[PATCH evdev 3/3] Add handling for tablets that do not send axes with tools (#29645)

[Chris Bagwell]

Reviewed-by: Chris Bagwell <chris at cnpbagwell.com>

Hmmm, guess xf86-input-wacom would need similar logic to handle same
non-wacom tablets.

But then again with this series of changes xf86-input-evdev may be
better choice for 1 tool tablets.

Chris

On Sun, Oct 10, 2010 at 6:33 PM, Peter Hutterer
<peter.hutterer at who-t.net> wrote:
> Some tablets send axis values, then EV_SYN, and in the next event the
> BTN_TOOL_PEN/BTN_TOUCH, etc. For these tablets, the cursor doesn't move as
> coordinates while not in proximity are ignored.
>
> Buffer coordinates received while out-of-proximity and if we get a proximity
> event without other coordinates, re-use the last ones received.
>
> X.Org Bug 29645 <http://bugs.freedesktop.org/show_bug.cgi?id=29645>
>
> Signed-off-by: Peter Hutterer <peter.hutterer at who-t.net>
> ---
>  src/evdev.c |   56 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  src/evdev.h |    1 +
>  2 files changed, 57 insertions(+), 0 deletions(-)
>
> diff --git a/src/evdev.c b/src/evdev.c
> index 634c174..0ef7170 100644
> --- a/src/evdev.c
> +++ b/src/evdev.c
> @@ -481,6 +481,60 @@ EvdevProcessProximityEvent(InputInfoPtr pInfo, struct input_event *ev)
>  }
>
>  /**
> + * Proximity handling is rather weird because of tablet-specific issues.
> + * Some tablets, notably Wacoms, send a 0/0 coordinate in the same EV_SYN as
> + * the out-of-proximity notify. We need to ignore those, hence we only
> + * actually post valuator events when we're in proximity.
> + *
> + * Other tablets send the x/y coordinates, then EV_SYN, then the proximity
> + * event. For those, we need to remember x/y to post it when the proximity
> + * comes.
> + *
> + * If we're not in proximity and we get valuator events, remember that, they
> + * won't be posted though. If we move into proximity without valuators, use
> + * the last ones we got and let the rest of the code post them.
> + */
> +static int
> +EvdevProcessProximityState(InputInfoPtr pInfo)
> +{
> +    EvdevPtr pEvdev = pInfo->private;
> +    int prox_state = 0;
> +    int i;
> +
> +    /* no proximity change in the queue */
> +    if (!pEvdev->prox)
> +    {
> +        if (pEvdev->abs && !pEvdev->proximity)
> +            pEvdev->abs_prox = pEvdev->abs;
> +        return 0;
> +    }
> +
> +    for (i = 0; pEvdev->prox && i < pEvdev->num_queue; i++)
> +    {
> +        if (pEvdev->queue[i].type == EV_QUEUE_PROXIMITY)
> +        {
> +            prox_state = pEvdev->queue[i].val;
> +            break;
> +        }
> +    }
> +
> +    if ((prox_state && !pEvdev->proximity) ||
> +        (!prox_state && pEvdev->proximity))
> +    {
> +        /* We're about to go into/out of proximity but have no abs events
> +         * within the EV_SYN. Use the last coordinates we have. */
> +        if (!pEvdev->abs && pEvdev->abs_prox)
> +        {
> +            pEvdev->abs = pEvdev->abs_prox;
> +            pEvdev->abs_prox = 0;
> +        }
> +    }
> +
> +    pEvdev->proximity = prox_state;
> +    return 1;
> +}
> +
> +/**
>  * Take a button input event and process it accordingly.
>  */
>  static void
> @@ -732,6 +786,8 @@ EvdevProcessSyncEvent(InputInfoPtr pInfo, struct input_event *ev)
>     int v[MAX_VALUATORS] = {};
>     EvdevPtr pEvdev = pInfo->private;
>
> +    EvdevProcessProximityState(pInfo);
> +
>     EvdevProcessValuators(pInfo, v, &num_v, &first_v);
>
>     EvdevPostProximityEvents(pInfo, TRUE, num_v, first_v, v);
> diff --git a/src/evdev.h b/src/evdev.h
> index 08f3c13..af93d41 100644
> --- a/src/evdev.h
> +++ b/src/evdev.h
> @@ -133,6 +133,7 @@ typedef struct {
>
>     int delta[REL_CNT];
>     unsigned int abs, rel, prox;
> +    unsigned int abs_prox;  /* valuators posted while out of prox? */
>
>     /* XKB stuff has to be per-device rather than per-driver */
>  #if GET_ABI_MAJOR(ABI_XINPUT_VERSION) < 5
> --
> 1.7.2.3
>
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