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From: Benjamin Tissoires <benjamin.tissoires@redhat.com>
To: Henrik Rydberg <rydberg@bitmath.org>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>,
	Hans de Goede <hdegoede@redhat.com>,
	Peter Hutterer <peter.hutterer@redhat.com>,
	linux-input@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/3] Input: mt - prevent balanced slot assignment to assign twice the slot
Date: Tue, 31 Mar 2015 10:58:19 -0400	[thread overview]
Message-ID: <20150331145818.GA30670@mail.corp.redhat.com> (raw)
In-Reply-To: <20150331072430.GA25785@polaris.bitmath.org>

Hi Henrik,

On Mar 31 2015 or thereabouts, Henrik Rydberg wrote:
> Hi Benjamin,
> 
> > If two touches are under the dmax distance, it looks like they can now
> > be assigned to the same slot. Add a band aid to prevent such situation
> > and be able to use the balanced slot assignment.
> 
> Yes, great find. You patch is correct, but it is not a band aid, but a
> result stemming from a limitation in how equality constraints (read
> unique assignments) can be handled in the iterative algorithm. This
> cannot happen in the original algorithm, because of the extra
> penalization for overcovers.
> 
> Here is an alternative version which cleans up the loop logic
> somewhat, together with a different commit message. I did not have any
> opportunity to check this in hardware. I you like it and find it
> working, then please take over the authorship and just add a
> signed-off from me.

OK, it works just fine. So I'll resend the series with Hans' ACK and
your v2. Thanks for your quick respin.

Cheers,
Benjamin

> 
> Thanks,
> Henrik
> 
> ---
> 
> From e00d63f6cadf20d871bed763b3531428b34d785c Mon Sep 17 00:00:00 2001
> From: Henrik Rydberg <rydberg@bitmath.org>
> Date: Tue, 31 Mar 2015 09:10:02 +0200
> Subject: [PATCH] Input: MT - make slot assignment work for overcovered
>  solutions
> 
> The recent inclusion of a deassignment cost in the slot assignment
> algorithm did not properly account for the corner cases where the
> solutions are overcovered. This patch makes sure the resulting assignment
> is unique, allocating new slots when necessary.
> 
> UNTESTED
> ---
>  drivers/input/input-mt.c | 21 ++++++++++++---------
>  1 file changed, 12 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/input/input-mt.c b/drivers/input/input-mt.c
> index fbe29fc..17e80a6 100644
> --- a/drivers/input/input-mt.c
> +++ b/drivers/input/input-mt.c
> @@ -363,25 +363,28 @@ static void input_mt_set_slots(struct input_mt *mt,
>  			       int *slots, int num_pos)
>  {
>  	struct input_mt_slot *s;
> -	int *w = mt->red, *p;
> +	int *w = mt->red, j;
>  
> -	for (p = slots; p != slots + num_pos; p++)
> -		*p = -1;
> +	for (j = 0; j != num_pos; j++)
> +		slots[j] = -1;
>  
>  	for (s = mt->slots; s != mt->slots + mt->num_slots; s++) {
>  		if (!input_mt_is_active(s))
>  			continue;
> -		for (p = slots; p != slots + num_pos; p++)
> -			if (*w++ < 0)
> -				*p = s - mt->slots;
> +		for (j = 0; j != num_pos; j++)
> +			if (w[j] < 0) {
> +				slots[j] = s - mt->slots;
> +				break;
> +			}
> +		w += num_pos;
>  	}
>  
>  	for (s = mt->slots; s != mt->slots + mt->num_slots; s++) {
>  		if (input_mt_is_active(s))
>  			continue;
> -		for (p = slots; p != slots + num_pos; p++)
> -			if (*p < 0) {
> -				*p = s - mt->slots;
> +		for (j = 0; j != num_pos; j++)
> +			if (slots[j] < 0) {
> +				slots[j] = s - mt->slots;
>  				break;
>  			}
>  	}
> -- 
> 2.3.0
> 

  reply	other threads:[~2015-03-31 14:58 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-03-30 22:09 [PATCH 0/3] Balanced slots, attempt #2 Benjamin Tissoires
2015-03-30 22:09 ` [PATCH 1/3] Input: mt - prevent balanced slot assignment to assign twice the slot Benjamin Tissoires
2015-03-31  7:24   ` Henrik Rydberg
2015-03-31 14:58     ` Benjamin Tissoires [this message]
2015-03-30 22:09 ` [PATCH 2/3] Revert "Revert "Input: synaptics - use dmax in input_mt_assign_slots"" Benjamin Tissoires
2015-03-30 22:09 ` [PATCH 3/3] Input: synaptics - allocate 3 slots to keep stability in image sensors Benjamin Tissoires
2015-03-31  7:11 ` [PATCH 0/3] Balanced slots, attempt #2 Hans de Goede

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