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 <rydb...@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
>
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