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

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

[Ross Lagerwall via]

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.

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

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

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

[Daniel P. Berrangé]

We don't have any nominated maintainer for this ps2.c file. Unless
anyone objects, i'll pick this patch up into my next set of misc
fixes to be sent for this release.

On Mon, Feb 27, 2023 at 05:42:34PM +0000, Daniel P. Berrangé wrote:
> 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
> -- 
> |: https://berrange.com      -o-    https://www.flickr.com/photos/dberrange :|
> |: https://libvirt.org         -o-            https://fstop138.berrange.com :|
> |: https://entangle-photo.org    -o-    https://www.instagram.com/dberrange :|
> 
> 

With regards,
Daniel
-- 
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