Re: [PATCH v6] usb: core: Add "quirks" parameter for usbcore

[Matthew Wilcox]

On Tue, Mar 13, 2018 at 03:26:19PM +0800, Kai-Heng Feng wrote:
> +	usbcore.quirks=
> +			[USB] A list of quirks entries to supplement or
> +			override the built-in usb core quirk list.  List
> +			entries are separated by commas.  Each entry has
> +			the form VID:PID:Flags where VID and PID are Vendor
> +			and Product ID values (4-digit hex numbers) and
> +			Flags is a set of characters, each corresponding
> +			to a common usb core quirk flag as follows:

This doesn't really tell me that the specified quirks will be XORed with
the built-in quirks.  Maybe something like ...

			[USB] A list of quirk entries to augment the
			built-in usb core quirk list.  List entries are
			separated by commas.  Each entry has the form
			VendorID:ProductID:Flags.  The IDs are 4-digit hex
			numbers and Flags is a set of letters.  Each letter
			will change the built-in quirk; setting it if it is
			clear and clearing it if it is set.  The letters
			have the following meanings:

> +		/* Each entry consists of VID:PID:flags */
> +		field = strsep(&p, ":");
> +		if (!field)
> +			break;
> +
> +		if (kstrtou16(field, 16, &vid))
> +			break;
> +
> +		field = strsep(&p, ":");
> +		if (!field)
> +			break;
> +
> +		if (kstrtou16(field, 16, &pid))
> +			break;

Is there a reason to not use sscanf here like hid-quirks.c does?