linux-kernel - Re: [RFC] ALSA: usb-audio: reduce "cannot get freq at ep" spew

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Date:	Sat, 04 Apr 2015 14:13:02 +0200
From:	Takashi Iwai <tiwai@...e.de>
To:	Eric Wong <normalperson@...t.net>
Cc:	Joe Turner <joe@...po.co.uk>, alsa-devel@...a-project.org,
	linux-kernel@...r.kernel.org
Subject: Re: [RFC] ALSA: usb-audio: reduce "cannot get freq at ep" spew

At Tue, 31 Mar 2015 07:36:28 +0000,
Eric Wong wrote:
> 
> Eric Wong <normalperson@...t.net> wrote:
> >   I also had another generic patch prepared before I noticed Joe's
> >   quirk addition for the MS Lifecam HD-5000.
> 
> This is the generic patch I prepared before I noticed Joe's quirk
> addition (applies cleanly to 3.19 and 4.0-rc6):
> 
> ------------------------------8<---------------------------
> Subject: [PATCH] ALSA: usb-audio: reduce "cannot get freq at ep" spew
> 
> If a device fails to support reading the sample rate, it will likely
> fail again and there is no point in logging the message every time the
> sample rate is set.
> 
> This reduces dmesg noise when using the Benchmark DAC1 PRE as a USB
> sound card.

Hm, this shuts up all the rest for the device, so it also hides if the
message comes from multiple EPs.


Takashi

> 
> Signed-off-by: Eric Wong <normalperson@...t.net>
> ---
>  sound/usb/clock.c    | 7 +++++--
>  sound/usb/usbaudio.h | 3 ++-
>  2 files changed, 7 insertions(+), 3 deletions(-)
> 
> diff --git a/sound/usb/clock.c b/sound/usb/clock.c
> index 03fed66..512fe12 100644
> --- a/sound/usb/clock.c
> +++ b/sound/usb/clock.c
> @@ -307,8 +307,11 @@ static int set_sample_rate_v1(struct snd_usb_audio *chip, int iface,
>  				   USB_TYPE_CLASS | USB_RECIP_ENDPOINT | USB_DIR_IN,
>  				   UAC_EP_CS_ATTR_SAMPLE_RATE << 8, ep,
>  				   data, sizeof(data))) < 0) {
> -		dev_err(&dev->dev, "%d:%d: cannot get freq at ep %#x\n",
> -			iface, fmt->altsetting, ep);
> +		if (!chip->no_get_freq) {
> +			dev_err(&dev->dev, "%d:%d: cannot get freq at ep %#x\n",
> +				iface, fmt->altsetting, ep);
> +			chip->no_get_freq = 1;
> +		}
>  		return 0; /* some devices don't support reading */
>  	}
>  
> diff --git a/sound/usb/usbaudio.h b/sound/usb/usbaudio.h
> index 91d0380..be65671 100644
> --- a/sound/usb/usbaudio.h
> +++ b/sound/usb/usbaudio.h
> @@ -43,7 +43,8 @@ struct snd_usb_audio {
>  	unsigned int in_pm:1;
>  	unsigned int autosuspended:1;	
>  	unsigned int txfr_quirk:1; /* Subframe boundaries on transfers */
> -	
> +	unsigned int no_get_freq:1;
> +
>  	int num_interfaces;
>  	int num_suspended_intf;
>  
> -- 
> EW
> 
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