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From: Peter Maydell <peter.maydell@linaro.org>
Date: Wed, 23 Sep 2015 17:34:57 -0700
Message-ID: <CAFEAcA_uMarFaJC7BBpN6YNgRnjPErKiXRjPVoiDqJg4WEFRmw@mail.gmail.com>
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Subject: Re: [Qemu-devel] [PATCH v2] ui/cocoa.m: prevent stuck key situation
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To: Programmingkid <programmingkidx@gmail.com>
Cc: qemu-devel qemu-devel <qemu-devel@nongnu.org>

On 23 September 2015 at 17:17, Programmingkid <programmingkidx@gmail.com> wrote:
> When the user puts QEMU in the background while holding
> down a key, QEMU will not receive the keyup event when
> the user lets go of the key. When the user goes back to
> QEMU, QEMU will think the key is still down causing
> stuck key symptoms. This patch fixes this problem by
> releasing all down keys when QEMU goes into the
> background.
>
> Signed-off-by: John Arbuckle <programmingkidx@gmail.com>
>
> ---
> Removed the modifiers_state global variable.
> Added a raiseAllKeys method.
>
>  ui/cocoa.m |   26 ++++++++++++++++++++++++++
>  1 files changed, 26 insertions(+), 0 deletions(-)
>
> diff --git a/ui/cocoa.m b/ui/cocoa.m
> index 334e6f6..4d15553 100644
> --- a/ui/cocoa.m
> +++ b/ui/cocoa.m
> @@ -304,6 +304,7 @@ static void handleAnyDeviceErrors(Error * err)
>  - (float) cdx;
>  - (float) cdy;
>  - (QEMUScreen) gscreen;
> +- (void) raiseAllKeys;
>  @end
>
>  QemuCocoaView *cocoaView;
> @@ -798,6 +799,23 @@ QemuCocoaView *cocoaView;
>  - (float) cdx {return cdx;}
>  - (float) cdy {return cdy;}
>  - (QEMUScreen) gscreen {return screen;}
> +
> +/*
> + * Makes the target think all down keys are being released.
> + * This prevents a stuck key problem.

", since we will not see key up events for those keys after we
have lost focus."

> + */
> +- (void) raiseAllKeys
> +{
> +    int index;
> +    const int max_index = 220; /* This is the highest value key */

No, you need to use ARRAY_SIZE.

> +
> +   for (index = 0; index <= max_index; index++) {
> +       if (modifiers_state[index]) {
> +           modifiers_state[index] = 0;
> +           qemu_input_event_send_key_number(dcl->con, index, false);
> +       }
> +   }

-- PMM