Hi Yufeng,
> We are already releasing all pressed keys on device reset and
> disconnect. This patch adds the finger release for multi-touch
> device.
>
> Different than the key release logic that only the pressed keys
> are released, here all the possible fingers are released even
> it is not recorded as touched down in the input_dev's internal
> state. The motivation is that while releasing an alreay released
> finger won't do harm to downstream, it is helpful in the case
> when the downstream is out of sync with input_dev's internal
> state, we are bringing them back to in sync by cleaning up both
> input_dev and downstream's finger states.
>
> Signed-off-by: Yufeng Shen <miletus@xxxxxxxxxxxx>
> ---
To reset the input state centrally upon disconnect makes some sense;
upon suspend/resume, less so. It is really up to the driver to
determine what part of the input state survives a suspend/resume
cycle
> drivers/input/input.c | 34 ++++++++++++++++++++++++++++++++--
> 1 files changed, 32 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/input/input.c b/drivers/input/input.c
> index 768e46b..ebdc450 100644
> --- a/drivers/input/input.c
> +++ b/drivers/input/input.c
> @@ -584,6 +584,34 @@ void input_close_device(struct input_handle *handle)
> EXPORT_SYMBOL(input_close_device);
>
> /*
> + * Simulate finger release events for all possible fingers. It has no harm
> + * to release an alreay released finger, but has the benefit that if the
> + * downstream finger states are out of sync with input_dev's finger states,
> + * we are helping to clean them up.
> + * The function must be called with dev->event_lock held.
> + */
> +static void input_dev_release_mt(struct input_dev *dev)
This should be moved to input-mt.c instead.
> +{
> + int i;
> +
> + if (!dev->mt)
> + return;
> +
> + if (!is_event_supported(EV_ABS, dev->evbit, EV_MAX) ||
> + !is_event_supported(ABS_MT_SLOT, dev->absbit, ABS_MAX) ||
> + !is_event_supported(ABS_MT_TRACKING_ID, dev->absbit, ABS_MAX))
> + return;
No need to check those; implied by mtsize != 0.
> +
> + for (i = 0; i < dev->mtsize; i++) {
> + input_mt_set_value(&dev->mt[i], ABS_MT_TRACKING_ID, -1);
> + input_pass_event(dev, EV_ABS, ABS_MT_SLOT, i);
> + input_pass_event(dev, EV_ABS, ABS_MT_TRACKING_ID, -1);
> + }
Please use the proper api here (see any mt driver for hints).
> +
> + input_pass_event(dev, EV_SYN, SYN_REPORT, 1);
input_sync()
> +}
> +
> +/*
> * Simulate keyup events for all keys that are marked as pressed.
> * The function must be called with dev->event_lock held.
> */
> @@ -627,6 +655,7 @@ static void input_disconnect_device(struct input_dev *dev)
> * reach any handlers.
> */
> input_dev_release_keys(dev);
> + input_dev_release_mt(dev);
>
> list_for_each_entry(handle, &dev->h_list, d_node)
> handle->open = 0;
> @@ -1569,7 +1598,7 @@ static void input_dev_toggle(struct input_dev *dev, bool activate)
> * @dev: input device whose state needs to be reset
> *
> * This function tries to reset the state of an opened input device and
> - * bring internal state and state if the hardware in sync with each other.
> + * bring internal state and state of the hardware in sync with each other.
> * We mark all keys as released, restore LED state, repeat rate, etc.
> */
> void input_reset_device(struct input_dev *dev)
> @@ -1581,10 +1610,11 @@ void input_reset_device(struct input_dev *dev)
>
> /*
> * Keys that have been pressed at suspend time are unlikely
> - * to be still pressed when we resume.
> + * to be still pressed when we resume. Same logic for MT.
> */
> spin_lock_irq(&dev->event_lock);
> input_dev_release_keys(dev);
> + input_dev_release_mt(dev);
Since this is called from input_dev_resume(), I am not so sure this is
a good idea. Rather, we should be able to rely on the driver's
suspend/resume implementation here.
> spin_unlock_irq(&dev->event_lock);
> }
>
> --
> 1.7.7.3
>
Thanks,
Henrik
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