Re: Regression in Final Scratch 'ScratchAmp' quirk (DJ interface)

[Geraldo Nascimento <geraldogabriel@gmail.com>]

On Wed, Jan 03, 2024 at 03:54:29PM +0000, Mark Hills wrote:
> The ScratchAmp worked perfectly with a quirk, but now that seems to have 
> regressed and the device is no longer detected [1].
> 
> It's design is from 2002, based on class-compliant (Philips UDA1325H) 
> chips. It hides itself behind a 'vendor specific' description, presumably 
> as it was launched in a closed system with specific hardware and software 
> for DJ'ing.

Hi Mark, great fan of your work with xwax here.

Perhaps adding USB_DEVICE_VENDOR_SPEC(0x103d, 0x0100) and
USB_DEVICE_VENDOR_SPEC(0x103d, 0x0101) to quirks-table.h can do the
trick?

Regards,
Geraldo Nascimento

> 
> So this quirk was introduced in 2007:
> 
> +/* Stanton/N2IT Final Scratch v1 device ('Scratchamp') */
> +{
> +	USB_DEVICE(0x103d, 0x0100),
> +		.driver_info = (unsigned long) & (const struct snd_usb_audio_quirk) {
> +		.vendor_name = "Stanton",
> +		.product_name = "ScratchAmp",
> +		.ifnum = QUIRK_NO_INTERFACE
> +	}
> +},
> +{
> +	USB_DEVICE(0x103d, 0x0101),
> +		.driver_info = (unsigned long) & (const struct snd_usb_audio_quirk) {
> +		.vendor_name = "Stanton",
> +		.product_name = "ScratchAmp",
> +		.ifnum = QUIRK_NO_INTERFACE
> +	}
> +},
> 
> In a modern kernel, the (ineffective) quirk is now in sound/usb/card.c:
> 
> +	/* Stanton/N2IT Final Scratch v1 device ('Scratchamp') */
> +	DEVICE_NAME(0x103d, 0x0100, "Stanton", "ScratchAmp"),
> +	DEVICE_NAME(0x103d, 0x0101, "Stanton", "ScratchAmp"),
> 
> Is there a functional difference between these quirks and/or any reason 
> the device would no longer be detected?
> 
> I noted the commits went via use of QUIRK_RENAME_DEVICE(), perhaps 
> misleading the refactoring to assume the quirk was purely a rename.
> 
> Below is an "lsusb" of the device, dated from 2008; I don't currently have 
> access to my own device, or know exactly when this regressed.
> 
> Many thanks
> 
> [1] https://sourceforge.net/p/xwax/mailman/message/48496984/
> [2] http://www.pogo.org.uk/~mark/linuxdj/scratchamp.html
> [3] https://finalscratch.sourceforge.net/innards/
> 
> -- 
> Mark