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

[Bernhard Beschow]

Am 24. April 2023 03:33:05 UTC schrieb Stefan Weil <sw@weilnetz.de>:
>Am 18.04.23 um 08:56 schrieb Volker Rümelin:
>
>> 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>
>> ---
>>   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 */
>
>
>s/procecure/procedure/
>
>
>>       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
>
>
>The typo fix for the comment does not require a v3 and can be applied in the 
>pull request.
>
>Reviewed-by: Stefan Weil <sw@weilnetz.de>

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