Re: [PATCH v2 1/1] ui/sdl2: disable SDL_HINT_GRAB_KEYBOARD on Windows

[Bernhard Beschow]

Am 18. April 2023 06:56:52 UTC schrieb "Volker Rümelin" <vr_qemu@t-online.de>:
>Windows sends an extra left control key up/down input event for
>every right alt key up/down input event for keyboards with
>international layout. Since commit 830473455f ("ui/sdl2: fix
>handling of AltGr key on Windows") QEMU uses a Windows low level
>keyboard hook procedure to reliably filter out the special left
>control key and to grab the keyboard on Windows.
>
>The SDL2 version 2.0.16 introduced its own Windows low level
>keyboard hook procedure to grab the keyboard. Windows calls this
>callback before the QEMU keyboard hook procedure. This disables
>the special left control key filter when the keyboard is grabbed.
>
>To fix the problem, disable the SDL2 Windows low level keyboard
>hook procedure.
>
>Reported-by: Bernhard Beschow <shentey@gmail.com>
>Signed-off-by: Volker Rümelin <vr_qemu@t-online.de>

FWIW:

Tested-by: Bernhard Beschow <shentey@gmail.com>

>---
> ui/sdl2.c | 3 +++
> 1 file changed, 3 insertions(+)
>
>diff --git a/ui/sdl2.c b/ui/sdl2.c
>index 00aadfae37..9d703200bf 100644
>--- a/ui/sdl2.c
>+++ b/ui/sdl2.c
>@@ -855,7 +855,10 @@ static void sdl2_display_init(DisplayState *ds, 
>DisplayOptions *o)
> #ifdef SDL_HINT_VIDEO_X11_NET_WM_BYPASS_COMPOSITOR /* only available since 
> SDL 2.0.8 */
>     SDL_SetHint(SDL_HINT_VIDEO_X11_NET_WM_BYPASS_COMPOSITOR, "0");
> #endif
>+#ifndef CONFIG_WIN32
>+    /* QEMU uses its own low level keyboard hook procecure on Windows */
>     SDL_SetHint(SDL_HINT_GRAB_KEYBOARD, "1");
>+#endif
> #ifdef SDL_HINT_ALLOW_ALT_TAB_WHILE_GRABBED
>     SDL_SetHint(SDL_HINT_ALLOW_ALT_TAB_WHILE_GRABBED, "0");
> #endif