Re: [PATCH] ps2: Don't send key release event for Lang1, Lang2 keys

[Daniel P . Berrangé]

On Mon, Feb 27, 2023 at 05:33:08PM +0000, Ross Lagerwall wrote:
> The scancodes for the Lang1 and Lang2 keys (i.e. Hangeul, Hanja) are
> special since they already have the 0x80 bit set which is commonly used
> to indicate a key release in AT set 1. Reportedly, real hardware does
> not send a key release scancode. So, skip sending a release for these
> keys. This ensures that Windows behaves correctly and interprets it as a
> single keypress rather than two consecutive keypresses.

A reference for this assertion would be:

  https://www.win.tue.nl/~aeb/linux/kbd/scancodes-9.html

   "The Korean keyboard has two keys, the Korean/Chinese and
    the Korean/English toggles, that generate scancodes f1
    and f2 (respectively) when pressed, and nothing when
    released."

> 
> Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com>
> ---
>  hw/input/ps2.c | 6 ++++++
>  1 file changed, 6 insertions(+)

Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>

> 
> diff --git a/hw/input/ps2.c b/hw/input/ps2.c
> index 3253ab6a92..45af76a837 100644
> --- a/hw/input/ps2.c
> +++ b/hw/input/ps2.c
> @@ -402,6 +402,9 @@ static void ps2_keyboard_event(DeviceState *dev, 
> QemuConsole *src,
>                      ps2_put_keycode(s, 0xaa);
>                  }
>              }
> +        } else if ((qcode == Q_KEY_CODE_LANG1 || qcode == Q_KEY_CODE_LANG2)
> +                   && !key->down) {
> +            /* Ignore release for these keys */
>          } else {
>              if (qcode < qemu_input_map_qcode_to_atset1_len) {
>                  keycode = qemu_input_map_qcode_to_atset1[qcode];
> @@ -497,6 +500,9 @@ static void ps2_keyboard_event(DeviceState *dev, 
> QemuConsole *src,
>                      ps2_put_keycode(s, 0x12);
>                  }
>              }
> +        } else if ((qcode == Q_KEY_CODE_LANG1 || qcode == Q_KEY_CODE_LANG2) 
> &&
> +                   !key->down) {
> +            /* Ignore release for these keys */
>          } else {
>              if (qcode < qemu_input_map_qcode_to_atset2_len) {
>                  keycode = qemu_input_map_qcode_to_atset2[qcode];
> -- 
> 2.31.1
> 

With regards,
Daniel
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