Re: [RFC][PATCH] input: Introduce device information ioctl

[Greg KH <greg@kroah.com>]

On Tue, Dec 07, 2010 at 08:25:26AM +0100, Henrik Rydberg wrote:
>  /**
> + * struct input_devinfo - device information via EVIOCGDEVINFO ioctl
> + * @types: bitmask of types (DEVTYPE_*) matching this device
> + * @capabilities: bitmask of capabilities (DEVCAPS_*) of this device
> + *
> + * This struct provides information about the device needed for
> + * automatic setup in userspace, such as if the device is direct
> + * (touchscreen) or indirect (touchpad), and if there are other
> + * special considerations, such as the touchpad also being a button.
> + */
> +struct input_devinfo {
> +	__u32 types;
> +	__u32 capabilities;
> +};

Why use an ioctl for this at all?  It's just 2 simple values that don't
need to be atomically read at the same time.  What's wrong with 2 more
sysfs files?

thanks,

greg k-h