X11 pen detection: fix misclassification due to improper init #2
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xinput2_device_is_pen() was testing against default-zero values in the X11 selector cache on at least the first round of detections, leading to imprecise detection. The patch fixes two aspects of initialisation: 1. Ensure that the selector cache is always initialised before any calls to xinput2_device_is_pen() by adding a call to pen_atoms_ensure_initialized() into X11_InitPen(). That new call also control-dominates all of the other calls to pen_atoms_ensure_initialized(), so they are no longer needed. 2. Ensure that all X11 Atoms used in SDL_x11pen.c are instantiated if missing. This ensures that they are never `None` and avoids potential failures to detect hot-plugged tablet devices.
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xinput2_device_is_pen() was testing against default-zero values in the X11 selector cache on at least the first round of detections, leading to imprecise detection.
Description
The patch fixes two aspects of initialisation:
Ensure that the selector cache is always initialised before any calls to xinput2_device_is_pen() by adding a call to pen_atoms_ensure_initialized() into X11_InitPen(). That new call also control-dominates all of the other calls to
pen_atoms_ensure_initialized(), so they are no longer needed.
Ensure that all X11 Atoms used in SDL_x11pen.c are instantiated if missing. This ensures that they are never
Noneand avoids potential failures to detect hot-plugged tablet devices.Existing Issue(s)
Might fix libsdl-org#8611