Re: [PATCH 1/2] ALSA: usb-audio: Skip reading sample rate on M-Audio Venom

On Sat, 22 Aug 2026 06:30:32 +0200,
Federico Valentín Andrade wrote:
> 
> The M-Audio Venom (0763:2084) is an USB Audio Class 1 compliant
> synth with an integrated audio interface, it does not implement
> GET_CUR on SAMPLING_FREQ_CONTROL, hanging up if requested on
> endpoint 0.
> 
> The first class request issued by the driver after enumeration is
> a GET_CUR on endpoint 0x02, freezing the device's USB microcontroller.
> Timing out on every transfer afterwards with -ETIMEDOUT, such as
> SET_INTERFACE, so neither the mixer nor any streaming interface is set up.
> 
> Analyzing a USBPcap capture of the Windows driver I found it never
> requests the sampling frequency, as the synth exposes a single
> discrete of 44100Hz on both streaming interfaces, thus asking for it
> is unnecessary.
> 
> So I applied get_sample_rate to avoid this check, and
> disable_autosuspend because the synth doesn't come back from being
> suspended.
> 
> Signed-off-by: Federico Valentín Andrade <[email protected]>
> ---
>  sound/usb/quirks.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/sound/usb/quirks.c b/sound/usb/quirks.c
> index f4e1eac639..caa80487f4 100644
> --- a/sound/usb/quirks.c
> +++ b/sound/usb/quirks.c
> @@ -2334,6 +2334,8 @@ static const struct usb_audio_quirk_flags_table quirk_flags_table[] = {
>  		   QUIRK_FLAG_MIXER_GET_CUR_BROKEN | QUIRK_FLAG_GENERIC_IMPLICIT_FB),
>  	DEVICE_FLG(0x0763, 0x2081, /* M-Audio Fast Track Ultra */
>  		   QUIRK_FLAG_MIXER_GET_CUR_BROKEN | QUIRK_FLAG_GENERIC_IMPLICIT_FB),
> +	DEVICE_FLG(0x0763, 0x2084, /* M-Audio Venom */
> +		   QUIRK_FLAG_MIXER_GET_SAMPLE_RATE | QUIRK_FLAG_DISABLE_AUTOSUSPEND),
>  	DEVICE_FLG(0x07fd, 0x000b, /* MOTU M Series 2nd hardware revision */
>  		   QUIRK_FLAG_CTL_MSG_DELAY_1M),
>  	DEVICE_FLG(0x08bb, 0x2702, /* LineX FM Transmitter */

This caused a build error.  A typo of QUIRK_FLAG_GET_SAMPLE_RATE?


thanks,

Takashi