Re: [PATCH 3/3] ALSA: usb-audio: Properly match with audio interface class

[Alexander Tsoy <alexander@tsoy.me>]

В Пн, 17/08/2020 в 10:21 +0200, Takashi Iwai пишет:
> There are a few entries in the quirk table that set the device ID
> with
> USB_DEVICE() macro while having an extra bInterfaceClass field.  But
> bInterfaceClass field is never checked unless the proper match_flags
> is set, so those may match incorrectly with all interfaces.
> 
> Introduce another macro to match with the vid/pid pair and the audio
> class interface, and apply it to such entries, so that they can match
> properly.
> 
> Signed-off-by: Takashi Iwai <tiwai@suse.de>
> ---
>  sound/usb/quirks-table.h | 55 +++++++++++++++++---------------------
> ----------
>  1 file changed, 19 insertions(+), 36 deletions(-)
> 
> diff --git a/sound/usb/quirks-table.h b/sound/usb/quirks-table.h
> index 988bb9d00192..7a80ef31bbe4 100644
> --- a/sound/usb/quirks-table.h
> +++ b/sound/usb/quirks-table.h
> @@ -35,6 +35,14 @@
>  	.bInterfaceClass = USB_CLASS_AUDIO, \
>  	.bInterfaceSubClass = USB_SUBCLASS_AUDIOCONTROL
>  
> +/* Another standard entry matching with vid/pid and the audio class
> */
> +#define USB_AUDIO_CLASS(vend, prod) \
> +	.match_flags = USB_DEVICE_ID_MATCH_DEVICE | \
> +		       USB_DEVICE_ID_MATCH_INT_CLASS, \
> +	.idVendor = vend, \
> +	.idProduct = prod, \
> +	.bInterfaceClass = USB_CLASS_AUDIO
> +
>  /* FTDI devices */
>  {
>  	USB_DEVICE(0x0403, 0xb8d8),
> @@ -68,34 +76,14 @@
>  	}
>  },
>  
> -{
> -	/* E-Mu 0202 USB */
> -	.match_flags = USB_DEVICE_ID_MATCH_DEVICE,
> -	.idVendor = 0x041e,
> -	.idProduct = 0x3f02,
> -	.bInterfaceClass = USB_CLASS_AUDIO,
> -},
> -{
> -	/* E-Mu 0404 USB */
> -	.match_flags = USB_DEVICE_ID_MATCH_DEVICE,
> -	.idVendor = 0x041e,
> -	.idProduct = 0x3f04,
> -	.bInterfaceClass = USB_CLASS_AUDIO,
> -},
> -{
> -	/* E-Mu Tracker Pre */
> -	.match_flags = USB_DEVICE_ID_MATCH_DEVICE,
> -	.idVendor = 0x041e,
> -	.idProduct = 0x3f0a,
> -	.bInterfaceClass = USB_CLASS_AUDIO,
> -},
> -{
> -	/* E-Mu 0204 USB */
> -	.match_flags = USB_DEVICE_ID_MATCH_DEVICE,
> -	.idVendor = 0x041e,
> -	.idProduct = 0x3f19,
> -	.bInterfaceClass = USB_CLASS_AUDIO,
> -},
> +/* E-Mu 0202 USB */
> +{ USB_AUDIO_CLASS(0x041e, 0x3f02) },
> +/* E-Mu 0404 USB */
> +{ USB_AUDIO_CLASS(0x041e, 0x3f04) },
> +/* E-Mu Tracker Pre */
> +{ USB_AUDIO_CLASS(0x041e, 0x3f0a) },
> +/* E-Mu 0204 USB */
> +{ USB_AUDIO_CLASS(0x041e, 0x3f19) },
>  
>  /*
>   * HP Wireless Audio
> @@ -2751,10 +2739,7 @@ YAMAHA_DEVICE(0x7010, "UB99"),
>  },
>  
>  /* KeithMcMillen Stringport */
> -{
> -	USB_DEVICE(0x1f38, 0x0001),
> -	.bInterfaceClass = USB_CLASS_AUDIO,
> -},
> +{ USB_AUDIO_CLASS(0x1f38, 0x0001) },
>  
>  /* Miditech devices */
>  {
> @@ -2977,10 +2962,7 @@ AU0828_DEVICE(0x2040, 0x7270, "Hauppauge",
> "HVR-950Q"),
>  },
>  {
>  	/* Tascam US122 MKII - playback-only support */
> -	.match_flags = USB_DEVICE_ID_MATCH_DEVICE,
> -	.idVendor = 0x0644,
> -	.idProduct = 0x8021,
> -	.bInterfaceClass = USB_CLASS_AUDIO,
> +	USB_AUDIO_CLASS(0x0644, 0x8021),
>  	.driver_info = (unsigned long) &(const struct
> snd_usb_audio_quirk) {
>  		.vendor_name = "TASCAM",
>  		.product_name = "US122 MKII",
> @@ -3612,3 +3594,4 @@ AU0828_DEVICE(0x2040, 0x7270, "Hauppauge",
> "HVR-950Q"),
>  
>  #undef USB_DEVICE_VENDOR_SPEC
>  #undef USB_AUDIO_DEVICE
> +#undef USB_AUDIO_CLASS

I don't know anything about KeithMcMillen Stringport, but all other
devices (US122 MKII and E-mu) seems to have Vendor-specific Class. And
since the driver should already match all compliant devices, the only
potentional use for USB_AUDIO_CLASS macro is for devices
with bInterfaceClass = USB_CLASS_AUDIO and with some invalid
bInterfaceSubClass.