Re: [RFC 2/2] input: evdev: Add EVIOC mechanism to extract the MT slot state

["Henrik Rydberg" <rydberg@euromail.se>]

On Thu, Jan 27, 2011 at 11:35:47AM +0100, Benjamin Tissoires wrote:
> This patch adds the ability to extract the MT slot state sequentially
> via EVIOCGABS. The slot parameter is first selected by calling
> EVIOCSABS with ABS_MT_SLOT as argument, followed by a set of EVIOCGABS
> calls. The slot selection is local to the evdev client handler, and
> does not affect the actual input state.

Ok - it seemed like a reasonable idea at the time, but..

> @@ -767,9 +769,10 @@ static long evdev_do_ioctl(struct file *file, unsigned int cmd,
>  			if (size < sizeof(struct input_absinfo))
>  				abs.resolution = 0;
>  
> -			/* We can't change number of reserved MT slots */
> -			if (t == ABS_MT_SLOT)
> -				return -EINVAL;
> +			if (t == ABS_MT_SLOT) {
> +				client->slot = abs.value;
> +				return 0;
> +			}

...this just does not look right. Perhaps there should really be a
different ioctl to retrieve the slot values instead. Dmitry?

Thanks,
Henrik