ---
>  sound/usb/format.c | 28 +++++++++++++++++++++++++---
>  1 file changed, 25 insertions(+), 3 deletions(-)
> 
> diff --git a/sound/usb/format.c b/sound/usb/format.c
> index c02b51a82775..05442f6ada62 100644
> --- a/sound/usb/format.c
> +++ b/sound/usb/format.c
> @@ -313,10 +313,32 @@ static int parse_audio_format_rates_v2v3(struct snd_usb_audio *chip,
>  			      tmp, sizeof(tmp));
>  
>  	if (ret < 0) {
> -		dev_err(&dev->dev,
> -			"%s(): unable to retrieve number of sample rates (clock %d)\n",
> +		switch (chip->usb_id) {
> +		/* LINE 6 HX pedals don't support getting the clock sample rate.
> +		 * Set the framerate to 48khz by default
> +		 */
> +		case USB_ID(0x0E41, 0x4244): /* HELIX */
> +		case USB_ID(0x0E41, 0x4246): /* HX STOMP */
> +			dev_warn(&dev->dev,
> +				"%s(): line6 helix: unable to retrieve number of sample rates. Set it to default value (clock %d).\n",
>  				__func__, clock);
> -		goto err;
> +			fp->nr_rates = 1;
> +			fp->rate_min = 48000;
> +			fp->rate_max = 48000;
> +			fp->rates = SNDRV_PCM_RATE_48000;
> +			fp->rate_table = kmalloc(sizeof(int), GFP_KERNEL);
> +			if (!fp->rate_table) {
> +				ret = -ENOMEM;
> +				goto err_free;
> +			}
> +			fp->rate_table[0] = 48000;
> +			return 0;
> +		default:
> +			dev_err(&dev->dev,
> +				"%s(): unable to retrieve number of sample rates (clock %d)\n",
> +					__func__, clock);
> +			goto err;
> +		}
>  	}
>  
>  	nr_triplets = (tmp[1] << 8) | tmp[0];
> -- 
> 2.19.1
> 
>