Jason Wyatt
Currently the keymapnotify event handling is commented out as FIXME in SDL_x11events.c (It looks like this may have functioned SDL1.2).
Not handling this event means that if a window manager shortcut such as ALT+SPACE is used, SDL will send an ALT key down signal, but not an up signal. Also querying SDL about the key state, it believes the ALT key remains pressed.
X passes the events keypress (alt), ?focusout?, ?focusin?, keymapnotify.
Zack Middleton
Using X11 (on Debian Wheezy), SDL_GetModState() & KMOD_NUM and KMOD_CAPS are not set to system state (numlock/capslock LEDs). Pressing numlock or capslock toggles the mod state, though if num/caps lock is enabled before starting the program it's still reversed from system state. This makes getting KMOD_NUM and KMOD_CAPS in programs unreliable. This can be seen using the checkkeys test program.
The function that appears to have handle this in SDL 1.2 is X11_SetKeyboardState. The function call is commented out with "FIXME:" in SDL 2.
Using Windows backend through WINE; on first key press if numlock and/or capslock is enabled on system, numlock/capslock SDL_SendKeyboardKey is run and toggles KMOD_NUM/KMOD_CAPS to the correct state. On X11 this does not happen.
The attached patch makes X11 backend set keyboard state on window focus if no window was previously focused. It sets all keys to system up/down state and toggles KMOD_NUM/KMOD_CAPS via SDL_SendKeyboardKey to match system if needed. The patch is based on SDL 1.2's X11_SetKeyboardState.
An existing hint lets apps that don't need the timer resolution changed avoid
this, to save battery, etc, but this fixes several problems in timing, audio
callbacks not firing fast enough, etc.
Fixes Bugzilla #2944.
